COMMENT ON TABLE COLUMN

Adds, revises, or removes a table column comment. Each object can have one comment. Comments are stored in the system table COMMENTS.

Syntax

COMMENT ON COLUMN [[database.]schema.]table.column IS {'comment' | NULL}

Parameters

[database.]schema

Database and schema. The default schema is public. If you specify a database, it must be the current database.

table.column

The name of the table and column with which to associate the comment.

comment

Specifies the comment text to add. If a comment already exists for this column, this comment overwrites the previous comment.

Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and alerts the user with a message.

NULL

Removes an existing comment.

Privileges

Non-superuser: object owner

Examples

The following example adds a comment to the transaction_time column in the store_sales_fact table in the store schema:

=> COMMENT ON COLUMN store.store_sales_fact.transaction_time IS 'GMT';

The following example removes a comment from the transaction_time column in the store_sales_fact table in the store schema:

=> COMMENT ON COLUMN store.store_sales_fact.transaction_time IS NULL;