Inserts or replaces a comment string on a database object.
stringfor the specified object is stored in the data dictionary. Any previously defined comment for the object is replaced by the new.
A comment can only be stored on a system database object by the creator of the object.
A comment can only be stored on a private database object by the creator of the schema to which the object belongs.
See The Data Dictionary for a description of system and private database objects.
Only users with
SHADOWprivilege may store a comment on a shadow.
A comment string may have a maximum length of 254 characters and must be enclosed in string delimiters.
Comments may not be altered or dropped directly. However, since the
COMMENTstatement replaces any existing comment with the new text, a comment may be altered simply by issuing a new
COMMENTstatement. A comment may be effectively dropped by issuing a
COMMENTstatement with an empty string.
When a comment is written for a column, the column name must be qualified by a table-name or a view-name in the form
ExampleCOMMENT ON TABLE countries IS 'All countries we ship to';
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