Add sequence
The Add sequence step adds a sequence value to the PDI stream.
A sequence is an ever-changing integer value with a specific start value and increment value. You can either:
Use a database sequence to generate the next value.
Generate the value in PDI by using a transformation counter.
PDI-generated sequence values are unique when used in the same transformation and reset to the start value each time you run the transformation.
Step name
Step name: Specify the unique name of the step on the canvas. Step name is set to
Step sequenceby default.
General
Name of value: Specify the name of the new sequence value field to add to the stream. Name of value is set to
valuenameby default.
Options
Choose one method to generate the sequence.
Select Use DB to generate the sequence? to drive the sequence by using a database sequence.
Use DB to generate the sequence?
Select this option to drive the sequence by using a database sequence. If you clear this option, Use counter to calculate sequence? is selected automatically.
Connection
Select the connection where your database sequence resides. If you do not have an existing connection, select New or Wizard. To modify an existing connection, select Edit.
Schema name (optional)
Specify the schema name of any related table. Select Schemas to choose a schema in the selected connection.
Sequence name
Specify the name of the database sequence. Select Sequences to choose a sequence in the selected connection.
Select Use counter to calculate sequence? to generate the sequence in PDI.
Use counter to calculate sequence?
Select this option to generate the sequence in PDI. This option is selected by default. If you clear this option, Use DB to generate the sequence? is selected automatically.
Counter name (optional)
Specify the counter name to avoid unique sequencing across multiple steps when multiple steps in a transformation generate the same value name.
Start at value
The start value for the sequence. For example, if Start at value is 1, the sequence starts with 1.
Increment by
The amount by which the sequence increases or decreases.
Maximum value
The value to reach before returning the sequence to the Start at value setting.
Example
If you set Start at value to 1, Increment by to 1, and Maximum value to 3, the resulting sequence is:
1, 2, 3, 1, 2, 3, 1, 2...
If you set Start at value to 0, Increment by to -1, and Maximum value to -2, the resulting sequence is:
0, -1, -2, 0, -1, -2, 0...
See also
Add value fields changing sequence (Pentaho Wiki). Adds a sequence when the values of a field change. Each time a value of at least one field changes, the added sequence resets to its start value.
Group By. Builds aggregates by grouping and generates sequential numbers within rows with repeating values.
Get ID from Slave Server (Pentaho Wiki). Use this step if you need a unique ID in a clustered environment.
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