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comment(7) - COMMENT - define or change the comment of an object - man 7 comment

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COMMENT(7)                       SQL Commands                       COMMENT(7)



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) |
         CONSTRAINT constraint_name ON table_name |
         DATABASE object_name |
         DOMAIN object_name |
         FUNCTION func_name (arg1_type, arg2_type, ...) |
         INDEX object_name |
         OPERATOR op (leftoperand_type, rightoperand_type) |
         RULE rule_name ON table_name |
         SCHEMA object_name |
         SEQUENCE 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.  Comments can be eas-
       ily 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 and col_description.

       To modify a comment, issue a new COMMENT command for the  same  object.
       Only  one  comment  string(3,n) is stored for each object.  To remove a com-
       ment, write(1,2) NULL in(1,8) place of the text string.  Comments  are  automati-
       cally dropped when the object is dropped.

PARAMETERS
       object_name

       table_name.column_name

       aggname

       constraint_name

       func_name

       op

       rule_name

       trigger_name
              The  name  of  the  object  to be be commented. Names of tables,
              aggregates, domains, functions, indexes,  operators,  sequences,
              types, and views may be schema-qualified.

       text   The new comment.

NOTES
       There  is  presently  no security mechanism for comments: any user con-
       nected to a database can see all the comments for objects in(1,8) that data-
       base  (although  only  superusers  can change comments for objects that
       they don't own). Therefore, don't put security-critical information  in(1,8)
       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 COLUMN my_table.my_column IS 'Employee ID number';
       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 OPERATOR ^ (text, text) IS 'Performs intersection of two texts';
       COMMENT ON OPERATOR ^ (NONE, text) IS 'This is a prefix operator on text';
       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 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(1,8) the SQL standard.



SQL - Language Statements         2003-11-02                        COMMENT(7)

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