Example: INSERT and GENERATED ALWAYS Identity Columns - Analytics Database - Teradata Vantage

SQL Data Manipulation Language

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2024-04-05
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lifecycle
latest
Product Category
Teradata Vantage™

Assume that column_1 of newly created table_1 is an identity column defined as GENERATED ALWAYS. The following INSERT statements automatically generate numbers for column_1 of the inserted rows, even if they specify a value for that column.

     INSERT INTO table_1 (column_1, column_2, column_3)
     VALUES (111,111,111);
     INSERT INTO table_1 (column_1, column_2, column_2)
     VALUES (,222,222);

Check the inserts by selecting all the rows from table_1.

     SELECT *
     FROM table_1;

Result:

     *** Query completed. 2 rows found. 3 columns returned.
     *** Total elapsed time was 1 second.
      column_1  column_2  column_3
     --------- --------- ---------
             2       111       111
             1       222       222
Note the following things about this result:
  • Even though the value 111 was specified for column_1 in the first insert, the value is rejected and replaced by the generated value 2 because column_1 is defined as GENERATED ALWAYS.
  • A warning is returned to the requestor when a user-specified value is overridden by a system-generated number.
  • The first number in the identity column sequence is not necessarily allocated to the first row inserted because of parallelism.