1COMMENT(7) PostgreSQL 9.2.24 Documentation COMMENT(7)
2
6 COMMENT - define or change the comment of an object
7
9 COMMENT ON
10 {
11 AGGREGATE agg_name (agg_type [, ...] ) |
12 CAST (source_type AS target_type) |
13 COLLATION object_name |
14 COLUMN relation_name.column_name |
15 CONSTRAINT constraint_name ON table_name |
16 CONVERSION object_name |
17 DATABASE object_name |
18 DOMAIN object_name |
19 EXTENSION object_name |
20 FOREIGN DATA WRAPPER object_name |
21 FOREIGN TABLE object_name |
22 FUNCTION function_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |
23 INDEX object_name |
24 LARGE OBJECT large_object_oid |
25 OPERATOR operator_name (left_type, right_type) |
26 OPERATOR CLASS object_name USING index_method |
27 OPERATOR FAMILY object_name USING index_method |
28 [ PROCEDURAL ] LANGUAGE object_name |
29 ROLE object_name |
30 RULE rule_name ON table_name |
31 SCHEMA object_name |
32 SEQUENCE object_name |
33 SERVER object_name |
34 TABLE object_name |
35 TABLESPACE object_name |
36 TEXT SEARCH CONFIGURATION object_name |
37 TEXT SEARCH DICTIONARY object_name |
38 TEXT SEARCH PARSER object_name |
39 TEXT SEARCH TEMPLATE object_name |
40 TRIGGER trigger_name ON table_name |
41 TYPE object_name |
42 VIEW object_name
43 } IS 'text'
44
46 COMMENT stores a comment about a database object.
47 Only one comment string is stored for each object, so to modify a
49 comment, issue a new COMMENT command for the same object. To remove a
50 comment, write NULL in place of the text string. Comments are
51 automatically dropped when their object is dropped.
52 For most kinds of object, only the object's owner can set the comment.
54 Roles don't have owners, so the rule for COMMENT ON ROLE is that you
55 must be superuser to comment on a superuser role, or have the
56 CREATEROLE privilege to comment on non-superuser roles. Of course, a
57 superuser can comment on anything.
58 Comments can be viewed using psql's \d family of commands. Other user
60 interfaces to retrieve comments can be built atop the same built-in
61 functions that psql uses, namely obj_description, col_description, and
62 shobj_description (see Table 9.55, “Comment Information Functions”).
63
65 object_name, relation_name.column_name, agg_name, constraint_name,
66 function_name, operator_name, rule_name, trigger_name
67 The name of the object to be commented. Names of tables,
68 aggregates, collations, conversions, domains, foreign tables,
69 functions, indexes, operators, operator classes, operator families,
70 sequences, text search objects, types, and views can be
71 schema-qualified. When commenting on a column, relation_name must
72 refer to a table, view, composite type, or foreign table.
73 agg_type
75 An input data type on which the aggregate function operates. To
76 reference a zero-argument aggregate function, write * in place of
77 the list of input data types.
78 source_type
80 The name of the source data type of the cast.
81 target_type
83 The name of the target data type of the cast.
84 argmode
86 The mode of a function argument: IN, OUT, INOUT, or VARIADIC. If
87 omitted, the default is IN. Note that COMMENT ON FUNCTION does not
88 actually pay any attention to OUT arguments, since only the input
89 arguments are needed to determine the function's identity. So it is
90 sufficient to list the IN, INOUT, and VARIADIC arguments.
91 argname
93 The name of a function argument. Note that COMMENT ON FUNCTION does
94 not actually pay any attention to argument names, since only the
95 argument data types are needed to determine the function's
96 identity.
97 argtype
99 The data type(s) of the function's arguments (optionally
100 schema-qualified), if any.
101 large_object_oid
103 The OID of the large object.
104 left_type, right_type
106 The data type(s) of the operator's arguments (optionally
107 schema-qualified). Write NONE for the missing argument of a prefix
108 or postfix operator.
109 PROCEDURAL
111 This is a noise word.
112 text
114 The new comment, written as a string literal; or NULL to drop the
115 comment.
116
118 There is presently no security mechanism for viewing comments: any user
119 connected to a database can see all the comments for objects in that
120 database. For shared objects such as databases, roles, and tablespaces,
121 comments are stored globally so any user connected to any database in
122 the cluster can see all the comments for shared objects. Therefore,
123 don't put security-critical information in comments.
124
126 Attach a comment to the table mytable:
127 COMMENT ON TABLE mytable IS 'This is my table.';
129 Remove it again:
131 COMMENT ON TABLE mytable IS NULL;
133 Some more examples:
135 COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
137 COMMENT ON CAST (text AS int4) IS 'Allow casts from text to int4';
138 COMMENT ON COLLATION "fr_CA" IS 'Canadian French';
139 COMMENT ON COLUMN my_table.my_column IS 'Employee ID number';
140 COMMENT ON CONVERSION my_conv IS 'Conversion to UTF8';
141 COMMENT ON CONSTRAINT bar_col_cons ON bar IS 'Constrains column col';
142 COMMENT ON DATABASE my_database IS 'Development Database';
143 COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
144 COMMENT ON EXTENSION hstore IS 'implements the hstore data type';
145 COMMENT ON FOREIGN DATA WRAPPER mywrapper IS 'my foreign data wrapper';
146 COMMENT ON FOREIGN TABLE my_foreign_table IS 'Employee Information in other database';
147 COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
148 COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee ID';
149 COMMENT ON LANGUAGE plpython IS 'Python support for stored procedures';
150 COMMENT ON LARGE OBJECT 346344 IS 'Planning document';
151 COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two texts';
152 COMMENT ON OPERATOR - (NONE, integer) IS 'Unary minus';
153 COMMENT ON OPERATOR CLASS int4ops USING btree IS '4 byte integer operators for btrees';
154 COMMENT ON OPERATOR FAMILY integer_ops USING btree IS 'all integer operators for btrees';
155 COMMENT ON ROLE my_role IS 'Administration group for finance tables';
156 COMMENT ON RULE my_rule ON my_table IS 'Logs updates of employee records';
157 COMMENT ON SCHEMA my_schema IS 'Departmental data';
158 COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
159 COMMENT ON SERVER myserver IS 'my foreign server';
160 COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
161 COMMENT ON TABLESPACE my_tablespace IS 'Tablespace for indexes';
162 COMMENT ON TEXT SEARCH CONFIGURATION my_config IS 'Special word filtering';
163 COMMENT ON TEXT SEARCH DICTIONARY swedish IS 'Snowball stemmer for Swedish language';
164 COMMENT ON TEXT SEARCH PARSER my_parser IS 'Splits text into words';
165 COMMENT ON TEXT SEARCH TEMPLATE snowball IS 'Snowball stemmer';
166 COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for RI';
167 COMMENT ON TYPE complex IS 'Complex number data type';
168 COMMENT ON VIEW my_view IS 'View of departmental costs';
169
171 There is no COMMENT command in the SQL standard.
172PostgreSQL 9.2.24 2017-11-06 COMMENT(7)