PDI的steps：（4：Add sequence）

种类：转换；

id：Sequence；

描述：从sequence中获取下一个值。

所属类：addsequence.AddSequenceMeta

用来在stream中增加一个sequence，这个sequence，可以来自数据库，也可以是kettle自己生成的。

Examples:

Start at = 1, increment by = 1, max value = 3

This will produce: 1, 2, 3, 1, 2, 3, 1, 2...

Start at = 0, increment by = -1, max value = -2

This will produce: 0, -1, -2, 0, -1, -2, 0...|

Options

The table below contains the options for the Add Sequence step:

Option	Description
Step name	Name of the step; this name has to be unique in a single transformation.
Name of value	Name of the new sequence value that is added to the stream
Use DB to generate the sequence	Enable if you want the sequence to be driven by a database sequence. Connection name: choose the name of the connection on which the database sequence resides Schema name: specify the table's schema name (optional) Sequence name: allows you to enter the name of the database sequence
Use a transformation counter to generate the sequence	Enable if you want the sequence to be generated by Kettle Use counter to calculate sequence: Enable if you want the sequence to be generated by Kettle Counter name (optional): if multiple steps in a transformation generate the same value name, this option allows you to specify the name of the counter to which you want to associate with. Counter name avoids forcing unique sequencing across multiple steps. Start at: give the start value of the sequence. Increment by: give the increment of the sequence. Maximum value: maximum value after which the sequence return to the start value (Start At).