COMMENT (Returning Form) | Teradata Vantage - COMMENT (Returning Form) - Advanced SQL Engine - Teradata Database

Purpose

Returns the comment (if any) that belongs to an object.

Invocation

Executable.

Embedded SQL only.

Syntax

COMMENT [ON] object_kind object_reference
  INTO [:] host_variable_name
  [ [ INDICATOR ] :host_indicator_name ]

object_kind

One of these objects:

• COLUMN
• DATABASE
• FUNCTION
• MACRO
• PROCEDURE
• PROFILE
• ROLE
• TABLE
• TRIGGER
• USER
• VIEW

object_reference

One of these object references:

• column name
• database name
• macro name
• procedure name
• profile name
• role name
• table name
• trigger name
• user name
• user-defined function name
• view name

host_variable_name

The name of the host variable into which the comment is to be placed.

The preceding COLON is optional; however, its use is strongly recommended.

Blanks before and after the colon are optional.

The rules for the name follow the client programming language conventions.

host_indicator_name

The name of the host indicator variable.

ANSI Compliance

COMMENT is a Teradata extension to the ANSI/ISO SQL:2011 standard.

Authorization

None.

COMMENT Returns Data

The returning form of COMMENT returns data.

Rules for the Returning Form of COMMENT

• The data type of host_variable_name must be VARCHAR(255).
• If no comment exists for the specific object, host_indicator_name returns NULL.
• Although the COMMENT statement returns only one data value (in effect, a single row containing a single column), you can use a selection cursor with a static COMMENT statement. Use the same procedure for the cursor as for a static selection cursor.
• If you execute a dynamic COMMENT statement, then you must use a dynamic cursor because data is returned. In this case, the same procedure is followed as with dynamic selection.
• If you use COMMENT with a cursor or as a dynamic SQL statement, then you must omit the INTO clause.