Sequence Generator Output Fields
The Sequence Generator transformation has two output fields, NEXTVAL and CURRVAL. You cannot edit or delete these fields. Additionally, you cannot add fields to the Sequence Generator transformation.
You do not need to map both of the output fields. If you do not map one of the output fields, the Mapping Configuration task ignores the unmapped field.
Use the NEXTVAL field to generate a sequence of numbers based on the Initial Value and Increment By properties.
Map the NEXTVAL field to an input field in a Target transformation or other downstream transformation to generate a sequence of numbers. If you do not configure the Sequence Generator to cycle through the sequence, the NEXTVAL field generates sequence numbers up to the configured End Value.
You can connect a Sequence Generator transformation to any transformation. However, it cannot be connected alone. At least one field from another transformation must be included in the mapping along with the Sequence Generator fields.
If you map the NEXTVAL field to multiple transformations, the Mapping Configuration task generates a unique sequence of numbers for each transformation. If you want the Sequence Generator to generate the same sequence of numbers for multiple transformations, you can place an Expression transformation between the Sequence Generator and the transformations to stage the sequence of numbers.
The CURRVAL field value is the NEXTVAL value plus the Increment By value. For example, if the Initial Value is 1 and Increment By is 1, the Mapping Configuration task generates the following values for NEXTVAL and CURRVAL:
Typically, you map the CURRVAL field when the NEXTVAL field is already mapped to a downstream transformation in the map. If you map the CURRVAL field without mapping the NEXTVAL field, the Mapping Configuration task generates the same number for each row.