1COMMENT(7) PostgreSQL 10.7 Documentation COMMENT(7)
2
6 COMMENT - define or change the comment of an object
7
9 COMMENT ON
10 {
11 ACCESS METHOD object_name |
12 AGGREGATE aggregate_name ( aggregate_signature ) |
13 CAST (source_type AS target_type) |
14 COLLATION object_name |
15 COLUMN relation_name.column_name |
16 CONSTRAINT constraint_name ON table_name |
17 CONSTRAINT constraint_name ON DOMAIN domain_name |
18 CONVERSION object_name |
19 DATABASE object_name |
20 DOMAIN object_name |
21 EXTENSION object_name |
22 EVENT TRIGGER object_name |
23 FOREIGN DATA WRAPPER object_name |
24 FOREIGN TABLE object_name |
25 FUNCTION function_name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] |
26 INDEX object_name |
27 LARGE OBJECT large_object_oid |
28 MATERIALIZED VIEW object_name |
29 OPERATOR operator_name (left_type, right_type) |
30 OPERATOR CLASS object_name USING index_method |
31 OPERATOR FAMILY object_name USING index_method |
32 POLICY policy_name ON table_name |
33 [ PROCEDURAL ] LANGUAGE object_name |
34 PUBLICATION object_name |
35 ROLE object_name |
36 RULE rule_name ON table_name |
37 SCHEMA object_name |
38 SEQUENCE object_name |
39 SERVER object_name |
40 STATISTICS object_name |
41 SUBSCRIPTION object_name |
42 TABLE object_name |
43 TABLESPACE object_name |
44 TEXT SEARCH CONFIGURATION object_name |
45 TEXT SEARCH DICTIONARY object_name |
46 TEXT SEARCH PARSER object_name |
47 TEXT SEARCH TEMPLATE object_name |
48 TRANSFORM FOR type_name LANGUAGE lang_name |
49 TRIGGER trigger_name ON table_name |
50 TYPE object_name |
51 VIEW object_name
52 } IS 'text'
53 where aggregate_signature is:
55 * |
57 [ argmode ] [ argname ] argtype [ , ... ] |
58 [ [ argmode ] [ argname ] argtype [ , ... ] ] ORDER BY [ argmode ] [ argname ] argtype [ , ... ]
59
61 COMMENT stores a comment about a database object.
62 Only one comment string is stored for each object, so to modify a
64 comment, issue a new COMMENT command for the same object. To remove a
65 comment, write NULL in place of the text string. Comments are
66 automatically dropped when their object is dropped.
67 For most kinds of object, only the object's owner can set the comment.
69 Roles don't have owners, so the rule for COMMENT ON ROLE is that you
70 must be superuser to comment on a superuser role, or have the
71 CREATEROLE privilege to comment on non-superuser roles. Likewise,
72 access methods don't have owners either; you must be superuser to
73 comment on an access method. Of course, a superuser can comment on
74 anything.
75 Comments can be viewed using psql's \d family of commands. Other user
77 interfaces to retrieve comments can be built atop the same built-in
78 functions that psql uses, namely obj_description, col_description, and
79 shobj_description (see Table 9.68).
80
82 object_name
83 relation_name.column_name
84 aggregate_name
85 constraint_name
86 function_name
87 operator_name
88 policy_name
89 rule_name
90 trigger_name
91 The name of the object to be commented. Names of tables,
92 aggregates, collations, conversions, domains, foreign tables,
93 functions, indexes, operators, operator classes, operator families,
94 sequences, statistics, text search objects, types, and views can be
95 schema-qualified. When commenting on a column, relation_name must
96 refer to a table, view, composite type, or foreign table.
97 table_name
99 domain_name
100 When creating a comment on a constraint, a trigger, a rule or a
101 policy these parameters specify the name of the table or domain on
102 which that object is defined.
103 source_type
105 The name of the source data type of the cast.
106 target_type
108 The name of the target data type of the cast.
109 argmode
111 The mode of a function or aggregate argument: IN, OUT, INOUT, or
112 VARIADIC. If omitted, the default is IN. Note that COMMENT does not
113 actually pay any attention to OUT arguments, since only the input
114 arguments are needed to determine the function's identity. So it is
115 sufficient to list the IN, INOUT, and VARIADIC arguments.
116 argname
118 The name of a function or aggregate argument. Note that COMMENT
119 does not actually pay any attention to argument names, since only
120 the argument data types are needed to determine the function's
121 identity.
122 argtype
124 The data type of a function or aggregate argument.
125 large_object_oid
127 The OID of the large object.
128 left_type
130 right_type
131 The data type(s) of the operator's arguments (optionally
132 schema-qualified). Write NONE for the missing argument of a prefix
133 or postfix operator.
134 PROCEDURAL
136 This is a noise word.
137 type_name
139 The name of the data type of the transform.
140 lang_name
142 The name of the language of the transform.
143 text
145 The new comment, written as a string literal; or NULL to drop the
146 comment.
147
149 There is presently no security mechanism for viewing comments: any user
150 connected to a database can see all the comments for objects in that
151 database. For shared objects such as databases, roles, and tablespaces,
152 comments are stored globally so any user connected to any database in
153 the cluster can see all the comments for shared objects. Therefore,
154 don't put security-critical information in comments.
155
157 Attach a comment to the table mytable:
158 COMMENT ON TABLE mytable IS 'This is my table.';
160 Remove it again:
162 COMMENT ON TABLE mytable IS NULL;
164 Some more examples:
166 COMMENT ON ACCESS METHOD rtree IS 'R-Tree access method';
168 COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
169 COMMENT ON CAST (text AS int4) IS 'Allow casts from text to int4';
170 COMMENT ON COLLATION "fr_CA" IS 'Canadian French';
171 COMMENT ON COLUMN my_table.my_column IS 'Employee ID number';
172 COMMENT ON CONVERSION my_conv IS 'Conversion to UTF8';
173 COMMENT ON CONSTRAINT bar_col_cons ON bar IS 'Constrains column col';
174 COMMENT ON CONSTRAINT dom_col_constr ON DOMAIN dom IS 'Constrains col of domain';
175 COMMENT ON DATABASE my_database IS 'Development Database';
176 COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
177 COMMENT ON EXTENSION hstore IS 'implements the hstore data type';
178 COMMENT ON FOREIGN DATA WRAPPER mywrapper IS 'my foreign data wrapper';
179 COMMENT ON FOREIGN TABLE my_foreign_table IS 'Employee Information in other database';
180 COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
181 COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee ID';
182 COMMENT ON LANGUAGE plpython IS 'Python support for stored procedures';
183 COMMENT ON LARGE OBJECT 346344 IS 'Planning document';
184 COMMENT ON MATERIALIZED VIEW my_matview IS 'Summary of order history';
185 COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two texts';
186 COMMENT ON OPERATOR - (NONE, integer) IS 'Unary minus';
187 COMMENT ON OPERATOR CLASS int4ops USING btree IS '4 byte integer operators for btrees';
188 COMMENT ON OPERATOR FAMILY integer_ops USING btree IS 'all integer operators for btrees';
189 COMMENT ON POLICY my_policy ON mytable IS 'Filter rows by users';
190 COMMENT ON ROLE my_role IS 'Administration group for finance tables';
191 COMMENT ON RULE my_rule ON my_table IS 'Logs updates of employee records';
192 COMMENT ON SCHEMA my_schema IS 'Departmental data';
193 COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
194 COMMENT ON SERVER myserver IS 'my foreign server';
195 COMMENT ON STATISTICS my_statistics IS 'Improves planner row estimations';
196 COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
197 COMMENT ON TABLESPACE my_tablespace IS 'Tablespace for indexes';
198 COMMENT ON TEXT SEARCH CONFIGURATION my_config IS 'Special word filtering';
199 COMMENT ON TEXT SEARCH DICTIONARY swedish IS 'Snowball stemmer for Swedish language';
200 COMMENT ON TEXT SEARCH PARSER my_parser IS 'Splits text into words';
201 COMMENT ON TEXT SEARCH TEMPLATE snowball IS 'Snowball stemmer';
202 COMMENT ON TRANSFORM FOR hstore LANGUAGE plpythonu IS 'Transform between hstore and Python dict';
203 COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for RI';
204 COMMENT ON TYPE complex IS 'Complex number data type';
205 COMMENT ON VIEW my_view IS 'View of departmental costs';
206
208 There is no COMMENT command in the SQL standard.
209PostgreSQL 10.7 2019 COMMENT(7)