anchor.diff:      : RENAME CONSTRAINT constraintName TO constraintName
       ;
   
  +storageParameterWithValue
  +    : storageParameter EQ_OR_ASSIGN simpleExpr
  +    ;
  +
  +storageParameter
  +    : ID
  +    ;
  +
   alterTableNameExists
       : alterTableOp (IF EXISTS)? tableName
       ;
  
positive.code:     ;
       
  modifyColumn
      : alterColumn (SET DATA)? TYPE dataType collateClause? (USING simpleExpr)?
      ;
       
  alterColumn     
      : ALTER COLUMN? columnName
      ;
       
  alterTableAddConstraint       
  
negative.code: import PostgreKeyword, DataType, Keyword, PostgreBase, BaseRule, Symbol;
  
  alterTable
      : alterTableNameWithAsterisk (alterTableActions | renameColumn | renameConstraint)
      | alterTableNameExists renameTable
      ;
  
  