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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)

       COMMENT - define or change the comment of an object

         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'

       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.








              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.

       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)

       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';

       There is no COMMENT command in(1,8) the SQL standard.

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

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