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COMMENT(7)		PostgreSQL 9.6.3 Documentation		    COMMENT(7)

NAME
       COMMENT - define	or change the comment of an object

SYNOPSIS
       COMMENT ON
       {
	 ACCESS	METHOD object_name |
	 AGGREGATE aggregate_name ( aggregate_signature	) |
	 CAST (source_type AS target_type) |
	 COLLATION object_name |
	 COLUMN	relation_name.column_name |
	 CONSTRAINT constraint_name ON table_name |
	 CONSTRAINT constraint_name ON DOMAIN domain_name |
	 CONVERSION object_name	|
	 DATABASE object_name |
	 DOMAIN	object_name |
	 EXTENSION object_name |
	 EVENT TRIGGER object_name |
	 FOREIGN DATA WRAPPER object_name |
	 FOREIGN TABLE object_name |
	 FUNCTION function_name	( [ [ argmode ]	[ argname ] argtype [, ...] ] )	|
	 INDEX object_name |
	 LARGE OBJECT large_object_oid |
	 MATERIALIZED VIEW object_name |
	 OPERATOR operator_name	(left_type, right_type)	|
	 OPERATOR CLASS	object_name USING index_method |
	 OPERATOR FAMILY object_name USING index_method	|
	 POLICY	policy_name ON table_name |
	 [ PROCEDURAL ]	LANGUAGE object_name |
	 ROLE object_name |
	 RULE rule_name	ON table_name |
	 SCHEMA	object_name |
	 SEQUENCE object_name |
	 SERVER	object_name |
	 TABLE object_name |
	 TABLESPACE object_name	|
	 TEXT SEARCH CONFIGURATION object_name |
	 TEXT SEARCH DICTIONARY	object_name |
	 TEXT SEARCH PARSER object_name	|
	 TEXT SEARCH TEMPLATE object_name |
	 TRANSFORM FOR type_name LANGUAGE lang_name |
	 TRIGGER trigger_name ON table_name |
	 TYPE object_name |
	 VIEW object_name
       } IS 'text'

       where aggregate_signature is:

       * |
       [ argmode ] [ argname ] argtype [ , ... ] |
       [ [ argmode ] [ argname ] argtype [ , ... ] ] ORDER BY [	argmode	] [ argname ] argtype [	, ... ]

DESCRIPTION
       COMMENT stores a	comment	about a	database object.

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

       For most	kinds of object, only the object's owner can set the comment.
       Roles don't have	owners,	so the rule for	COMMENT	ON ROLE	is that	you
       must be superuser to comment on a superuser role, or have the
       CREATEROLE privilege to comment on non-superuser	roles. Likewise,
       access methods don't have owners	either;	you must be superuser to
       comment on an access method. Of course, a superuser can comment on
       anything.

       Comments	can be viewed using psql's \d family of	commands. 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 Table 9.67, "Comment Information Functions").

PARAMETERS
       object_name
       relation_name.column_name
       aggregate_name
       constraint_name
       function_name
       operator_name
       policy_name
       rule_name
       trigger_name
	   The name of the object to be	commented. Names of tables,
	   aggregates, collations, conversions,	domains, foreign tables,
	   functions, indexes, operators, operator classes, operator families,
	   sequences, text search objects, types, and views can	be
	   schema-qualified. When commenting on	a column, relation_name	must
	   refer to a table, view, composite type, or foreign table.

       table_name
       domain_name
	   When	creating a comment on a	constraint, a trigger, a rule or a
	   policy these	parameters specify the name of the table or domain on
	   which that object is	defined.

       source_type
	   The name of the source data type of the cast.

       target_type
	   The name of the target data type of the cast.

       argmode
	   The mode of a function or aggregate argument: IN, OUT, INOUT, or
	   VARIADIC. If	omitted, the default is	IN. Note that COMMENT does not
	   actually pay	any attention to OUT arguments,	since only the input
	   arguments are needed	to determine the function's identity. So it is
	   sufficient to list the IN, INOUT, and VARIADIC arguments.

       argname
	   The name of a function or aggregate argument. Note that COMMENT
	   does	not actually pay any attention to argument names, since	only
	   the argument	data types are needed to determine the function's
	   identity.

       argtype
	   The data type of a function or aggregate argument.

       large_object_oid
	   The OID of the large	object.

       left_type
       right_type
	   The data type(s) of the operator's arguments	(optionally
	   schema-qualified). Write NONE for the missing argument of a prefix
	   or postfix operator.

       PROCEDURAL
	   This	is a noise word.

       type_name
	   The name of the data	type of	the transform.

       lang_name
	   The name of the language of the transform.

       text
	   The new comment, written as a string	literal; or NULL to drop the
	   comment.

NOTES
       There is	presently no security mechanism	for viewing comments: any user
       connected to a database can see all the comments	for objects in that
       database. For shared objects such as databases, roles, and tablespaces,
       comments	are stored globally so any user	connected to any database in
       the cluster can see all the comments for	shared objects.	Therefore,
       don't put security-critical information in comments.

EXAMPLES
       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 ACCESS METHOD rtree IS 'R-Tree access method';
	   COMMENT ON AGGREGATE	my_aggregate (double precision)	IS 'Computes sample variance';
	   COMMENT ON CAST (text AS int4) IS 'Allow casts from text to int4';
	   COMMENT ON COLLATION	"fr_CA"	IS 'Canadian French';
	   COMMENT ON COLUMN my_table.my_column	IS 'Employee ID	number';
	   COMMENT ON CONVERSION my_conv IS 'Conversion	to UTF8';
	   COMMENT ON CONSTRAINT bar_col_cons ON bar IS	'Constrains column col';
	   COMMENT ON CONSTRAINT dom_col_constr	ON DOMAIN dom IS 'Constrains col of domain';
	   COMMENT ON DATABASE my_database IS 'Development Database';
	   COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
	   COMMENT ON EXTENSION	hstore IS 'implements the hstore data type';
	   COMMENT ON FOREIGN DATA WRAPPER mywrapper IS	'my foreign data wrapper';
	   COMMENT ON FOREIGN TABLE my_foreign_table IS	'Employee Information in other database';
	   COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
	   COMMENT ON INDEX my_index IS	'Enforces uniqueness on	employee ID';
	   COMMENT ON LANGUAGE plpython	IS 'Python support for stored procedures';
	   COMMENT ON LARGE OBJECT 346344 IS 'Planning document';
	   COMMENT ON MATERIALIZED VIEW	my_matview IS 'Summary of order	history';
	   COMMENT ON OPERATOR ^ (text,	text) IS 'Performs intersection	of two texts';
	   COMMENT ON OPERATOR - (NONE,	integer) IS 'Unary minus';
	   COMMENT ON OPERATOR CLASS int4ops USING btree IS '4 byte integer operators for btrees';
	   COMMENT ON OPERATOR FAMILY integer_ops USING	btree IS 'all integer operators	for btrees';
	   COMMENT ON POLICY my_policy ON mytable IS 'Filter rows by users';
	   COMMENT ON ROLE my_role IS 'Administration group for	finance	tables';
	   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 SERVER myserver IS 'my foreign server';
	   COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
	   COMMENT ON TABLESPACE my_tablespace IS 'Tablespace for indexes';
	   COMMENT ON TEXT SEARCH CONFIGURATION	my_config IS 'Special word filtering';
	   COMMENT ON TEXT SEARCH DICTIONARY swedish IS	'Snowball stemmer for Swedish language';
	   COMMENT ON TEXT SEARCH PARSER my_parser IS 'Splits text into	words';
	   COMMENT ON TEXT SEARCH TEMPLATE snowball IS 'Snowball stemmer';
	   COMMENT ON TRANSFORM	FOR hstore LANGUAGE plpythonu IS 'Transform between hstore and Python dict';
	   COMMENT ON TRIGGER my_trigger ON my_table IS	'Used for RI';
	   COMMENT ON TYPE complex IS 'Complex number data type';
	   COMMENT ON VIEW my_view IS 'View of departmental costs';

COMPATIBILITY
       There is	no COMMENT command in the SQL standard.

PostgreSQL 9.6.3		     2017			    COMMENT(7)

NAME | SYNOPSIS | DESCRIPTION | PARAMETERS | NOTES | EXAMPLES | COMPATIBILITY

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