anchor.diff:      : UNIQUE? (CLUSTERED | NONCLUSTERED)?
       ;
   
  -alterClause_
  +alterDefinitionClause_
       : modifyColumnSpecification | addColumnSpecification | alterDrop | alterCheckConstraint | alterTrigger | alterSwitch | alterSet | alterTableOption | REBUILD
       ;
   
  
positive.code:     | SYSTEM_VERSIONING EQ_ ON (LP_ HISTORY_TABLE EQ_ tableName (COMMA_ DATA_CONSISTENCY_CHECK EQ_ (ON | OFF))? RP_)?
      ;
  
  
  
  
  
negative.code:     ;
  
  dropTable
      : DROP TABLE tableExistClause_ tableNames
      ;
  
  dropIndex
      : DROP INDEX indexExistClause_ indexName ON tableName
      ;
  
  truncateTable
  