COMMENT(7) SQL Commands COMMENT(7)
COMMENT - define or change the comment of an object
TABLE object_name |
COLUMN table_name.column_name |
AGGREGATE agg_name (agg_type) |
CONSTRAINT constraint_name ON table_name |
DATABASE object_name |
DOMAIN object_name |
FUNCTION func_name (arg1_type, arg2_type, ...) |
INDEX object_name |
OPERATOR op (leftoperand_type, rightoperand_type) |
RULE rule_name ON table_name |
SCHEMA object_name |
SEQUENCE object_name |
TRIGGER trigger_name ON table_name |
TYPE object_name |
] IS 'text'
The name of the object to be be commented. Names of tables, aggregates, domains,
functions, indexes, operators, sequences, types, and views may be schema-qualified.
text The comment to add.
Message returned if the table is successfully commented.
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_descrip-
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.
Note: 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.
Attach a comment to the table mytable:
COMMENT ON TABLE mytable IS 'This is my table.';
Remove it again:
COMMENT ON TABLE mytable IS NULL;
Some more examples:
COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
COMMENT ON COLUMN my_table.my_field IS 'Employee ID number';
COMMENT ON DATABASE my_database IS 'Development Database';
COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee id';
COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two texts';
COMMENT ON OPERATOR ^ (NONE, text) IS 'This is a prefix operator on text';
COMMENT ON RULE my_rule ON my_table IS 'Logs UPDATES of employee records';
COMMENT ON SCHEMA my_schema IS 'Departmental data';
COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for R.I.';
COMMENT ON TYPE complex IS 'Complex Number datatype';
COMMENT ON VIEW my_view IS 'View of departmental costs';
There is no COMMENT in SQL92.
SQL - Language Statements 2002-11-22 COMMENT(7)