text: /*-------------------------------------------------------------------------
   *
   * parse_utilcmd.c
   *	  Perform parse analysis work for various utility commands
   *
   * Formerly we did this work during parse_analyze() in analyze.c.  However
   * that is fairly unsafe in the presence of querytree caching, since any
   * database state that we depend on in making the transformations might be
   * obsolete by the time the utility command is executed; and utility commands
   * have no infrastructure for holding locks or rechecking plan validity.
   * Hence these functions are now called at the start of execution of their
   * respective utility commands.
   *
   * NOTE: in general we must avoid scribbling on the passed-in raw parse
   * tree, since it might be in a plan cache.  The simplest solution is
   * a quick copyObject() call before manipulating the query tree.
   *
   *
   * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   *	$PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.40.4.1 2010/08/18 18:35:30 tgl Exp $
   *
   *-------------------------------------------------------------------------
   */
  
  #include "postgres.h"
  
  #include "access/genam.h"
  #include "access/heapam.h"
  #include "access/reloptions.h"
  #include "catalog/dependency.h"
  #include "catalog/heap.h"
  #include "catalog/index.h"
  #include "catalog/namespace.h"
  #include "catalog/pg_constraint.h"
  #include "catalog/pg_opclass.h"
  #include "catalog/pg_operator.h"
  #include "catalog/pg_type.h"
  #include "commands/comment.h"
  #include "commands/defrem.h"
  #include "commands/tablecmds.h"
  #include "commands/tablespace.h"
  #include "miscadmin.h"
  #include "nodes/makefuncs.h"
  #include "nodes/nodeFuncs.h"
  #include "parser/analyze.h"
  #include "parser/parse_clause.h"
  #include "parser/parse_expr.h"
  #include "parser/parse_relation.h"
  #include "parser/parse_target.h"
  #include "parser/parse_type.h"
  #include "parser/parse_utilcmd.h"
  #include "parser/parser.h"
  #include "rewrite/rewriteManip.h"
  #include "utils/acl.h"
  #include "utils/builtins.h"
  #include "utils/lsyscache.h"
  #include "utils/relcache.h"
  #include "utils/syscache.h"
  #include "utils/typcache.h"
  
  
  /* State shared by transformCreateStmt and its subroutines */
  typedef struct
  {
  	const char *stmtType;		/* "CREATE TABLE" or "ALTER TABLE" */
  	RangeVar   *relation;		/* relation to create */
  	Relation	rel;			/* opened/locked rel, if ALTER */
  	List	   *inhRelations;	/* relations to inherit from */
  	bool		isalter;		/* true if altering existing table */
  	bool		hasoids;		/* does relation have an OID column? */
  	List	   *columns;		/* ColumnDef items */
  	List	   *ckconstraints;	/* CHECK constraints */
  	List	   *fkconstraints;	/* FOREIGN KEY constraints */
  	List	   *ixconstraints;	/* index-creating constraints */
  	List	   *inh_indexes;	/* cloned indexes from INCLUDING INDEXES */
  	List	   *blist;			/* "before list" of things to do before
  								 * creating the table */
  	List	   *alist;			/* "after list" of things to do after creating
  								 * the table */
  	IndexStmt  *pkey;			/* PRIMARY KEY index, if any */
  } CreateStmtContext;
  
  /* State shared by transformCreateSchemaStmt and its subroutines */
  typedef struct
  {
  	const char *stmtType;		/* "CREATE SCHEMA" or "ALTER SCHEMA" */
  	char	   *schemaname;		/* name of schema */
  	char	   *authid;			/* owner of schema */
  	List	   *sequences;		/* CREATE SEQUENCE items */
  	List	   *tables;			/* CREATE TABLE items */
  	List	   *views;			/* CREATE VIEW items */
  	List	   *indexes;		/* CREATE INDEX items */
  	List	   *triggers;		/* CREATE TRIGGER items */
  	List	   *grants;			/* GRANT items */
  } CreateSchemaStmtContext;
  
  
  static void transformColumnDefinition(ParseState *pstate,
  						  CreateStmtContext *cxt,
  						  ColumnDef *column);
  static void transformTableConstraint(ParseState *pstate,
  						 CreateStmtContext *cxt,
  						 Constraint *constraint);
  static void transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
  					 InhRelation *inhrelation);
  static void transformOfType(ParseState *pstate, CreateStmtContext *cxt,
  				TypeName *ofTypename);
  static char *chooseIndexName(const RangeVar *relation, IndexStmt *index_stmt);
  static IndexStmt *generateClonedIndexStmt(CreateStmtContext *cxt,
  						Relation parent_index, AttrNumber *attmap);
  static List *get_opclass(Oid opclass, Oid actual_datatype);
  static void transformIndexConstraints(ParseState *pstate,
  						  CreateStmtContext *cxt);
  static IndexStmt *transformIndexConstraint(Constraint *constraint,
  						 CreateStmtContext *cxt);
  static void transformFKConstraints(ParseState *pstate,
  					   CreateStmtContext *cxt,
  					   bool skipValidation,
  					   bool isAddConstraint);
  static void transformConstraintAttrs(ParseState *pstate, List *constraintList);
  static void transformColumnType(ParseState *pstate, ColumnDef *column);
  static void setSchemaName(char *context_schema, char **stmt_schema_name);
  
  
  /*
   * transformCreateStmt -
   *	  parse analysis for CREATE TABLE
   *
   * Returns a List of utility commands to be done in sequence.  One of these
   * will be the transformed CreateStmt, but there may be additional actions
   * to be done before and after the actual DefineRelation() call.
   *
   * SQL92 allows constraints to be scattered all over, so thumb through
   * the columns and collect all constraints into one place.
   * If there are any implied indices (e.g. UNIQUE or PRIMARY KEY)
   * then expand those into multiple IndexStmt blocks.
   *	  - thomas 1997-12-02
   */
  List *
  transformCreateStmt(CreateStmt *stmt, const char *queryString)
  {
  	ParseState *pstate;
  	CreateStmtContext cxt;
  	List	   *result;
  	List	   *save_alist;
  	ListCell   *elements;
  
  	/*
  	 * We must not scribble on the passed-in CreateStmt, so copy it.  (This is
  	 * overkill, but easy.)
  	 */
  	stmt = (CreateStmt *) copyObject(stmt);
  
  	/*
  	 * If the target relation name isn't schema-qualified, make it so.  This
  	 * prevents some corner cases in which added-on rewritten commands might
  	 * think they should apply to other relations that have the same name and
  	 * are earlier in the search path.	"istemp" is equivalent to a
  	 * specification of pg_temp, so no need for anything extra in that case.
  	 */
  	if (stmt->relation->schemaname == NULL && !stmt->relation->istemp)
  	{
  		Oid			namespaceid = RangeVarGetCreationNamespace(stmt->relation);
  
  		stmt->relation->schemaname = get_namespace_name(namespaceid);
  	}
  
  	/* Set up pstate */
  	pstate = make_parsestate(NULL);
  	pstate->p_sourcetext = queryString;
  
  	cxt.stmtType = "CREATE TABLE";
  	cxt.relation = stmt->relation;
  	cxt.rel = NULL;
  	cxt.inhRelations = stmt->inhRelations;
  	cxt.isalter = false;
  	cxt.columns = NIL;
  	cxt.ckconstraints = NIL;
  	cxt.fkconstraints = NIL;
  	cxt.ixconstraints = NIL;
  	cxt.inh_indexes = NIL;
  	cxt.blist = NIL;
  	cxt.alist = NIL;
  	cxt.pkey = NULL;
  	cxt.hasoids = interpretOidsOption(stmt->options);
  
  	Assert(!stmt->ofTypename || !stmt->inhRelations);	/* grammar enforces */
  
  	if (stmt->ofTypename)
  		transformOfType(pstate, &cxt, stmt->ofTypename);
  
  	/*
  	 * Run through each primary element in the table creation clause. Separate
  	 * column defs from constraints, and do preliminary analysis.
  	 */
  	foreach(elements, stmt->tableElts)
  	{
  		Node	   *element = lfirst(elements);
  
  		switch (nodeTag(element))
  		{
  			case T_ColumnDef:
  				transformColumnDefinition(pstate, &cxt,
  										  (ColumnDef *) element);
  				break;
  
  			case T_Constraint:
  				transformTableConstraint(pstate, &cxt,
  										 (Constraint *) element);
  				break;
  
  			case T_InhRelation:
  				transformInhRelation(pstate, &cxt,
  									 (InhRelation *) element);
  				break;
  
  			default:
  				elog(ERROR, "unrecognized node type: %d",
  					 (int) nodeTag(element));
  				break;
  		}
  	}
  
  	/*
  	 * transformIndexConstraints wants cxt.alist to contain only index
  	 * statements, so transfer anything we already have into save_alist.
  	 */
  	save_alist = cxt.alist;
  	cxt.alist = NIL;
  
  	Assert(stmt->constraints == NIL);
  
  	/*
  	 * Postprocess constraints that give rise to index definitions.
  	 */
  	transformIndexConstraints(pstate, &cxt);
  
  	/*
  	 * Postprocess foreign-key constraints.
  	 */
  	transformFKConstraints(pstate, &cxt, true, false);
  
  	/*
  	 * Output results.
  	 */
  	stmt->tableElts = cxt.columns;
  	stmt->constraints = cxt.ckconstraints;
  
  	result = lappend(cxt.blist, stmt);
  	result = list_concat(result, cxt.alist);
  	result = list_concat(result, save_alist);
  
  	return result;
  }
  
  /*
   * transformColumnDefinition -
   *		transform a single ColumnDef within CREATE TABLE
   *		Also used in ALTER TABLE ADD COLUMN
   */
  static void
  transformColumnDefinition(ParseState *pstate, CreateStmtContext *cxt,
  						  ColumnDef *column)
  {
  	bool		is_serial;
  	bool		saw_nullable;
  	bool		saw_default;
  	Constraint *constraint;
  	ListCell   *clist;
  
  	cxt->columns = lappend(cxt->columns, column);
  
  	/* Check for SERIAL pseudo-types */
  	is_serial = false;
  	if (column->typeName
  		&& list_length(column->typeName->names) == 1
  		&& !column->typeName->pct_type)
  	{
  		char	   *typname = strVal(linitial(column->typeName->names));
  
  		if (strcmp(typname, "serial") == 0 ||
  			strcmp(typname, "serial4") == 0)
  		{
  			is_serial = true;
  			column->typeName->names = NIL;
  			column->typeName->typeOid = INT4OID;
  		}
  		else if (strcmp(typname, "bigserial") == 0 ||
  				 strcmp(typname, "serial8") == 0)
  		{
  			is_serial = true;
  			column->typeName->names = NIL;
  			column->typeName->typeOid = INT8OID;
  		}
  
  		/*
  		 * We have to reject "serial[]" explicitly, because once we've set
  		 * typeid, LookupTypeName won't notice arrayBounds.  We don't need any
  		 * special coding for serial(typmod) though.
  		 */
  		if (is_serial && column->typeName->arrayBounds != NIL)
  			ereport(ERROR,
  					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  					 errmsg("array of serial is not implemented"),
  					 parser_errposition(pstate, column->typeName->location)));
  	}
  
  	/* Do necessary work on the column type declaration */
  	if (column->typeName)
  		transformColumnType(pstate, column);
  
  	/* Special actions for SERIAL pseudo-types */
  	if (is_serial)
  	{
  		Oid			snamespaceid;
  		char	   *snamespace;
  		char	   *sname;
  		char	   *qstring;
  		A_Const    *snamenode;
  		TypeCast   *castnode;
  		FuncCall   *funccallnode;
  		CreateSeqStmt *seqstmt;
  		AlterSeqStmt *altseqstmt;
  		List	   *attnamelist;
  
  		/*
  		 * Determine namespace and name to use for the sequence.
  		 *
  		 * Although we use ChooseRelationName, it's not guaranteed that the
  		 * selected sequence name won't conflict; given sufficiently long
  		 * field names, two different serial columns in the same table could
  		 * be assigned the same sequence name, and we'd not notice since we
  		 * aren't creating the sequence quite yet.  In practice this seems
  		 * quite unlikely to be a problem, especially since few people would
  		 * need two serial columns in one table.
  		 */
  		if (cxt->rel)
  			snamespaceid = RelationGetNamespace(cxt->rel);
  		else
  			snamespaceid = RangeVarGetCreationNamespace(cxt->relation);
  		snamespace = get_namespace_name(snamespaceid);
  		sname = ChooseRelationName(cxt->relation->relname,
  								   column->colname,
  								   "seq",
  								   snamespaceid);
  
  		ereport(NOTICE,
  				(errmsg("%s will create implicit sequence \"%s\" for serial column \"%s.%s\"",
  						cxt->stmtType, sname,
  						cxt->relation->relname, column->colname)));
  
  		/*
  		 * Build a CREATE SEQUENCE command to create the sequence object, and
  		 * add it to the list of things to be done before this CREATE/ALTER
  		 * TABLE.
  		 */
  		seqstmt = makeNode(CreateSeqStmt);
  		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
  		seqstmt->options = NIL;
  
  		/*
  		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
  		 * by the table's owner.  The current user might be someone else
  		 * (perhaps a superuser, or someone who's only a member of the owning
  		 * role), but the SEQUENCE OWNED BY mechanisms will bleat unless
  		 * table and sequence have exactly the same owning role.
  		 */
  		if (cxt->rel)
  			seqstmt->ownerId = cxt->rel->rd_rel->relowner;
  		else
  			seqstmt->ownerId = InvalidOid;
  
  		cxt->blist = lappend(cxt->blist, seqstmt);
  
  		/*
  		 * Build an ALTER SEQUENCE ... OWNED BY command to mark the sequence
  		 * as owned by this column, and add it to the list of things to be
  		 * done after this CREATE/ALTER TABLE.
  		 */
  		altseqstmt = makeNode(AlterSeqStmt);
  		altseqstmt->sequence = makeRangeVar(snamespace, sname, -1);
  		attnamelist = list_make3(makeString(snamespace),
  								 makeString(cxt->relation->relname),
  								 makeString(column->colname));
  		altseqstmt->options = list_make1(makeDefElem("owned_by",
  													 (Node *) attnamelist));
  
  		cxt->alist = lappend(cxt->alist, altseqstmt);
  
  		/*
  		 * Create appropriate constraints for SERIAL.  We do this in full,
  		 * rather than shortcutting, so that we will detect any conflicting
  		 * constraints the user wrote (like a different DEFAULT).
  		 *
  		 * Create an expression tree representing the function call
  		 * nextval('sequencename').  We cannot reduce the raw tree to cooked
  		 * form until after the sequence is created, but there's no need to do
  		 * so.
  		 */
  		qstring = quote_qualified_identifier(snamespace, sname);
  		snamenode = makeNode(A_Const);
  		snamenode->val.type = T_String;
  		snamenode->val.val.str = qstring;
  		snamenode->location = -1;
  		castnode = makeNode(TypeCast);
  		castnode->typeName = SystemTypeName("regclass");
  		castnode->arg = (Node *) snamenode;
  		castnode->location = -1;
  		funccallnode = makeNode(FuncCall);
  		funccallnode->funcname = SystemFuncName("nextval");
  		funccallnode->args = list_make1(castnode);
  		funccallnode->agg_order = NIL;
  		funccallnode->agg_star = false;
  		funccallnode->agg_distinct = false;
  		funccallnode->func_variadic = false;
  		funccallnode->over = NULL;
  		funccallnode->location = -1;
  
  		constraint = makeNode(Constraint);
  		constraint->contype = CONSTR_DEFAULT;
  		constraint->location = -1;
  		constraint->raw_expr = (Node *) funccallnode;
  		constraint->cooked_expr = NULL;
  		column->constraints = lappend(column->constraints, constraint);
  
  		constraint = makeNode(Constraint);
  		constraint->contype = CONSTR_NOTNULL;
  		constraint->location = -1;
  		column->constraints = lappend(column->constraints, constraint);
  	}
  
  	/* Process column constraints, if any... */
  	transformConstraintAttrs(pstate, column->constraints);
  
  	saw_nullable = false;
  	saw_default = false;
  
  	foreach(clist, column->constraints)
  	{
  		constraint = lfirst(clist);
  		Assert(IsA(constraint, Constraint));
  
  		switch (constraint->contype)
  		{
  			case CONSTR_NULL:
  				if (saw_nullable && column->is_not_null)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
  									column->colname, cxt->relation->relname),
  							 parser_errposition(pstate,
  												constraint->location)));
  				column->is_not_null = FALSE;
  				saw_nullable = true;
  				break;
  
  			case CONSTR_NOTNULL:
  				if (saw_nullable && !column->is_not_null)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
  									column->colname, cxt->relation->relname),
  							 parser_errposition(pstate,
  												constraint->location)));
  				column->is_not_null = TRUE;
  				saw_nullable = true;
  				break;
  
  			case CONSTR_DEFAULT:
  				if (saw_default)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("multiple default values specified for column \"%s\" of table \"%s\"",
  									column->colname, cxt->relation->relname),
  							 parser_errposition(pstate,
  												constraint->location)));
  				column->raw_default = constraint->raw_expr;
  				Assert(constraint->cooked_expr == NULL);
  				saw_default = true;
  				break;
  
  			case CONSTR_CHECK:
  				cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
  				break;
  
  			case CONSTR_PRIMARY:
  			case CONSTR_UNIQUE:
  				if (constraint->keys == NIL)
  					constraint->keys = list_make1(makeString(column->colname));
  				cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
  				break;
  
  			case CONSTR_EXCLUSION:
  				/* grammar does not allow EXCLUDE as a column constraint */
  				elog(ERROR, "column exclusion constraints are not supported");
  				break;
  
  			case CONSTR_FOREIGN:
  
  				/*
  				 * Fill in the current attribute's name and throw it into the
  				 * list of FK constraints to be processed later.
  				 */
  				constraint->fk_attrs = list_make1(makeString(column->colname));
  				cxt->fkconstraints = lappend(cxt->fkconstraints, constraint);
  				break;
  
  			case CONSTR_ATTR_DEFERRABLE:
  			case CONSTR_ATTR_NOT_DEFERRABLE:
  			case CONSTR_ATTR_DEFERRED:
  			case CONSTR_ATTR_IMMEDIATE:
  				/* transformConstraintAttrs took care of these */
  				break;
  
  			default:
  				elog(ERROR, "unrecognized constraint type: %d",
  					 constraint->contype);
  				break;
  		}
  	}
  }
  
  /*
   * transformTableConstraint
   *		transform a Constraint node within CREATE TABLE or ALTER TABLE
   */
  static void
  transformTableConstraint(ParseState *pstate, CreateStmtContext *cxt,
  						 Constraint *constraint)
  {
  	switch (constraint->contype)
  	{
  		case CONSTR_PRIMARY:
  		case CONSTR_UNIQUE:
  		case CONSTR_EXCLUSION:
  			cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
  			break;
  
  		case CONSTR_CHECK:
  			cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
  			break;
  
  		case CONSTR_FOREIGN:
  			cxt->fkconstraints = lappend(cxt->fkconstraints, constraint);
  			break;
  
  		case CONSTR_NULL:
  		case CONSTR_NOTNULL:
  		case CONSTR_DEFAULT:
  		case CONSTR_ATTR_DEFERRABLE:
  		case CONSTR_ATTR_NOT_DEFERRABLE:
  		case CONSTR_ATTR_DEFERRED:
  		case CONSTR_ATTR_IMMEDIATE:
  			elog(ERROR, "invalid context for constraint type %d",
  				 constraint->contype);
  			break;
  
  		default:
  			elog(ERROR, "unrecognized constraint type: %d",
  				 constraint->contype);
  			break;
  	}
  }
  
  /*
   * transformInhRelation
   *
   * Change the LIKE <subtable> portion of a CREATE TABLE statement into
   * column definitions which recreate the user defined column portions of
   * <subtable>.
   */
  static void
  transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
  					 InhRelation *inhRelation)
  {
  	AttrNumber	parent_attno;
  	Relation	relation;
  	TupleDesc	tupleDesc;
  	TupleConstr *constr;
  	AclResult	aclresult;
  	char	   *comment;
  
  	relation = parserOpenTable(pstate, inhRelation->relation, AccessShareLock);
  
  	if (relation->rd_rel->relkind != RELKIND_RELATION)
  		ereport(ERROR,
  				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
  				 errmsg("inherited relation \"%s\" is not a table",
  						inhRelation->relation->relname)));
  
  	/*
  	 * Check for SELECT privilages
  	 */
  	aclresult = pg_class_aclcheck(RelationGetRelid(relation), GetUserId(),
  								  ACL_SELECT);
  	if (aclresult != ACLCHECK_OK)
  		aclcheck_error(aclresult, ACL_KIND_CLASS,
  					   RelationGetRelationName(relation));
  
  	tupleDesc = RelationGetDescr(relation);
  	constr = tupleDesc->constr;
  
  	/*
  	 * Insert the copied attributes into the cxt for the new table definition.
  	 */
  	for (parent_attno = 1; parent_attno <= tupleDesc->natts;
  		 parent_attno++)
  	{
  		Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
  		char	   *attributeName = NameStr(attribute->attname);
  		ColumnDef  *def;
  
  		/*
  		 * Ignore dropped columns in the parent.
  		 */
  		if (attribute->attisdropped)
  			continue;
  
  		/*
  		 * Create a new column, which is marked as NOT inherited.
  		 *
  		 * For constraints, ONLY the NOT NULL constraint is inherited by the
  		 * new column definition per SQL99.
  		 */
  		def = makeNode(ColumnDef);
  		def->colname = pstrdup(attributeName);
  		def->typeName = makeTypeNameFromOid(attribute->atttypid,
  											attribute->atttypmod);
  		def->inhcount = 0;
  		def->is_local = true;
  		def->is_not_null = attribute->attnotnull;
  		def->raw_default = NULL;
  		def->cooked_default = NULL;
  		def->constraints = NIL;
  
  		/*
  		 * Add to column list
  		 */
  		cxt->columns = lappend(cxt->columns, def);
  
  		/*
  		 * Copy default, if present and the default has been requested
  		 */
  		if (attribute->atthasdef &&
  			(inhRelation->options & CREATE_TABLE_LIKE_DEFAULTS))
  		{
  			Node	   *this_default = NULL;
  			AttrDefault *attrdef;
  			int			i;
  
  			/* Find default in constraint structure */
  			Assert(constr != NULL);
  			attrdef = constr->defval;
  			for (i = 0; i < constr->num_defval; i++)
  			{
  				if (attrdef[i].adnum == parent_attno)
  				{
  					this_default = stringToNode(attrdef[i].adbin);
  					break;
  				}
  			}
  			Assert(this_default != NULL);
  
  			/*
  			 * If default expr could contain any vars, we'd need to fix 'em,
  			 * but it can't; so default is ready to apply to child.
  			 */
  
  			def->cooked_default = this_default;
  		}
  
  		/* Likewise, copy storage if requested */
  		if (inhRelation->options & CREATE_TABLE_LIKE_STORAGE)
  			def->storage = attribute->attstorage;
  		else
  			def->storage = 0;
  
  		/* Likewise, copy comment if requested */
  		if ((inhRelation->options & CREATE_TABLE_LIKE_COMMENTS) &&
  			(comment = GetComment(attribute->attrelid,
  								  RelationRelationId,
  								  attribute->attnum)) != NULL)
  		{
  			CommentStmt *stmt = makeNode(CommentStmt);
  
  			stmt->objtype = OBJECT_COLUMN;
  			stmt->objname = list_make3(makeString(cxt->relation->schemaname),
  									   makeString(cxt->relation->relname),
  									   makeString(def->colname));
  			stmt->objargs = NIL;
  			stmt->comment = comment;
  
  			cxt->alist = lappend(cxt->alist, stmt);
  		}
  	}
  
  	/*
  	 * Copy CHECK constraints if requested, being careful to adjust attribute
  	 * numbers
  	 */
  	if ((inhRelation->options & CREATE_TABLE_LIKE_CONSTRAINTS) &&
  		tupleDesc->constr)
  	{
  		AttrNumber *attmap = varattnos_map_schema(tupleDesc, cxt->columns);
  		int			ccnum;
  
  		for (ccnum = 0; ccnum < tupleDesc->constr->num_check; ccnum++)
  		{
  			char	   *ccname = tupleDesc->constr->check[ccnum].ccname;
  			char	   *ccbin = tupleDesc->constr->check[ccnum].ccbin;
  			Node	   *ccbin_node = stringToNode(ccbin);
  			Constraint *n = makeNode(Constraint);
  
  			change_varattnos_of_a_node(ccbin_node, attmap);
  
  			n->contype = CONSTR_CHECK;
  			n->location = -1;
  			n->conname = pstrdup(ccname);
  			n->raw_expr = NULL;
  			n->cooked_expr = nodeToString(ccbin_node);
  			cxt->ckconstraints = lappend(cxt->ckconstraints, n);
  
  			/* Copy comment on constraint */
  			if ((inhRelation->options & CREATE_TABLE_LIKE_COMMENTS) &&
  				(comment = GetComment(GetConstraintByName(RelationGetRelid(relation),
  														  n->conname),
  									  ConstraintRelationId,
  									  0)) != NULL)
  			{
  				CommentStmt *stmt = makeNode(CommentStmt);
  
  				stmt->objtype = OBJECT_CONSTRAINT;
  				stmt->objname = list_make3(makeString(cxt->relation->schemaname),
  										   makeString(cxt->relation->relname),
  										   makeString(n->conname));
  				stmt->objargs = NIL;
  				stmt->comment = comment;
  
  				cxt->alist = lappend(cxt->alist, stmt);
  			}
  		}
  	}
  
  	/*
  	 * Likewise, copy indexes if requested
  	 */
  	if ((inhRelation->options & CREATE_TABLE_LIKE_INDEXES) &&
  		relation->rd_rel->relhasindex)
  	{
  		AttrNumber *attmap = varattnos_map_schema(tupleDesc, cxt->columns);
  		List	   *parent_indexes;
  		ListCell   *l;
  
  		parent_indexes = RelationGetIndexList(relation);
  
  		foreach(l, parent_indexes)
  		{
  			Oid			parent_index_oid = lfirst_oid(l);
  			Relation	parent_index;
  			IndexStmt  *index_stmt;
  
  			parent_index = index_open(parent_index_oid, AccessShareLock);
  
  			/* Build CREATE INDEX statement to recreate the parent_index */
  			index_stmt = generateClonedIndexStmt(cxt, parent_index, attmap);
  
  			/* Copy comment on index */
  			if (inhRelation->options & CREATE_TABLE_LIKE_COMMENTS)
  			{
  				comment = GetComment(parent_index_oid, RelationRelationId, 0);
  
  				if (comment != NULL)
  				{
  					CommentStmt *stmt;
  
  					/*
  					 * We have to assign the index a name now, so that we can
  					 * reference it in CommentStmt.
  					 */
  					if (index_stmt->idxname == NULL)
  						index_stmt->idxname = chooseIndexName(cxt->relation,
  															  index_stmt);
  
  					stmt = makeNode(CommentStmt);
  					stmt->objtype = OBJECT_INDEX;
  					stmt->objname =
  						list_make2(makeString(cxt->relation->schemaname),
  								   makeString(index_stmt->idxname));
  					stmt->objargs = NIL;
  					stmt->comment = comment;
  
  					cxt->alist = lappend(cxt->alist, stmt);
  				}
  			}
  
  			/* Save it in the inh_indexes list for the time being */
  			cxt->inh_indexes = lappend(cxt->inh_indexes, index_stmt);
  
  			index_close(parent_index, AccessShareLock);
  		}
  	}
  
  	/*
  	 * Close the parent rel, but keep our AccessShareLock on it until xact
  	 * commit.	That will prevent someone else from deleting or ALTERing the
  	 * parent before the child is committed.
  	 */
  	heap_close(relation, NoLock);
  }
  
  static void
  transformOfType(ParseState *pstate, CreateStmtContext *cxt, TypeName *ofTypename)
  {
  	HeapTuple	tuple;
  	Form_pg_type typ;
  	TupleDesc	tupdesc;
  	int			i;
  	Oid			ofTypeId;
  
  	AssertArg(ofTypename);
  
  	tuple = typenameType(NULL, ofTypename, NULL);
  	typ = (Form_pg_type) GETSTRUCT(tuple);
  	ofTypeId = HeapTupleGetOid(tuple);
  	ofTypename->typeOid = ofTypeId;		/* cached for later */
  
  	if (typ->typtype != TYPTYPE_COMPOSITE)
  		ereport(ERROR,
  				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
  				 errmsg("type %s is not a composite type",
  						format_type_be(ofTypeId))));
  
  	tupdesc = lookup_rowtype_tupdesc(ofTypeId, -1);
  	for (i = 0; i < tupdesc->natts; i++)
  	{
  		Form_pg_attribute attr = tupdesc->attrs[i];
  		ColumnDef  *n = makeNode(ColumnDef);
  
  		n->colname = pstrdup(NameStr(attr->attname));
  		n->typeName = makeTypeNameFromOid(attr->atttypid, attr->atttypmod);
  		n->constraints = NULL;
  		n->is_local = true;
  		n->is_from_type = true;
  		cxt->columns = lappend(cxt->columns, n);
  	}
  	DecrTupleDescRefCount(tupdesc);
  
  	ReleaseSysCache(tuple);
  }
  
  /*
   * chooseIndexName
   *
   * Compute name for an index.  This must match code in indexcmds.c.
   *
   * XXX this is inherently broken because the indexes aren't created
   * immediately, so we fail to resolve conflicts when the same name is
   * derived for multiple indexes.  However, that's a reasonably uncommon
   * situation, so we'll live with it for now.
   */
  static char *
  chooseIndexName(const RangeVar *relation, IndexStmt *index_stmt)
  {
  	Oid			namespaceId;
  	List	   *colnames;
  
  	namespaceId = RangeVarGetCreationNamespace(relation);
  	colnames = ChooseIndexColumnNames(index_stmt->indexParams);
  	return ChooseIndexName(relation->relname, namespaceId,
  						   colnames, index_stmt->excludeOpNames,
  						   index_stmt->primary, index_stmt->isconstraint);
  }
  
  /*
   * Generate an IndexStmt node using information from an already existing index
   * "source_idx".  Attribute numbers should be adjusted according to attmap.
   */
  static IndexStmt *
  generateClonedIndexStmt(CreateStmtContext *cxt, Relation source_idx,
  						AttrNumber *attmap)
  {
  	Oid			source_relid = RelationGetRelid(source_idx);
  	Form_pg_attribute *attrs = RelationGetDescr(source_idx)->attrs;
  	HeapTuple	ht_idxrel;
  	HeapTuple	ht_idx;
  	Form_pg_class idxrelrec;
  	Form_pg_index idxrec;
  	Form_pg_am	amrec;
  	oidvector  *indclass;
  	IndexStmt  *index;
  	List	   *indexprs;
  	ListCell   *indexpr_item;
  	Oid			indrelid;
  	int			keyno;
  	Oid			keycoltype;
  	Datum		datum;
  	bool		isnull;
  
  	/*
  	 * Fetch pg_class tuple of source index.  We can't use the copy in the
  	 * relcache entry because it doesn't include optional fields.
  	 */
  	ht_idxrel = SearchSysCache1(RELOID, ObjectIdGetDatum(source_relid));
  	if (!HeapTupleIsValid(ht_idxrel))
  		elog(ERROR, "cache lookup failed for relation %u", source_relid);
  	idxrelrec = (Form_pg_class) GETSTRUCT(ht_idxrel);
  
  	/* Fetch pg_index tuple for source index from relcache entry */
  	ht_idx = source_idx->rd_indextuple;
  	idxrec = (Form_pg_index) GETSTRUCT(ht_idx);
  	indrelid = idxrec->indrelid;
  
  	/* Fetch pg_am tuple for source index from relcache entry */
  	amrec = source_idx->rd_am;
  
  	/* Extract indclass from the pg_index tuple */
  	datum = SysCacheGetAttr(INDEXRELID, ht_idx,
  							Anum_pg_index_indclass, &isnull);
  	Assert(!isnull);
  	indclass = (oidvector *) DatumGetPointer(datum);
  
  	/* Begin building the IndexStmt */
  	index = makeNode(IndexStmt);
  	index->relation = cxt->relation;
  	index->accessMethod = pstrdup(NameStr(amrec->amname));
  	if (OidIsValid(idxrelrec->reltablespace))
  		index->tableSpace = get_tablespace_name(idxrelrec->reltablespace);
  	else
  		index->tableSpace = NULL;
  	index->unique = idxrec->indisunique;
  	index->primary = idxrec->indisprimary;
  	index->concurrent = false;
  
  	/*
  	 * We don't try to preserve the name of the source index; instead, just
  	 * let DefineIndex() choose a reasonable name.
  	 */
  	index->idxname = NULL;
  
  	/*
  	 * If the index is marked PRIMARY or has an exclusion condition, it's
  	 * certainly from a constraint; else, if it's not marked UNIQUE, it
  	 * certainly isn't.  If it is or might be from a constraint, we have to
  	 * fetch the pg_constraint record.
  	 */
  	if (index->primary || index->unique || idxrelrec->relhasexclusion)
  	{
  		Oid			constraintId = get_index_constraint(source_relid);
  
  		if (OidIsValid(constraintId))
  		{
  			HeapTuple	ht_constr;
  			Form_pg_constraint conrec;
  
  			ht_constr = SearchSysCache1(CONSTROID,
  										ObjectIdGetDatum(constraintId));
  			if (!HeapTupleIsValid(ht_constr))
  				elog(ERROR, "cache lookup failed for constraint %u",
  					 constraintId);
  			conrec = (Form_pg_constraint) GETSTRUCT(ht_constr);
  
  			index->isconstraint = true;
  			index->deferrable = conrec->condeferrable;
  			index->initdeferred = conrec->condeferred;
  
  			/* If it's an exclusion constraint, we need the operator names */
  			if (idxrelrec->relhasexclusion)
  			{
  				Datum	   *elems;
  				int			nElems;
  				int			i;
  
  				Assert(conrec->contype == CONSTRAINT_EXCLUSION);
  				/* Extract operator OIDs from the pg_constraint tuple */
  				datum = SysCacheGetAttr(CONSTROID, ht_constr,
  										Anum_pg_constraint_conexclop,
  										&isnull);
  				if (isnull)
  					elog(ERROR, "null conexclop for constraint %u",
  						 constraintId);
  
  				deconstruct_array(DatumGetArrayTypeP(datum),
  								  OIDOID, sizeof(Oid), true, 'i',
  								  &elems, NULL, &nElems);
  
  				for (i = 0; i < nElems; i++)
  				{
  					Oid			operid = DatumGetObjectId(elems[i]);
  					HeapTuple	opertup;
  					Form_pg_operator operform;
  					char	   *oprname;
  					char	   *nspname;
  					List	   *namelist;
  
  					opertup = SearchSysCache1(OPEROID,
  											  ObjectIdGetDatum(operid));
  					if (!HeapTupleIsValid(opertup))
  						elog(ERROR, "cache lookup failed for operator %u",
  							 operid);
  					operform = (Form_pg_operator) GETSTRUCT(opertup);
  					oprname = pstrdup(NameStr(operform->oprname));
  					/* For simplicity we always schema-qualify the op name */
  					nspname = get_namespace_name(operform->oprnamespace);
  					namelist = list_make2(makeString(nspname),
  										  makeString(oprname));
  					index->excludeOpNames = lappend(index->excludeOpNames,
  													namelist);
  					ReleaseSysCache(opertup);
  				}
  			}
  
  			ReleaseSysCache(ht_constr);
  		}
  		else
  			index->isconstraint = false;
  	}
  	else
  		index->isconstraint = false;
  
  	/* Get the index expressions, if any */
  	datum = SysCacheGetAttr(INDEXRELID, ht_idx,
  							Anum_pg_index_indexprs, &isnull);
  	if (!isnull)
  	{
  		char	   *exprsString;
  
  		exprsString = TextDatumGetCString(datum);
  		indexprs = (List *) stringToNode(exprsString);
  	}
  	else
  		indexprs = NIL;
  
  	/* Build the list of IndexElem */
  	index->indexParams = NIL;
  
  	indexpr_item = list_head(indexprs);
  	for (keyno = 0; keyno < idxrec->indnatts; keyno++)
  	{
  		IndexElem  *iparam;
  		AttrNumber	attnum = idxrec->indkey.values[keyno];
  		int16		opt = source_idx->rd_indoption[keyno];
  
  		iparam = makeNode(IndexElem);
  
  		if (AttributeNumberIsValid(attnum))
  		{
  			/* Simple index column */
  			char	   *attname;
  
  			attname = get_relid_attribute_name(indrelid, attnum);
  			keycoltype = get_atttype(indrelid, attnum);
  
  			iparam->name = attname;
  			iparam->expr = NULL;
  		}
  		else
  		{
  			/* Expressional index */
  			Node	   *indexkey;
  
  			if (indexpr_item == NULL)
  				elog(ERROR, "too few entries in indexprs list");
  			indexkey = (Node *) lfirst(indexpr_item);
  			indexpr_item = lnext(indexpr_item);
  
  			/* OK to modify indexkey since we are working on a private copy */
  			change_varattnos_of_a_node(indexkey, attmap);
  
  			iparam->name = NULL;
  			iparam->expr = indexkey;
  
  			keycoltype = exprType(indexkey);
  		}
  
  		/* Copy the original index column name */
  		iparam->indexcolname = pstrdup(NameStr(attrs[keyno]->attname));
  
  		/* Add the operator class name, if non-default */
  		iparam->opclass = get_opclass(indclass->values[keyno], keycoltype);
  
  		iparam->ordering = SORTBY_DEFAULT;
  		iparam->nulls_ordering = SORTBY_NULLS_DEFAULT;
  
  		/* Adjust options if necessary */
  		if (amrec->amcanorder)
  		{
  			/*
  			 * If it supports sort ordering, copy DESC and NULLS opts. Don't
  			 * set non-default settings unnecessarily, though, so as to
  			 * improve the chance of recognizing equivalence to constraint
  			 * indexes.
  			 */
  			if (opt & INDOPTION_DESC)
  			{
  				iparam->ordering = SORTBY_DESC;
  				if ((opt & INDOPTION_NULLS_FIRST) == 0)
  					iparam->nulls_ordering = SORTBY_NULLS_LAST;
  			}
  			else
  			{
  				if (opt & INDOPTION_NULLS_FIRST)
  					iparam->nulls_ordering = SORTBY_NULLS_FIRST;
  			}
  		}
  
  		index->indexParams = lappend(index->indexParams, iparam);
  	}
  
  	/* Copy reloptions if any */
  	datum = SysCacheGetAttr(RELOID, ht_idxrel,
  							Anum_pg_class_reloptions, &isnull);
  	if (!isnull)
  		index->options = untransformRelOptions(datum);
  
  	/* If it's a partial index, decompile and append the predicate */
  	datum = SysCacheGetAttr(INDEXRELID, ht_idx,
  							Anum_pg_index_indpred, &isnull);
  	if (!isnull)
  	{
  		char	   *pred_str;
  
  		/* Convert text string to node tree */
  		pred_str = TextDatumGetCString(datum);
  		index->whereClause = (Node *) stringToNode(pred_str);
  		/* Adjust attribute numbers */
  		change_varattnos_of_a_node(index->whereClause, attmap);
  	}
  
  	/* Clean up */
  	ReleaseSysCache(ht_idxrel);
  
  	return index;
  }
  
  /*
   * get_opclass			- fetch name of an index operator class
   *
   * If the opclass is the default for the given actual_datatype, then
   * the return value is NIL.
   */
  static List *
  get_opclass(Oid opclass, Oid actual_datatype)
  {
  	HeapTuple	ht_opc;
  	Form_pg_opclass opc_rec;
  	List	   *result = NIL;
  
  	ht_opc = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
  	if (!HeapTupleIsValid(ht_opc))
  		elog(ERROR, "cache lookup failed for opclass %u", opclass);
  	opc_rec = (Form_pg_opclass) GETSTRUCT(ht_opc);
  
  	if (GetDefaultOpClass(actual_datatype, opc_rec->opcmethod) != opclass)
  	{
  		/* For simplicity, we always schema-qualify the name */
  		char	   *nsp_name = get_namespace_name(opc_rec->opcnamespace);
  		char	   *opc_name = pstrdup(NameStr(opc_rec->opcname));
  
  		result = list_make2(makeString(nsp_name), makeString(opc_name));
  	}
  
  	ReleaseSysCache(ht_opc);
  	return result;
  }
  
  
  /*
   * transformIndexConstraints
   *		Handle UNIQUE, PRIMARY KEY, EXCLUDE constraints, which create indexes.
   *		We also merge in any index definitions arising from
   *		LIKE ... INCLUDING INDEXES.
   */
  static void
  transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
  {
  	IndexStmt  *index;
  	List	   *indexlist = NIL;
  	ListCell   *lc;
  
  	/*
  	 * Run through the constraints that need to generate an index. For PRIMARY
  	 * KEY, mark each column as NOT NULL and create an index. For UNIQUE or
  	 * EXCLUDE, create an index as for PRIMARY KEY, but do not insist on NOT
  	 * NULL.
  	 */
  	foreach(lc, cxt->ixconstraints)
  	{
  		Constraint *constraint = (Constraint *) lfirst(lc);
  
  		Assert(IsA(constraint, Constraint));
  		Assert(constraint->contype == CONSTR_PRIMARY ||
  			   constraint->contype == CONSTR_UNIQUE ||
  			   constraint->contype == CONSTR_EXCLUSION);
  
  		index = transformIndexConstraint(constraint, cxt);
  
  		indexlist = lappend(indexlist, index);
  	}
  
  	/* Add in any indexes defined by LIKE ... INCLUDING INDEXES */
  	foreach(lc, cxt->inh_indexes)
  	{
  		index = (IndexStmt *) lfirst(lc);
  
  		if (index->primary)
  		{
  			if (cxt->pkey != NULL)
  				ereport(ERROR,
  						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
  						 errmsg("multiple primary keys for table \"%s\" are not allowed",
  								cxt->relation->relname)));
  			cxt->pkey = index;
  		}
  
  		indexlist = lappend(indexlist, index);
  	}
  
  	/*
  	 * Scan the index list and remove any redundant index specifications. This
  	 * can happen if, for instance, the user writes UNIQUE PRIMARY KEY. A
  	 * strict reading of SQL92 would suggest raising an error instead, but
  	 * that strikes me as too anal-retentive. - tgl 2001-02-14
  	 *
  	 * XXX in ALTER TABLE case, it'd be nice to look for duplicate
  	 * pre-existing indexes, too.
  	 */
  	Assert(cxt->alist == NIL);
  	if (cxt->pkey != NULL)
  	{
  		/* Make sure we keep the PKEY index in preference to others... */
  		cxt->alist = list_make1(cxt->pkey);
  	}
  
  	foreach(lc, indexlist)
  	{
  		bool		keep = true;
  		ListCell   *k;
  
  		index = lfirst(lc);
  
  		/* if it's pkey, it's already in cxt->alist */
  		if (index == cxt->pkey)
  			continue;
  
  		foreach(k, cxt->alist)
  		{
  			IndexStmt  *priorindex = lfirst(k);
  
  			if (equal(index->indexParams, priorindex->indexParams) &&
  				equal(index->whereClause, priorindex->whereClause) &&
  				equal(index->excludeOpNames, priorindex->excludeOpNames) &&
  				strcmp(index->accessMethod, priorindex->accessMethod) == 0 &&
  				index->deferrable == priorindex->deferrable &&
  				index->initdeferred == priorindex->initdeferred)
  			{
  				priorindex->unique |= index->unique;
  
  				/*
  				 * If the prior index is as yet unnamed, and this one is
  				 * named, then transfer the name to the prior index. This
  				 * ensures that if we have named and unnamed constraints,
  				 * we'll use (at least one of) the names for the index.
  				 */
  				if (priorindex->idxname == NULL)
  					priorindex->idxname = index->idxname;
  				keep = false;
  				break;
  			}
  		}
  
  		if (keep)
  			cxt->alist = lappend(cxt->alist, index);
  	}
  }
  
  /*
   * transformIndexConstraint
   *		Transform one UNIQUE, PRIMARY KEY, or EXCLUDE constraint for
   *		transformIndexConstraints.
   */
  static IndexStmt *
  transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
  {
  	IndexStmt  *index;
  	ListCell   *lc;
  
  	index = makeNode(IndexStmt);
  
  	index->unique = (constraint->contype != CONSTR_EXCLUSION);
  	index->primary = (constraint->contype == CONSTR_PRIMARY);
  	if (index->primary)
  	{
  		if (cxt->pkey != NULL)
  			ereport(ERROR,
  					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
  			 errmsg("multiple primary keys for table \"%s\" are not allowed",
  					cxt->relation->relname)));
  		cxt->pkey = index;
  
  		/*
  		 * In ALTER TABLE case, a primary index might already exist, but
  		 * DefineIndex will check for it.
  		 */
  	}
  	index->isconstraint = true;
  	index->deferrable = constraint->deferrable;
  	index->initdeferred = constraint->initdeferred;
  
  	if (constraint->conname != NULL)
  		index->idxname = pstrdup(constraint->conname);
  	else
  		index->idxname = NULL;	/* DefineIndex will choose name */
  
  	index->relation = cxt->relation;
  	index->accessMethod = constraint->access_method ? constraint->access_method : DEFAULT_INDEX_TYPE;
  	index->options = constraint->options;
  	index->tableSpace = constraint->indexspace;
  	index->whereClause = constraint->where_clause;
  	index->indexParams = NIL;
  	index->excludeOpNames = NIL;
  	index->concurrent = false;
  
  	/*
  	 * If it's an EXCLUDE constraint, the grammar returns a list of pairs of
  	 * IndexElems and operator names.  We have to break that apart into
  	 * separate lists.
  	 */
  	if (constraint->contype == CONSTR_EXCLUSION)
  	{
  		foreach(lc, constraint->exclusions)
  		{
  			List	   *pair = (List *) lfirst(lc);
  			IndexElem  *elem;
  			List	   *opname;
  
  			Assert(list_length(pair) == 2);
  			elem = (IndexElem *) linitial(pair);
  			Assert(IsA(elem, IndexElem));
  			opname = (List *) lsecond(pair);
  			Assert(IsA(opname, List));
  
  			index->indexParams = lappend(index->indexParams, elem);
  			index->excludeOpNames = lappend(index->excludeOpNames, opname);
  		}
  
  		return index;
  	}
  
  	/*
  	 * For UNIQUE and PRIMARY KEY, we just have a list of column names.
  	 *
  	 * Make sure referenced keys exist.  If we are making a PRIMARY KEY index,
  	 * also make sure they are NOT NULL, if possible. (Although we could leave
  	 * it to DefineIndex to mark the columns NOT NULL, it's more efficient to
  	 * get it right the first time.)
  	 */
  	foreach(lc, constraint->keys)
  	{
  		char	   *key = strVal(lfirst(lc));
  		bool		found = false;
  		ColumnDef  *column = NULL;
  		ListCell   *columns;
  		IndexElem  *iparam;
  
  		foreach(columns, cxt->columns)
  		{
  			column = (ColumnDef *) lfirst(columns);
  			Assert(IsA(column, ColumnDef));
  			if (strcmp(column->colname, key) == 0)
  			{
  				found = true;
  				break;
  			}
  		}
  		if (found)
  		{
  			/* found column in the new table; force it to be NOT NULL */
  			if (constraint->contype == CONSTR_PRIMARY)
  				column->is_not_null = TRUE;
  		}
  		else if (SystemAttributeByName(key, cxt->hasoids) != NULL)
  		{
  			/*
  			 * column will be a system column in the new table, so accept it.
  			 * System columns can't ever be null, so no need to worry about
  			 * PRIMARY/NOT NULL constraint.
  			 */
  			found = true;
  		}
  		else if (cxt->inhRelations)
  		{
  			/* try inherited tables */
  			ListCell   *inher;
  
  			foreach(inher, cxt->inhRelations)
  			{
  				RangeVar   *inh = (RangeVar *) lfirst(inher);
  				Relation	rel;
  				int			count;
  
  				Assert(IsA(inh, RangeVar));
  				rel = heap_openrv(inh, AccessShareLock);
  				if (rel->rd_rel->relkind != RELKIND_RELATION)
  					ereport(ERROR,
  							(errcode(ERRCODE_WRONG_OBJECT_TYPE),
  						   errmsg("inherited relation \"%s\" is not a table",
  								  inh->relname)));
  				for (count = 0; count < rel->rd_att->natts; count++)
  				{
  					Form_pg_attribute inhattr = rel->rd_att->attrs[count];
  					char	   *inhname = NameStr(inhattr->attname);
  
  					if (inhattr->attisdropped)
  						continue;
  					if (strcmp(key, inhname) == 0)
  					{
  						found = true;
  
  						/*
  						 * We currently have no easy way to force an inherited
  						 * column to be NOT NULL at creation, if its parent
  						 * wasn't so already. We leave it to DefineIndex to
  						 * fix things up in this case.
  						 */
  						break;
  					}
  				}
  				heap_close(rel, NoLock);
  				if (found)
  					break;
  			}
  		}
  
  		/*
  		 * In the ALTER TABLE case, don't complain about index keys not
  		 * created in the command; they may well exist already. DefineIndex
  		 * will complain about them if not, and will also take care of marking
  		 * them NOT NULL.
  		 */
  		if (!found && !cxt->isalter)
  			ereport(ERROR,
  					(errcode(ERRCODE_UNDEFINED_COLUMN),
  					 errmsg("column \"%s\" named in key does not exist",
  							key)));
  
  		/* Check for PRIMARY KEY(foo, foo) */
  		foreach(columns, index->indexParams)
  		{
  			iparam = (IndexElem *) lfirst(columns);
  			if (iparam->name && strcmp(key, iparam->name) == 0)
  			{
  				if (index->primary)
  					ereport(ERROR,
  							(errcode(ERRCODE_DUPLICATE_COLUMN),
  							 errmsg("column \"%s\" appears twice in primary key constraint",
  									key)));
  				else
  					ereport(ERROR,
  							(errcode(ERRCODE_DUPLICATE_COLUMN),
  					errmsg("column \"%s\" appears twice in unique constraint",
  						   key)));
  			}
  		}
  
  		/* OK, add it to the index definition */
  		iparam = makeNode(IndexElem);
  		iparam->name = pstrdup(key);
  		iparam->expr = NULL;
  		iparam->indexcolname = NULL;
  		iparam->opclass = NIL;
  		iparam->ordering = SORTBY_DEFAULT;
  		iparam->nulls_ordering = SORTBY_NULLS_DEFAULT;
  		index->indexParams = lappend(index->indexParams, iparam);
  	}
  
  	return index;
  }
  
  /*
   * transformFKConstraints
   *		handle FOREIGN KEY constraints
   */
  static void
  transformFKConstraints(ParseState *pstate, CreateStmtContext *cxt,
  					   bool skipValidation, bool isAddConstraint)
  {
  	ListCell   *fkclist;
  
  	if (cxt->fkconstraints == NIL)
  		return;
  
  	/*
  	 * If CREATE TABLE or adding a column with NULL default, we can safely
  	 * skip validation of the constraint.
  	 */
  	if (skipValidation)
  	{
  		foreach(fkclist, cxt->fkconstraints)
  		{
  			Constraint *constraint = (Constraint *) lfirst(fkclist);
  
  			constraint->skip_validation = true;
  		}
  	}
  
  	/*
  	 * For CREATE TABLE or ALTER TABLE ADD COLUMN, gin up an ALTER TABLE ADD
  	 * CONSTRAINT command to execute after the basic command is complete. (If
  	 * called from ADD CONSTRAINT, that routine will add the FK constraints to
  	 * its own subcommand list.)
  	 *
  	 * Note: the ADD CONSTRAINT command must also execute after any index
  	 * creation commands.  Thus, this should run after
  	 * transformIndexConstraints, so that the CREATE INDEX commands are
  	 * already in cxt->alist.
  	 */
  	if (!isAddConstraint)
  	{
  		AlterTableStmt *alterstmt = makeNode(AlterTableStmt);
  
  		alterstmt->relation = cxt->relation;
  		alterstmt->cmds = NIL;
  		alterstmt->relkind = OBJECT_TABLE;
  
  		foreach(fkclist, cxt->fkconstraints)
  		{
  			Constraint *constraint = (Constraint *) lfirst(fkclist);
  			AlterTableCmd *altercmd = makeNode(AlterTableCmd);
  
  			altercmd->subtype = AT_ProcessedConstraint;
  			altercmd->name = NULL;
  			altercmd->def = (Node *) constraint;
  			alterstmt->cmds = lappend(alterstmt->cmds, altercmd);
  		}
  
  		cxt->alist = lappend(cxt->alist, alterstmt);
  	}
  }
  
  /*
   * transformIndexStmt - parse analysis for CREATE INDEX
   *
   * Note: this is a no-op for an index not using either index expressions or
   * a predicate expression.	There are several code paths that create indexes
   * without bothering to call this, because they know they don't have any
   * such expressions to deal with.
   */
  IndexStmt *
  transformIndexStmt(IndexStmt *stmt, const char *queryString)
  {
  	Relation	rel;
  	ParseState *pstate;
  	RangeTblEntry *rte;
  	ListCell   *l;
  
  	/*
  	 * We must not scribble on the passed-in IndexStmt, so copy it.  (This is
  	 * overkill, but easy.)
  	 */
  	stmt = (IndexStmt *) copyObject(stmt);
  
  	/*
  	 * Open the parent table with appropriate locking.	We must do this
  	 * because addRangeTableEntry() would acquire only AccessShareLock,
  	 * leaving DefineIndex() needing to do a lock upgrade with consequent risk
  	 * of deadlock.  Make sure this stays in sync with the type of lock
  	 * DefineIndex() wants.
  	 */
  	rel = heap_openrv(stmt->relation,
  				  (stmt->concurrent ? ShareUpdateExclusiveLock : ShareLock));
  
  	/* Set up pstate */
  	pstate = make_parsestate(NULL);
  	pstate->p_sourcetext = queryString;
  
  	/*
  	 * Put the parent table into the rtable so that the expressions can refer
  	 * to its fields without qualification.
  	 */
  	rte = addRangeTableEntry(pstate, stmt->relation, NULL, false, true);
  
  	/* no to join list, yes to namespaces */
  	addRTEtoQuery(pstate, rte, false, true, true);
  
  	/* take care of the where clause */
  	if (stmt->whereClause)
  		stmt->whereClause = transformWhereClause(pstate,
  												 stmt->whereClause,
  												 "WHERE");
  
  	/* take care of any index expressions */
  	foreach(l, stmt->indexParams)
  	{
  		IndexElem  *ielem = (IndexElem *) lfirst(l);
  
  		if (ielem->expr)
  		{
  			/* Extract preliminary index col name before transforming expr */
  			if (ielem->indexcolname == NULL)
  				ielem->indexcolname = FigureIndexColname(ielem->expr);
  
  			/* Now do parse transformation of the expression */
  			ielem->expr = transformExpr(pstate, ielem->expr);
  
  			/*
  			 * We check only that the result type is legitimate; this is for
  			 * consistency with what transformWhereClause() checks for the
  			 * predicate.  DefineIndex() will make more checks.
  			 */
  			if (expression_returns_set(ielem->expr))
  				ereport(ERROR,
  						(errcode(ERRCODE_DATATYPE_MISMATCH),
  						 errmsg("index expression cannot return a set")));
  		}
  	}
  
  	/*
  	 * Check that only the base rel is mentioned.
  	 */
  	if (list_length(pstate->p_rtable) != 1)
  		ereport(ERROR,
  				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
  				 errmsg("index expressions and predicates can refer only to the table being indexed")));
  
  	free_parsestate(pstate);
  
  	/* Close relation, but keep the lock */
  	heap_close(rel, NoLock);
  
  	return stmt;
  }
  
  
  /*
   * transformRuleStmt -
   *	  transform a CREATE RULE Statement. The action is a list of parse
   *	  trees which is transformed into a list of query trees, and we also
   *	  transform the WHERE clause if any.
   *
   * actions and whereClause are output parameters that receive the
   * transformed results.
   *
   * Note that we must not scribble on the passed-in RuleStmt, so we do
   * copyObject() on the actions and WHERE clause.
   */
  void
  transformRuleStmt(RuleStmt *stmt, const char *queryString,
  				  List **actions, Node **whereClause)
  {
  	Relation	rel;
  	ParseState *pstate;
  	RangeTblEntry *oldrte;
  	RangeTblEntry *newrte;
  
  	/*
  	 * To avoid deadlock, make sure the first thing we do is grab
  	 * AccessExclusiveLock on the target relation.	This will be needed by
  	 * DefineQueryRewrite(), and we don't want to grab a lesser lock
  	 * beforehand.
  	 */
  	rel = heap_openrv(stmt->relation, AccessExclusiveLock);
  
  	/* Set up pstate */
  	pstate = make_parsestate(NULL);
  	pstate->p_sourcetext = queryString;
  
  	/*
  	 * NOTE: 'OLD' must always have a varno equal to 1 and 'NEW' equal to 2.
  	 * Set up their RTEs in the main pstate for use in parsing the rule
  	 * qualification.
  	 */
  	oldrte = addRangeTableEntryForRelation(pstate, rel,
  										   makeAlias("old", NIL),
  										   false, false);
  	newrte = addRangeTableEntryForRelation(pstate, rel,
  										   makeAlias("new", NIL),
  										   false, false);
  	/* Must override addRangeTableEntry's default access-check flags */
  	oldrte->requiredPerms = 0;
  	newrte->requiredPerms = 0;
  
  	/*
  	 * They must be in the namespace too for lookup purposes, but only add the
  	 * one(s) that are relevant for the current kind of rule.  In an UPDATE
  	 * rule, quals must refer to OLD.field or NEW.field to be unambiguous, but
  	 * there's no need to be so picky for INSERT & DELETE.  We do not add them
  	 * to the joinlist.
  	 */
  	switch (stmt->event)
  	{
  		case CMD_SELECT:
  			addRTEtoQuery(pstate, oldrte, false, true, true);
  			break;
  		case CMD_UPDATE:
  			addRTEtoQuery(pstate, oldrte, false, true, true);
  			addRTEtoQuery(pstate, newrte, false, true, true);
  			break;
  		case CMD_INSERT:
  			addRTEtoQuery(pstate, newrte, false, true, true);
  			break;
  		case CMD_DELETE:
  			addRTEtoQuery(pstate, oldrte, false, true, true);
  			break;
  		default:
  			elog(ERROR, "unrecognized event type: %d",
  				 (int) stmt->event);
  			break;
  	}
  
  	/* take care of the where clause */
  	*whereClause = transformWhereClause(pstate,
  									  (Node *) copyObject(stmt->whereClause),
  										"WHERE");
  
  	if (list_length(pstate->p_rtable) != 2)		/* naughty, naughty... */
  		ereport(ERROR,
  				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
  				 errmsg("rule WHERE condition cannot contain references to other relations")));
  
  	/* aggregates not allowed (but subselects are okay) */
  	if (pstate->p_hasAggs)
  		ereport(ERROR,
  				(errcode(ERRCODE_GROUPING_ERROR),
  		   errmsg("cannot use aggregate function in rule WHERE condition")));
  	if (pstate->p_hasWindowFuncs)
  		ereport(ERROR,
  				(errcode(ERRCODE_WINDOWING_ERROR),
  			  errmsg("cannot use window function in rule WHERE condition")));
  
  	/*
  	 * 'instead nothing' rules with a qualification need a query rangetable so
  	 * the rewrite handler can add the negated rule qualification to the
  	 * original query. We create a query with the new command type CMD_NOTHING
  	 * here that is treated specially by the rewrite system.
  	 */
  	if (stmt->actions == NIL)
  	{
  		Query	   *nothing_qry = makeNode(Query);
  
  		nothing_qry->commandType = CMD_NOTHING;
  		nothing_qry->rtable = pstate->p_rtable;
  		nothing_qry->jointree = makeFromExpr(NIL, NULL);		/* no join wanted */
  
  		*actions = list_make1(nothing_qry);
  	}
  	else
  	{
  		ListCell   *l;
  		List	   *newactions = NIL;
  
  		/*
  		 * transform each statement, like parse_sub_analyze()
  		 */
  		foreach(l, stmt->actions)
  		{
  			Node	   *action = (Node *) lfirst(l);
  			ParseState *sub_pstate = make_parsestate(NULL);
  			Query	   *sub_qry,
  					   *top_subqry;
  			bool		has_old,
  						has_new;
  
  			/*
  			 * Since outer ParseState isn't parent of inner, have to pass down
  			 * the query text by hand.
  			 */
  			sub_pstate->p_sourcetext = queryString;
  
  			/*
  			 * Set up OLD/NEW in the rtable for this statement.  The entries
  			 * are added only to relnamespace, not varnamespace, because we
  			 * don't want them to be referred to by unqualified field names
  			 * nor "*" in the rule actions.  We decide later whether to put
  			 * them in the joinlist.
  			 */
  			oldrte = addRangeTableEntryForRelation(sub_pstate, rel,
  												   makeAlias("old", NIL),
  												   false, false);
  			newrte = addRangeTableEntryForRelation(sub_pstate, rel,
  												   makeAlias("new", NIL),
  												   false, false);
  			oldrte->requiredPerms = 0;
  			newrte->requiredPerms = 0;
  			addRTEtoQuery(sub_pstate, oldrte, false, true, false);
  			addRTEtoQuery(sub_pstate, newrte, false, true, false);
  
  			/* Transform the rule action statement */
  			top_subqry = transformStmt(sub_pstate,
  									   (Node *) copyObject(action));
  
  			/*
  			 * We cannot support utility-statement actions (eg NOTIFY) with
  			 * nonempty rule WHERE conditions, because there's no way to make
  			 * the utility action execute conditionally.
  			 */
  			if (top_subqry->commandType == CMD_UTILITY &&
  				*whereClause != NULL)
  				ereport(ERROR,
  						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
  						 errmsg("rules with WHERE conditions can only have SELECT, INSERT, UPDATE, or DELETE actions")));
  
  			/*
  			 * If the action is INSERT...SELECT, OLD/NEW have been pushed down
  			 * into the SELECT, and that's what we need to look at. (Ugly
  			 * kluge ... try to fix this when we redesign querytrees.)
  			 */
  			sub_qry = getInsertSelectQuery(top_subqry, NULL);
  
  			/*
  			 * If the sub_qry is a setop, we cannot attach any qualifications
  			 * to it, because the planner won't notice them.  This could
  			 * perhaps be relaxed someday, but for now, we may as well reject
  			 * such a rule immediately.
  			 */
  			if (sub_qry->setOperations != NULL && *whereClause != NULL)
  				ereport(ERROR,
  						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  						 errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
  
  			/*
  			 * Validate action's use of OLD/NEW, qual too
  			 */
  			has_old =
  				rangeTableEntry_used((Node *) sub_qry, PRS2_OLD_VARNO, 0) ||
  				rangeTableEntry_used(*whereClause, PRS2_OLD_VARNO, 0);
  			has_new =
  				rangeTableEntry_used((Node *) sub_qry, PRS2_NEW_VARNO, 0) ||
  				rangeTableEntry_used(*whereClause, PRS2_NEW_VARNO, 0);
  
  			switch (stmt->event)
  			{
  				case CMD_SELECT:
  					if (has_old)
  						ereport(ERROR,
  								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
  								 errmsg("ON SELECT rule cannot use OLD")));
  					if (has_new)
  						ereport(ERROR,
  								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
  								 errmsg("ON SELECT rule cannot use NEW")));
  					break;
  				case CMD_UPDATE:
  					/* both are OK */
  					break;
  				case CMD_INSERT:
  					if (has_old)
  						ereport(ERROR,
  								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
  								 errmsg("ON INSERT rule cannot use OLD")));
  					break;
  				case CMD_DELETE:
  					if (has_new)
  						ereport(ERROR,
  								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
  								 errmsg("ON DELETE rule cannot use NEW")));
  					break;
  				default:
  					elog(ERROR, "unrecognized event type: %d",
  						 (int) stmt->event);
  					break;
  			}
  
  			/*
  			 * For efficiency's sake, add OLD to the rule action's jointree
  			 * only if it was actually referenced in the statement or qual.
  			 *
  			 * For INSERT, NEW is not really a relation (only a reference to
  			 * the to-be-inserted tuple) and should never be added to the
  			 * jointree.
  			 *
  			 * For UPDATE, we treat NEW as being another kind of reference to
  			 * OLD, because it represents references to *transformed* tuples
  			 * of the existing relation.  It would be wrong to enter NEW
  			 * separately in the jointree, since that would cause a double
  			 * join of the updated relation.  It's also wrong to fail to make
  			 * a jointree entry if only NEW and not OLD is mentioned.
  			 */
  			if (has_old || (has_new && stmt->event == CMD_UPDATE))
  			{
  				/*
  				 * If sub_qry is a setop, manipulating its jointree will do no
  				 * good at all, because the jointree is dummy. (This should be
  				 * a can't-happen case because of prior tests.)
  				 */
  				if (sub_qry->setOperations != NULL)
  					ereport(ERROR,
  							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  							 errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
  				/* hack so we can use addRTEtoQuery() */
  				sub_pstate->p_rtable = sub_qry->rtable;
  				sub_pstate->p_joinlist = sub_qry->jointree->fromlist;
  				addRTEtoQuery(sub_pstate, oldrte, true, false, false);
  				sub_qry->jointree->fromlist = sub_pstate->p_joinlist;
  			}
  
  			newactions = lappend(newactions, top_subqry);
  
  			free_parsestate(sub_pstate);
  		}
  
  		*actions = newactions;
  	}
  
  	free_parsestate(pstate);
  
  	/* Close relation, but keep the exclusive lock */
  	heap_close(rel, NoLock);
  }
  
  
  /*
   * transformAlterTableStmt -
   *		parse analysis for ALTER TABLE
   *
   * Returns a List of utility commands to be done in sequence.  One of these
   * will be the transformed AlterTableStmt, but there may be additional actions
   * to be done before and after the actual AlterTable() call.
   */
  List *
  transformAlterTableStmt(AlterTableStmt *stmt, const char *queryString)
  {
  	Relation	rel;
  	ParseState *pstate;
  	CreateStmtContext cxt;
  	List	   *result;
  	List	   *save_alist;
  	ListCell   *lcmd,
  			   *l;
  	List	   *newcmds = NIL;
  	bool		skipValidation = true;
  	AlterTableCmd *newcmd;
  
  	/*
  	 * We must not scribble on the passed-in AlterTableStmt, so copy it. (This
  	 * is overkill, but easy.)
  	 */
  	stmt = (AlterTableStmt *) copyObject(stmt);
  
  	/*
  	 * Acquire exclusive lock on the target relation, which will be held until
  	 * end of transaction.	This ensures any decisions we make here based on
  	 * the state of the relation will still be good at execution. We must get
  	 * exclusive lock now because execution will; taking a lower grade lock
  	 * now and trying to upgrade later risks deadlock.
  	 */
  	rel = relation_openrv(stmt->relation, AccessExclusiveLock);
  
  	/* Set up pstate */
  	pstate = make_parsestate(NULL);
  	pstate->p_sourcetext = queryString;
  
  	cxt.stmtType = "ALTER TABLE";
  	cxt.relation = stmt->relation;
  	cxt.rel = rel;
  	cxt.inhRelations = NIL;
  	cxt.isalter = true;
  	cxt.hasoids = false;		/* need not be right */
  	cxt.columns = NIL;
  	cxt.ckconstraints = NIL;
  	cxt.fkconstraints = NIL;
  	cxt.ixconstraints = NIL;
  	cxt.inh_indexes = NIL;
  	cxt.blist = NIL;
  	cxt.alist = NIL;
  	cxt.pkey = NULL;
  
  	/*
  	 * The only subtypes that currently require parse transformation handling
  	 * are ADD COLUMN and ADD CONSTRAINT.  These largely re-use code from
  	 * CREATE TABLE.
  	 */
  	foreach(lcmd, stmt->cmds)
  	{
  		AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
  
  		switch (cmd->subtype)
  		{
  			case AT_AddColumn:
  			case AT_AddColumnToView:
  				{
  					ColumnDef  *def = (ColumnDef *) cmd->def;
  
  					Assert(IsA(def, ColumnDef));
  					transformColumnDefinition(pstate, &cxt, def);
  
  					/*
  					 * If the column has a non-null default, we can't skip
  					 * validation of foreign keys.
  					 */
  					if (def->raw_default != NULL)
  						skipValidation = false;
  
  					/*
  					 * All constraints are processed in other ways. Remove the
  					 * original list
  					 */
  					def->constraints = NIL;
  
  					newcmds = lappend(newcmds, cmd);
  					break;
  				}
  			case AT_AddConstraint:
  
  				/*
  				 * The original AddConstraint cmd node doesn't go to newcmds
  				 */
  				if (IsA(cmd->def, Constraint))
  				{
  					transformTableConstraint(pstate, &cxt,
  											 (Constraint *) cmd->def);
  					if (((Constraint *) cmd->def)->contype == CONSTR_FOREIGN)
  						skipValidation = false;
  				}
  				else
  					elog(ERROR, "unrecognized node type: %d",
  						 (int) nodeTag(cmd->def));
  				break;
  
  			case AT_ProcessedConstraint:
  
  				/*
  				 * Already-transformed ADD CONSTRAINT, so just make it look
  				 * like the standard case.
  				 */
  				cmd->subtype = AT_AddConstraint;
  				newcmds = lappend(newcmds, cmd);
  				break;
  
  			default:
  				newcmds = lappend(newcmds, cmd);
  				break;
  		}
  	}
  
  	/*
  	 * transformIndexConstraints wants cxt.alist to contain only index
  	 * statements, so transfer anything we already have into save_alist
  	 * immediately.
  	 */
  	save_alist = cxt.alist;
  	cxt.alist = NIL;
  
  	/* Postprocess index and FK constraints */
  	transformIndexConstraints(pstate, &cxt);
  
  	transformFKConstraints(pstate, &cxt, skipValidation, true);
  
  	/*
  	 * Push any index-creation commands into the ALTER, so that they can be
  	 * scheduled nicely by tablecmds.c.  Note that tablecmds.c assumes that
  	 * the IndexStmt attached to an AT_AddIndex subcommand has already been
  	 * through transformIndexStmt.
  	 */
  	foreach(l, cxt.alist)
  	{
  		Node	   *idxstmt = (Node *) lfirst(l);
  
  		Assert(IsA(idxstmt, IndexStmt));
  		newcmd = makeNode(AlterTableCmd);
  		newcmd->subtype = AT_AddIndex;
  		newcmd->def = (Node *) transformIndexStmt((IndexStmt *) idxstmt,
  												  queryString);
  		newcmds = lappend(newcmds, newcmd);
  	}
  	cxt.alist = NIL;
  
  	/* Append any CHECK or FK constraints to the commands list */
  	foreach(l, cxt.ckconstraints)
  	{
  		newcmd = makeNode(AlterTableCmd);
  		newcmd->subtype = AT_AddConstraint;
  		newcmd->def = (Node *) lfirst(l);
  		newcmds = lappend(newcmds, newcmd);
  	}
  	foreach(l, cxt.fkconstraints)
  	{
  		newcmd = makeNode(AlterTableCmd);
  		newcmd->subtype = AT_AddConstraint;
  		newcmd->def = (Node *) lfirst(l);
  		newcmds = lappend(newcmds, newcmd);
  	}
  
  	/* Close rel but keep lock */
  	relation_close(rel, NoLock);
  
  	/*
  	 * Output results.
  	 */
  	stmt->cmds = newcmds;
  
  	result = lappend(cxt.blist, stmt);
  	result = list_concat(result, cxt.alist);
  	result = list_concat(result, save_alist);
  
  	return result;
  }
  
  
  /*
   * Preprocess a list of column constraint clauses
   * to attach constraint attributes to their primary constraint nodes
   * and detect inconsistent/misplaced constraint attributes.
   *
   * NOTE: currently, attributes are only supported for FOREIGN KEY, UNIQUE,
   * and PRIMARY KEY constraints, but someday they ought to be supported
   * for other constraint types.
   */
  static void
  transformConstraintAttrs(ParseState *pstate, List *constraintList)
  {
  	Constraint *lastprimarycon = NULL;
  	bool		saw_deferrability = false;
  	bool		saw_initially = false;
  	ListCell   *clist;
  
  #define SUPPORTS_ATTRS(node)				\
  	((node) != NULL &&						\
  	 ((node)->contype == CONSTR_PRIMARY ||	\
  	  (node)->contype == CONSTR_UNIQUE ||	\
  	  (node)->contype == CONSTR_EXCLUSION || \
  	  (node)->contype == CONSTR_FOREIGN))
  
  	foreach(clist, constraintList)
  	{
  		Constraint *con = (Constraint *) lfirst(clist);
  
  		if (!IsA(con, Constraint))
  			elog(ERROR, "unrecognized node type: %d",
  				 (int) nodeTag(con));
  		switch (con->contype)
  		{
  			case CONSTR_ATTR_DEFERRABLE:
  				if (!SUPPORTS_ATTRS(lastprimarycon))
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("misplaced DEFERRABLE clause"),
  							 parser_errposition(pstate, con->location)));
  				if (saw_deferrability)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed"),
  							 parser_errposition(pstate, con->location)));
  				saw_deferrability = true;
  				lastprimarycon->deferrable = true;
  				break;
  
  			case CONSTR_ATTR_NOT_DEFERRABLE:
  				if (!SUPPORTS_ATTRS(lastprimarycon))
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("misplaced NOT DEFERRABLE clause"),
  							 parser_errposition(pstate, con->location)));
  				if (saw_deferrability)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed"),
  							 parser_errposition(pstate, con->location)));
  				saw_deferrability = true;
  				lastprimarycon->deferrable = false;
  				if (saw_initially &&
  					lastprimarycon->initdeferred)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE"),
  							 parser_errposition(pstate, con->location)));
  				break;
  
  			case CONSTR_ATTR_DEFERRED:
  				if (!SUPPORTS_ATTRS(lastprimarycon))
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("misplaced INITIALLY DEFERRED clause"),
  							 parser_errposition(pstate, con->location)));
  				if (saw_initially)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed"),
  							 parser_errposition(pstate, con->location)));
  				saw_initially = true;
  				lastprimarycon->initdeferred = true;
  
  				/*
  				 * If only INITIALLY DEFERRED appears, assume DEFERRABLE
  				 */
  				if (!saw_deferrability)
  					lastprimarycon->deferrable = true;
  				else if (!lastprimarycon->deferrable)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE"),
  							 parser_errposition(pstate, con->location)));
  				break;
  
  			case CONSTR_ATTR_IMMEDIATE:
  				if (!SUPPORTS_ATTRS(lastprimarycon))
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("misplaced INITIALLY IMMEDIATE clause"),
  							 parser_errposition(pstate, con->location)));
  				if (saw_initially)
  					ereport(ERROR,
  							(errcode(ERRCODE_SYNTAX_ERROR),
  							 errmsg("multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed"),
  							 parser_errposition(pstate, con->location)));
  				saw_initially = true;
  				lastprimarycon->initdeferred = false;
  				break;
  
  			default:
  				/* Otherwise it's not an attribute */
  				lastprimarycon = con;
  				/* reset flags for new primary node */
  				saw_deferrability = false;
  				saw_initially = false;
  				break;
  		}
  	}
  }
  
  /*
   * Special handling of type definition for a column
   */
  static void
  transformColumnType(ParseState *pstate, ColumnDef *column)
  {
  	/*
  	 * All we really need to do here is verify that the type is valid.
  	 */
  	Type		ctype = typenameType(pstate, column->typeName, NULL);
  
  	ReleaseSysCache(ctype);
  }
  
  
  /*
   * transformCreateSchemaStmt -
   *	  analyzes the CREATE SCHEMA statement
   *
   * Split the schema element list into individual commands and place
   * them in the result list in an order such that there are no forward
   * references (e.g. GRANT to a table created later in the list). Note
   * that the logic we use for determining forward references is
   * presently quite incomplete.
   *
   * SQL92 also allows constraints to make forward references, so thumb through
   * the table columns and move forward references to a posterior alter-table
   * command.
   *
   * The result is a list of parse nodes that still need to be analyzed ---
   * but we can't analyze the later commands until we've executed the earlier
   * ones, because of possible inter-object references.
   *
   * Note: this breaks the rules a little bit by modifying schema-name fields
   * within passed-in structs.  However, the transformation would be the same
   * if done over, so it should be all right to scribble on the input to this
   * extent.
   */
  List *
  transformCreateSchemaStmt(CreateSchemaStmt *stmt)
  {
  	CreateSchemaStmtContext cxt;
  	List	   *result;
  	ListCell   *elements;
  
  	cxt.stmtType = "CREATE SCHEMA";
  	cxt.schemaname = stmt->schemaname;
  	cxt.authid = stmt->authid;
  	cxt.sequences = NIL;
  	cxt.tables = NIL;
  	cxt.views = NIL;
  	cxt.indexes = NIL;
  	cxt.triggers = NIL;
  	cxt.grants = NIL;
  
  	/*
  	 * Run through each schema element in the schema element list. Separate
  	 * statements by type, and do preliminary analysis.
  	 */
  	foreach(elements, stmt->schemaElts)
  	{
  		Node	   *element = lfirst(elements);
  
  		switch (nodeTag(element))
  		{
  			case T_CreateSeqStmt:
  				{
  					CreateSeqStmt *elp = (CreateSeqStmt *) element;
  
  					setSchemaName(cxt.schemaname, &elp->sequence->schemaname);
  					cxt.sequences = lappend(cxt.sequences, element);
  				}
  				break;
  
  			case T_CreateStmt:
  				{
  					CreateStmt *elp = (CreateStmt *) element;
  
  					setSchemaName(cxt.schemaname, &elp->relation->schemaname);
  
  					/*
  					 * XXX todo: deal with constraints
  					 */
  					cxt.tables = lappend(cxt.tables, element);
  				}
  				break;
  
  			case T_ViewStmt:
  				{
  					ViewStmt   *elp = (ViewStmt *) element;
  
  					setSchemaName(cxt.schemaname, &elp->view->schemaname);
  
  					/*
  					 * XXX todo: deal with references between views
  					 */
  					cxt.views = lappend(cxt.views, element);
  				}
  				break;
  
  			case T_IndexStmt:
  				{
  					IndexStmt  *elp = (IndexStmt *) element;
  
  					setSchemaName(cxt.schemaname, &elp->relation->schemaname);
  					cxt.indexes = lappend(cxt.indexes, element);
  				}
  				break;
  
  			case T_CreateTrigStmt:
  				{
  					CreateTrigStmt *elp = (CreateTrigStmt *) element;
  
  					setSchemaName(cxt.schemaname, &elp->relation->schemaname);
  					cxt.triggers = lappend(cxt.triggers, element);
  				}
  				break;
  
  			case T_GrantStmt:
  				cxt.grants = lappend(cxt.grants, element);
  				break;
  
  			default:
  				elog(ERROR, "unrecognized node type: %d",
  					 (int) nodeTag(element));
  		}
  	}
  
  	result = NIL;
  	result = list_concat(result, cxt.sequences);
  	result = list_concat(result, cxt.tables);
  	result = list_concat(result, cxt.views);
  	result = list_concat(result, cxt.indexes);
  	result = list_concat(result, cxt.triggers);
  	result = list_concat(result, cxt.grants);
  
  	return result;
  }
  
  /*
   * setSchemaName
   *		Set or check schema name in an element of a CREATE SCHEMA command
   */
  static void
  setSchemaName(char *context_schema, char **stmt_schema_name)
  {
  	if (*stmt_schema_name == NULL)
  		*stmt_schema_name = context_schema;
  	else if (strcmp(context_schema, *stmt_schema_name) != 0)
  		ereport(ERROR,
  				(errcode(ERRCODE_INVALID_SCHEMA_DEFINITION),
  				 errmsg("CREATE specifies a schema (%s) "
  						"different from the one being created (%s)",
  						*stmt_schema_name, context_schema)));
  }
  