CommentStatement <- 'COMMENT' 'ON' CommentOnType ColumnReference 'IS' CommentValue


CommentOnType <- 'TABLE' / 'SEQUENCE' / 'FUNCTION' / ('MACRO' 'TABLE'?) / 'VIEW' / 'DATABASE' / 'INDEX' / 'SCHEMA' / 'TYPE' / 'COLUMN'
CommentValue <- 'NULL' / StringLiteral