The Sequence
Generator transformation generates numeric values. You can use the Sequence
Generator to create unique primary key values, replace missing primary keys, or
cycle through a sequential range of numbers.
The Sequence
Generator transformation is a connected transformation. It contains two output
ports that you can connect to one or more transformations. The Informatica
Server generates a value each time a row enters a connected transformation,
even if that value is not used. When NEXTVAL is connected to the input port of
another transformation, the Informatica Server generates a sequence of numbers.
When CURRVAL is connected to the input port of another transformation, the
Informatica Server generates the NEXTVAL value plus one.
You can make a
Sequence Generator reusable, and use it in multiple mappings. You might reuse a
Sequence Generator when you perform multiple loads to a single target.
For example, if you
have a large input file that you separate into three sessions running in
parallel, you can use a Sequence Generator to generate primary key values. If
you use different Sequence Generators, the Informatica Server might
accidentally generate duplicate key values. Instead, you can use the same
reusable Sequence Generator for all three sessions to provide a unique value
for each target row.
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