[IMPALA-5614] Add COMMENT ON syntax to support comments on all objects

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 2.9.0
• Fix Version/s: Impala 3.1.0
• Component/s: Frontend
• Labels: newbie sql-language
• Epic Color: ghx-label-4
• Assignee: Fredy Wijaya
• Reporter: Greg Rahn
• Created: 05/Jul/17 18:43
• Updated: 09/Nov/18 16:01
• Resolved: 09/Nov/18 16:01

Description

The current SQL grammar (v2.9) allows for comments on objects at creation time but does not allow for modification post-fact. Postgres and others support the COMMENT ON syntax although it is not part of the ANSI standard.

For example:

COMMENT ON DATABASE my_database IS 'Development Database';
COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
COMMENT ON COLUMN my_table.my_column IS 'Employee ID number';
COMMENT ON VIEW my_view IS 'View of departmental costs';
COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';

COMMENT ON DATABASE my_database IS NULL; -- to remove a comment

References:

• Postgres
• Vertica
• Netezza
• Redshift
• DB2
• Oracle
• Snowflake

Issue Links

• is duplicated by: IMPALA-6236 Enhance alter view command to add or change comments in columns

Sub-Tasks

• Implement COMMENT ON DATABASE: Resolved
• Implement COMMENT ON TABLE/VIEW: Resolved
• Implement COMMENT ON COLUMN: Resolved
• Impala 3.1 Doc: Doc the COMMENT ON statements: Closed