Teradata Parallel Data Pump

Chapter 3: Teradata TPump Commands
DML
Atomic Upsert Examples
This section describes several examples that demonstrate how the Atomic upsert feature
works, including cases where errors are detected and returned to the user. All of the examples
use the same table, called Sales, as shown below:
CREATE TABLE Sales, FALLBACK,
(ItemNbr INTEGER NOT NULL,
SaleDate DATE FORMAT 'MM/DD/YYYY' NOT NULL,
ItemCount INTEGER)
PRIMARY INDEX (ItemNbr);
It is assumed that the table has been populated with the following data:
INSERT INTO Sales (10, '05/30/2005', 1);
Assume that there exists a table called NewSales that has the same column definitions as those
of table Sales.
Example 1 (Error: Different Target Tables)
This example demonstrates an upsert statement that does not specify the same table name for
the UPDATE part and the INSERT part of the statement.
.Dml label upsertdml do insert for missing update rows;
UPDATE Sales SET ItemCount = ItemCount + 1 WHERE (ItemNbr = 10 AND
SaleDate = '05/30/2005');
INSERT INTO NewSales (10,'05/30/2005', 1);
A rule of an upsert statement is that only one single table is processed for the statement.
Because the tables, Sales and NewSales, are not the same for the upsert statement, an error is
returned, indicating that the name of the table must be the same for both the UPDATE and
the INSERT.
Example 2 (Error: Different Target Rows)
This example demonstrates an upsert statement that does not specify the same primary index
value for the UPDATE part and the INSERT part of the statement.
.Dml label upsertdml do insert for duplicate update rows;
UPDATE Sales SET ItemCount = ItemCount + 1 WHERE (ItemNbr = 10 AND
SaleDate = '05/30/2005');
INSERT INTO Sales (20,'05/30/2005', 1);
The primary index values for the UPDATE and the INSERT must be the same. Otherwise, we
would be looking at two different rows: one for UPDATE and the other for INSERT, which is
not the purpose of an upsert. An error is returned for the upsert statement because the
specified primary index values of 10 and 20 are not the same (the primary index value must be
the same for both the UPDATE and the INSERT).
Example 3 (Valid Upsert UPDATE)
This example demonstrates a successful upsert statement where a row gets updated.
.Dml label upsertdml do insert for missing update rows;
UPDATE Sales SET ItemCount = ItemCount + 1 WHERE (ItemNbr = 10 AND
SaleDate = '05/30/2005');
INSERT INTO Sales (10, '05/30/2005', 1);
Teradata Parallel Data Pump Reference 127