System-Derived and System-Generated Columns | VantageCloud Lake - System-Derived and System-Generated Columns - 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

System-Derived Columns

System-derived columns have values that Vantage derives dynamically. These values are for internal use, and can be critical for user applications.

The following system-derived column types are supported by Vantage:
  • ROWID columns
  • PARTITION and PARTITION#L n columns

ROWID, PARTITION, and PARTITION#L n columns are system-defined and their values are system-generated.

System-Generated Columns

There are system-generated columns for which the DBA specifies the column name and whether the column is for a table, and there are system-generated columns whose existence, name, and contents are system-controlled.

The following system-generated column types are supported by Vantage:
  • Identity columns

    User-defined, but Vantage defines their values. (For GENERATED ALWAYS AS IDENTITY columns, column values are system-generated. For GENERATED BY DEFAULT AS IDENTITY columns, inserted column values can be user-generated or system-generated.)

    Identity column is supported on both the Block File System and Object File System. However, you can only run queries related to an identity column table on the primary cluster.
  • Object Identifier columns

    Similarly, BLOB, CLOB, and XML columns are user-defined, but Vantage defines the OID values that point to them.

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