Provided by: postgresql-client-8.2_8.2.7-1_i386 bug

NAME

       COMMENT - define or change the comment of an object

SYNOPSIS

       COMMENT ON
       {
         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 |
         VIEW object_name
       } IS ’text’

DESCRIPTION

       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).

PARAMETERS

       object_name

       table_name.column_name

       agg_name

       constraint_name

       func_name

       op

       rule_name

       trigger_name
              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.

       agg_type
              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.

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

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

       argmode
              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 function’s identity.
              So it is sufficient to list the IN and INOUT arguments.

       argname
              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
              function’s identity.

       argtype
              The data type(s) of the function’s arguments (optionally schema-
              qualified), if any.

       large_object_oid
              The OID of the large object.

       PROCEDURAL
              This is a noise word.

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

NOTES

       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  don’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, 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 AGGREGATE my_aggregate (double precision) IS ’Computes sample variance’;
       COMMENT ON CAST (text AS int4) IS ’Allow casts from text to int4’;
       COMMENT ON COLUMN my_table.my_column IS ’Employee ID number’;
       COMMENT ON CONVERSION my_conv IS ’Conversion to UTF8’;
       COMMENT ON DATABASE my_database IS ’Development Database’;
       COMMENT ON DOMAIN my_domain IS ’Email Address Domain’;
       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 OPERATOR ^ (text, text) IS ’Performs intersection of two texts’;
       COMMENT ON OPERATOR - (NONE, text) IS ’This is a prefix operator on text’;
       COMMENT ON OPERATOR CLASS int4ops USING btree IS ’4 byte integer operators for btrees’;
       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 TABLE my_schema.my_table IS ’Employee Information’;
       COMMENT ON TABLESPACE my_tablespace IS ’Tablespace for indexes’;
       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.