anchor.diff:      ;
   
   alterTable
  -    : ALTER TABLE tableName alterClause_
  +    : ALTER TABLE tableName alterDefinitionClause_
       ;
   
   alterIndex
  
positive.code:     : UNIQUE? (CLUSTERED | NONCLUSTERED)?
      ;
  
  alterClause_
      : modifyColumnSpecification | addColumnSpecification | alterDrop | alterCheckConstraint | alterTrigger | alterSwitch | alterSet | alterTableOption | REBUILD
      ;
  
  
negative.code:     | SYSTEM_VERSIONING EQ_ ON (LP_ HISTORY_TABLE EQ_ tableName (COMMA_ DATA_CONSISTENCY_CHECK EQ_ (ON | OFF))? RP_)?
      ;
  
  tableExistClause_
      : (IF EXISTS)?
      ;
  
  indexExistClause_
      : (IF EXISTS)?
      ;
  
  
  
  