Teradata Parallel Data Pump

Chapter 3: Teradata TPump Commands
DML
The Basic Upsert Feature
Example Upsert
When using the basic upsert feature:
• There must be exactly two DML statements in this DML group.
• The first DML statement must be an UPDATE statement that follows all of the Teradata
TPump task rules.
• The second DML statement must be an INSERT statement.
• Both DML statements must refer to the same table.
• The INSERT statement, when built, must reflect the same primary index specified in the
WHERE clause of the UPDATE statement. This is true for both a single column primary
index and a compound primary index.
By following these rules, a number of uses for the DO INSERT ROWS option can be found. In
the past, data could be presorted into INSERTs and UPDATEs, or UPDATEs attempted with
all the data, and then do an INSERT on any UPDATEs that failed. With upsert, Teradata
TPump needs only one pass of the data to UPDATE rows that need to be updated and INSERT
rows that need to be inserted.
Note: To ensure data integrity, the SERIALIZE parameter defaults to ON in the absence of an
explicit value if there are upserts in the Teradata TPump job.
When MARK MISSING UPDATE ROWS specified, while using DO INSERT ROWS, Teradata
TPump records any UPDATE that fails. This record appears in the Application Error Table,
together with an error code that shows that the INSERT of the DO INSERT ROWS was then
executed. If the INSERT fails, the INSERT row is also recorded in the Application Error table.
The default for an upsert function, however, is not to mark missing update rows. This is
because when the upsert function is performed, the INSERT is expected to occur when the
UPDATE fails. The failure of the UPDATE portion of an upsert does not, in itself, constitute
an error and should not be treated as one.
The MARK MISSING DELETE ROW option has no meaning when used with the DO
INSERT ROWS option.
The option of MARK (IGNORE) EXTRA DELETE (UPDATE) ROWS provides Teradata
TPump with a way to protect against an update or delete affecting multiple rows, which can
happen in Teradata TPump because the primary index can be non-unique.
MARK is the default for all DML options, except for an upsert.
Each record in the following example contains the value of the primary index column
(EmpNo) of a row of the Employee table whose PhoneNo column is to be assigned a new
phone number from field Fone.
When the UPDATE fails, the INSERT statement is activated and Teradata TPump enters the
upsert mode. In this case, each record contains the primary index value (EmpNum) of a row
that is to be inserted successively into the Employee table whose columns are EmpNo and
PhoneNo.
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