This page in other versions: 9.2 / 9.3 / 9.4 / 9.5 / current (9.6)  |  Development versions: devel  |  Unsupported versions: 7.1 / 7.2 / 7.3 / 7.4 / 8.0 / 8.1 / 8.2 / 8.3 / 8.4 / 9.0 / 9.1

COMMENT

Name

COMMENT  --  define or change the comment of an object

Synopsis

COMMENT ON
[
  [ DATABASE | INDEX | RULE | SEQUENCE | TABLE | TYPE | VIEW ] object_name |
  COLUMN table_name.column_name |
  AGGREGATE agg_name (agg_type) |
  FUNCTION func_name (arg1, arg2, ...) |
  OPERATOR op (leftoperand_type rightoperand_type) |
  TRIGGER trigger_name ON table_name
] IS 'text'
  

Inputs

object_name, table_name, column_name, agg_name, func_name, op, trigger_name

The name of the object to be be commented.

text

The comment to add.

Outputs

COMMENT

Message returned if the table is successfully commented.

Description

COMMENT stores a comment about a database object. Comments can be easily retrieved with psql's \dd, \d+, or \l+ commands. Other user interfaces to retrieve comments can be built atop the same built-in functions that psql uses, namely obj_description() and col_description().

To modify a comment, issue a new COMMENT command for the same object. Only one comment string is stored for each object. To remove a comment, write NULL in place of the text string. Comments are automatically dropped when the object is dropped.

It should be noted that there is presently no security mechanism for comments: any user connected to a database can see all the comments for objects in that database (although only superusers can change comments for objects that they don't own). Therefore, don't put security-critical information in comments.

Usage

Comment the table mytable:

COMMENT ON mytable IS 'This is my table.';
   

Some more examples:

COMMENT ON DATABASE my_database IS 'Development Database';
COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee id';
COMMENT ON RULE my_rule IS 'Logs UPDATES of employee records';
COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
COMMENT ON TABLE my_table IS 'Employee Information';
COMMENT ON TYPE my_type IS 'Complex Number support';
COMMENT ON VIEW my_view IS 'View of departmental costs';
COMMENT ON COLUMN my_table.my_field IS 'Employee ID number';
COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two text';
COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for R.I.';
   

Compatibility

SQL92

There is no COMMENT in SQL92.

Submit correction

If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.

Privacy Policy | About PostgreSQL
Copyright © 1996-2016 The PostgreSQL Global Development Group