COMMENT Usage Notes (Comment-Placing Form) - Teradata Vantage

Teradata® VantageCloud Lake
Deployment
VantageCloud
Edition
Lake
Product
Teradata Vantage
Published
January 2023
ft:locale
en-US
ft:lastEdition
2024-12-11
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phg1621910019905

Maps and Comments

You can specify an existing contiguous or sparse map, including TD_DataDictionaryMap or TD_GlobalMap.

Typical Use for COMMENT

The COMMENT (Comment-Retrieving Form) statement is typically used with a CREATE statement such as CREATE TABLE, CREATE METHOD, or CREATE TYPE to describe the:
  • Newly created database object.

You cannot place comments on indexes, so you cannot use this statement to place comment strings on join or secondary indexes.

Rules for Using COMMENT

  • Transaction Processing
    • The comment-placing form of COMMENT is processed as a DDL statement for transaction processing, and cannot be used in 2PC session mode.
    • A COMMENT request within an explicit transaction in Teradata session mode must be the last request in that transaction.
  • Comments on UDFs
    • COMMENT ON FUNCTION includes for simple external UDFs, table UDFs, and SQL UDFs.:

Japanese Characters in Comments

On Japanese language sites, comments can contain single byte characters, multibyte characters, or both from the KanjiShift-JIS character set.

For example, this comment contains single byte and multibyte characters.
THIS COMMENT IS USED FOR TABLE TAB  ""