Switch stage in DataStage example

Switch stage example

Use the Switch stage to implement a switch statement.

The following example shows how a Switch stage implements a switch statement:


switch (selector)
{
   case 0:          // if selector = 0,
            // write record to output data set 0
            break;
   case 10:          // if selector = 10,
            // write record to output data set 1
            break;
   case 12:             // if selector = discard value (12)
               // skip record
               break;
   case default:             // if selector is invalid,
               // send row down reject link
};

The metadata input to the switch stage listed in the following table.

Table 1. Column definitions
Column name	SQL type
Select	Integer
col1	Char
col2	Char
col3	Char

In this example, the Select column is the selector. Each input row is assigned to an output data set based on the value of the selector.

To implement the switch statement, the properties of the stage are set to the following values.

Table 2. Example Switch stage properties
Property	Value
Selector	Select
Selector Mode	User-defined Mapping
Case	0=0
Case	10=1
Case	12=5
Discard Value	5

In this example, any rows that have a 0 in the Select column are sent to output link 0. Any rows that have a 10 in the Select column are sent to output link 1, and any rows that have a 12 in the Select column are discarded.