COMMENT ON Statement (comment_on_statement)

The COMMENT ON statement (comment_on_statement) creates, alters or deletes a comment for a database object stored in the database catalog.

Structure

Syntax Syntax

<comment_on_statement> ::=
  COMMENT ON <object_spec> IS <comment>

<object_spec> ::=
  see explanation below

<comment> ::=
  <string_literal>
| <parameter_name>

End of the code.

Explanation

Comments can be specified for the following database objects:

COMMENT_ON Statement
<object_spec> ::=	Explanation
`COLUMN <`table_name`>.<`column_name`>`	The column must exist in the specified table. The current database user must be the owner of the table. The comment for this column can be requested by selecting the system table DOMAIN.COLUMNS.
`DBPROC[EDURE] <`dbproc_name`>`	`dbproc_name` must identify an existing database procedure, the owner of which is the current database user. A comment is stored for the DB procedure. The comment can be requested by selecting the system table DOMAIN.DBPROCEDURES.
`DOMAIN <`domain_name`>`	`domain_name` must specify a domain of the current database user. The comment for this domain can be requested by selecting the system table DOMAIN.DOMAINS.
`FOREIGN KEY <table_name>.<`referential_constraint_name`>`	`referential_constraint_name` must specify a referential CONSTRAINT definition for the specified table. The current database user must be the owner of the table. The comment for this referential `CONSTRAINT` definition can be requested by selecting the system table DOMAIN.FOREIGNKEYS.
`INDEX <`index_name`> ON <table_name>`	`index_name` must specify an index of the specified table. The current database user must be the owner of the table. The comment for this index can be requested by selecting the system table DOMAIN.INDEXES.
`SEQUENCE <`sequence_name`>`	An existing sequence must be specified using sequence_name. The current database user must be the owner of the sequence. The comment for this sequence can be requested by selecting the system table DOMAIN.SEQUENCES.
`[PUBLIC] SYNONYM <`synonym_name`>`	`synonym_name` must specify a synonym of the current database user. If `PUBLIC` is specified, the synonym must have the `PUBLIC` attribute. The comment for this synonym can be requested by selecting the system table DOMAIN.SYNONYMS.
`TABLE <table_name>`	The specified table must identify a base or view table of the current user that is not a temporary table. The current database user must be the owner of the table. The comment for this table can be requested by selecting the system table DOMAIN.TABLES.
`TRIGGER <table_name>.<`trigger_name`>`	The specified trigger name must identify a trigger of the specified table. The current database user must be the owner of the table. A comment is stored for the trigger. The comment can be retrieved by selecting the system table DOMAIN.TRIGGERS.
`USER <`user_name`>`	The specified database user must identify an existing user whose owner is the current database user. The comment for this database user can be requested by selecting the system table DOMAIN.USERS.
`USERGROUP <`usergroup_name`>`	The specified user group must identify an existing user group whose owner is the current database user. The comment for this user group can be requested by selecting the system table DOMAIN.USERS.
`<`parameter_name`>`	The corresponding variable must contain one of the values listed in the table. The values must be enclosed by inverted commas. Example of a corresponding variable: `'COLUMN <table_name>.<column_name>'`