Comment On

Valid in: SQL, ESQL

The Comment On statement creates a comment on a table, view, or column.

Syntax

The Comment On statement has the following format:

[EXEC SQL] COMMENT ON
              TABLE [schema.]table_name | COLUMN [schema.]table_name.column_name
              IS remark_text

• table_name

  Specifies the table for which the constraint is defined.

• remark_text

  Defines the text of the comment.

  Limits: The maximum length for a comment is 1600 characters.

Description

The Comment On statement stores comments about a table, view, or column.

To display the comments, use the help comment statement.

To delete the comments, issue the comment on statement and specify an empty string (' '). Comments on tables and views are deleted when the table or view is dropped.

Embedded Usage

You cannot use host language variables in an embedded Comment On statement.

Permissions

You can only create comments on tables or views that you own.

Locking

The Comment On statement locks the iidbms_comment system catalog and takes an exclusive lock on the table on which the comment is being created.

Related Statements

Help

Examples: Comment On

The following examples store comments about a table:

1. Create a comment on the authors table.

   comment on table authors is
   'It was the best of times, it was the worst
   of times. It was...'

2. Delete comments on the authors table.

   comment on table authors is '';

3. Comment on column, name, in the authors table.

   comment on column authors.name is 'Call me Ishmael';