1COMMENT(7) SQL Commands COMMENT(7)
2
6 COMMENT - define or change the comment of an object
7
10 COMMENT ON
11 {
12 TABLE object_name |
13 COLUMN table_name.column_name |
14 AGGREGATE agg_name (agg_type [, ...] ) |
15 CAST (sourcetype AS targettype) |
16 CONSTRAINT constraint_name ON table_name |
17 CONVERSION object_name |
18 DATABASE object_name |
19 DOMAIN object_name |
20 FUNCTION func_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |
21 INDEX object_name |
22 LARGE OBJECT large_object_oid |
23 OPERATOR op (leftoperand_type, rightoperand_type) |
24 OPERATOR CLASS object_name USING index_method |
25 OPERATOR FAMILY object_name USING index_method |
26 [ PROCEDURAL ] LANGUAGE object_name |
27 ROLE object_name |
28 RULE rule_name ON table_name |
29 SCHEMA object_name |
30 SEQUENCE object_name |
31 TABLESPACE object_name |
32 TEXT SEARCH CONFIGURATION object_name |
33 TEXT SEARCH DICTIONARY object_name |
34 TEXT SEARCH PARSER object_name |
35 TEXT SEARCH TEMPLATE object_name |
36 TRIGGER trigger_name ON table_name |
37 TYPE object_name |
38 VIEW object_name
39 } IS 'text'
40
43 COMMENT stores a comment about a database object.
44 To modify a comment, issue a new COMMENT command for the same object.
46 Only one comment string is stored for each object. To remove a com‐
47 ment, write NULL in place of the text string. Comments are automati‐
48 cally dropped when the object is dropped.
49 Comments can be viewed using psql's \d family of commands. Other user
51 interfaces to retrieve comments can be built atop the same built-in
52 functions that psql uses, namely obj_description, col_description, and
53 shobj_description (see in the documentation).
54
56 object_name
57 table_name.column_name
59 agg_name
61 constraint_name
63 func_name
65 op
67 rule_name
69 trigger_name
71 The name of the object to be commented. Names of tables, aggre‐
72 gates, domains, functions, indexes, operators, operator classes,
73 operator families, sequences, text search objects, types, and
74 views can be schema-qualified.
75 agg_type
77 An input data type on which the aggregate function operates. To
78 reference a zero-argument aggregate function, write * in place
79 of the list of input data types.
80 sourcetype
82 The name of the source data type of the cast.
83 targettype
85 The name of the target data type of the cast.
86 argmode
88 The mode of a function argument: IN, OUT, INOUT, or VARIADIC.
89 If omitted, the default is IN. Note that COMMENT ON FUNCTION
90 does not actually pay any attention to OUT arguments, since only
91 the input arguments are needed to determine the function's iden‐
92 tity. So it is sufficient to list the IN, INOUT, and VARIADIC
93 arguments.
94 argname
96 The name of a function argument. Note that COMMENT ON FUNCTION
97 does not actually pay any attention to argument names, since
98 only the argument data types are needed to determine the func‐
99 tion's identity.
100 argtype
102 The data type(s) of the function's arguments (optionally schema-
103 qualified), if any.
104 large_object_oid
106 The OID of the large object.
107 PROCEDURAL
109 This is a noise word.
110 text The new comment, written as a string literal; or NULL to drop
112 the comment.
113
115 There is presently no security mechanism for comments: any user con‐
116 nected to a database can see all the comments for objects in that data‐
117 base (although only superusers can change comments for objects that
118 they don't own). For shared objects such as databases, roles, and
119 tablespaces comments are stored globally and any user connected to any
120 database can see all the comments for shared objects. Therefore, don't
121 put security-critical information in comments.
122
124 Attach a comment to the table mytable:
125 COMMENT ON TABLE mytable IS 'This is my table.';
127 Remove it again:
129 COMMENT ON TABLE mytable IS NULL;
131 Some more examples:
134 COMMENT ON AGGREGATE my_aggregate (double precision) IS 'Computes sample variance';
136 COMMENT ON CAST (text AS int4) IS 'Allow casts from text to int4';
137 COMMENT ON COLUMN my_table.my_column IS 'Employee ID number';
138 COMMENT ON CONVERSION my_conv IS 'Conversion to UTF8';
139 COMMENT ON DATABASE my_database IS 'Development Database';
140 COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
141 COMMENT ON FUNCTION my_function (timestamp) IS 'Returns Roman Numeral';
142 COMMENT ON INDEX my_index IS 'Enforces uniqueness on employee ID';
143 COMMENT ON LANGUAGE plpython IS 'Python support for stored procedures';
144 COMMENT ON LARGE OBJECT 346344 IS 'Planning document';
145 COMMENT ON OPERATOR ^ (text, text) IS 'Performs intersection of two texts';
146 COMMENT ON OPERATOR - (NONE, text) IS 'This is a prefix operator on text';
147 COMMENT ON OPERATOR CLASS int4ops USING btree IS '4 byte integer operators for btrees';
148 COMMENT ON OPERATOR FAMILY integer_ops USING btree IS 'all integer operators for btrees';
149 COMMENT ON ROLE my_role IS 'Administration group for finance tables';
150 COMMENT ON RULE my_rule ON my_table IS 'Logs updates of employee records';
151 COMMENT ON SCHEMA my_schema IS 'Departmental data';
152 COMMENT ON SEQUENCE my_sequence IS 'Used to generate primary keys';
153 COMMENT ON TABLE my_schema.my_table IS 'Employee Information';
154 COMMENT ON TABLESPACE my_tablespace IS 'Tablespace for indexes';
155 COMMENT ON TEXT SEARCH CONFIGURATION my_config IS 'Special word filtering';
156 COMMENT ON TEXT SEARCH DICTIONARY swedish IS 'Snowball stemmer for swedish language';
157 COMMENT ON TEXT SEARCH PARSER my_parser IS 'Splits text into words';
158 COMMENT ON TEXT SEARCH TEMPLATE snowball IS 'Snowball stemmer';
159 COMMENT ON TRIGGER my_trigger ON my_table IS 'Used for RI';
160 COMMENT ON TYPE complex IS 'Complex number data type';
161 COMMENT ON VIEW my_view IS 'View of departmental costs';
162
165 There is no COMMENT command in the SQL standard.
166SQL - Language Statements 2014-02-17 COMMENT(7)