anchor.diff:  import DataType,Keyword,Symbol;
   
   ID: 
  -    (BACK_QUOTA?[a-zA-Z_$][a-zA-Z0-9_$]* BACK_QUOTA? DOT)?
  -    (BACK_QUOTA?[a-zA-Z_$][a-zA-Z0-9_$]* BACK_QUOTA?)
  -    |[a-zA-Z_$0-9]+ DOT ASTERISK
  +    (BQ_?[a-zA-Z_$][a-zA-Z0-9_$]* BQ_? DOT)?
  +    (BQ_?[a-zA-Z_$][a-zA-Z0-9_$]* BQ_?)
  +    | [a-zA-Z_$0-9]+ DOT ASTERISK
       ;
   
   schemaName: ID;
   tableName: ID;
  -columnName: ID; 
  +columnName: ID;
   tablespaceName: ID;
   collationName: STRING | ID;
   indexName: ID;
  
positive.code:     : IF NOT EXISTS;
  
  dataTypeLength
      : LEFT_PAREN (NUMBER (COMMA NUMBER)?)? RIGHT_PAREN
      ;
  
  nullNotnull
  
negative.code:     | bitExpr ASTERISK bitExpr
      | bitExpr SLASH bitExpr
      | bitExpr MOD bitExpr
      | bitExpr MOD_ bitExpr
      | bitExpr BIT_EXCLUSIVE_OR bitExpr
      //| bitExpr '+' interval_expr
      //| bitExpr '-' interval_expr
      | simpleExpr
      ;
  
  simpleExpr
      : functionCall
      | liter
  