Provided by: postgresql-client-8.2_8.2.7-1_i386
COMMENT - define or change the comment of an object
TABLE object_name |
COLUMN table_name.column_name |
AGGREGATE agg_name (agg_type [, ...] ) |
CAST (sourcetype AS targettype) |
CONSTRAINT constraint_name ON table_name |
CONVERSION object_name |
DATABASE object_name |
DOMAIN object_name |
FUNCTION func_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |
INDEX object_name |
LARGE OBJECT large_object_oid |
OPERATOR op (leftoperand_type, rightoperand_type) |
OPERATOR CLASS object_name USING index_method |
[ PROCEDURAL ] LANGUAGE object_name |
ROLE object_name |
RULE rule_name ON table_name |
SCHEMA object_name |
SEQUENCE object_name |
TABLESPACE object_name |
TRIGGER trigger_name ON table_name |
TYPE object_name |
} IS â€™textâ€™
COMMENT stores a comment about a database object.
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.
Comments can be easily retrieved with the psql commands \dd, \d+, and
\l+. Other user interfaces to retrieve comments can be built atop the
same built-in functions that psql uses, namely obj_description,
col_description, and shobj_description (see in the documentation).
The name of the object to be commented. Names of tables,
aggregates, domains, functions, indexes, operators, operator
classes, sequences, types, and views may be schema-qualified.
An input data type on which the aggregate function operates. To
reference a zero-argument aggregate function, write * in place
of the list of input data types.
The name of the source data type of the cast.
The name of the target data type of the cast.
The mode of a function argument: either IN, OUT, or INOUT. If
omitted, the default is IN. Note that COMMENT ON FUNCTION does
not actually pay any attention to OUT arguments, since only the
input arguments are needed to determine the functionâ€™s identity.
So it is sufficient to list the IN and INOUT arguments.
The name of a function argument. Note that COMMENT ON FUNCTION
does not actually pay any attention to argument names, since
only the argument data types are needed to determine the
The data type(s) of the functionâ€™s arguments (optionally schema-
qualified), if any.
The OID of the large object.
This is a noise word.
text The new comment, written as a string literal; or NULL to drop
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 donâ€™t own). For shared objects such as databases, roles, and
tablespaces comments are stored globally and any user connected to any
database can see all the comments for shared objects. Therefore, donâ€™t
put security-critical information in comments.
Attach a comment to the table mytable:
COMMENT ON TABLE mytable IS â€™This is my table.â€™;
Remove it again:
COMMENT ON TABLE mytable IS NULL;
Some more examples:
COMMENT ON AGGREGATE my_aggregate (double precision) IS â€™Computes sample varianceâ€™;
COMMENT ON CAST (text AS int4) IS â€™Allow casts from text to int4â€™;
COMMENT ON COLUMN my_table.my_column IS â€™Employee ID numberâ€™;
COMMENT ON CONVERSION my_conv IS â€™Conversion to UTF8â€™;
COMMENT ON DATABASE my_database IS â€™Development Databaseâ€™;
COMMENT ON DOMAIN my_domain IS â€™Email Address Domainâ€™;
COMMENT ON FUNCTION my_function (timestamp) IS â€™Returns Roman Numeralâ€™;
COMMENT ON INDEX my_index IS â€™Enforces uniqueness on employee IDâ€™;
COMMENT ON LANGUAGE plpython IS â€™Python support for stored proceduresâ€™;
COMMENT ON LARGE OBJECT 346344 IS â€™Planning documentâ€™;
COMMENT ON OPERATOR ^ (text, text) IS â€™Performs intersection of two textsâ€™;
COMMENT ON OPERATOR - (NONE, text) IS â€™This is a prefix operator on textâ€™;
COMMENT ON OPERATOR CLASS int4ops USING btree IS â€™4 byte integer operators for btreesâ€™;
COMMENT ON ROLE my_role IS â€™Administration group for finance tablesâ€™;
COMMENT ON RULE my_rule ON my_table IS â€™Logs updates of employee recordsâ€™;
COMMENT ON SCHEMA my_schema IS â€™Departmental dataâ€™;
COMMENT ON SEQUENCE my_sequence IS â€™Used to generate primary keysâ€™;
COMMENT ON TABLE my_schema.my_table IS â€™Employee Informationâ€™;
COMMENT ON TABLESPACE my_tablespace IS â€™Tablespace for indexesâ€™;
COMMENT ON TRIGGER my_trigger ON my_table IS â€™Used for RIâ€™;
COMMENT ON TYPE complex IS â€™Complex number data typeâ€™;
COMMENT ON VIEW my_view IS â€™View of departmental costsâ€™;
There is no COMMENT command in the SQL standard.