System Variables

System variables are the variables defined by Data Exchange to describe transformation information.

Using system variables you can, for example, perform a logical delete; that is, mark a target record as deleted when the source record is deleted physically. Before you perform a logical delete, the source DML command Delete, on the classifier level, must have the target DML command set to Update.

To perform a logical delete for the target feature, you will need to define an expression similar to the following:

IfElse(<<$Source_DML_Command>> == “Delete”,”X”, IfElse(<<$Source_DML_Command>> == “Update”,”U”,”I”))

The expression checks the source DML command and assigns a value to the target. If the source DML command is Delete, the target is assigned the value X. Similarly, if the source DML command is Update, the target is assigned the value U, otherwise it is assigned the value I, which represents Insert.

The following table lists the available system variables.

Table 2. System Variables

System Variable

Description

$Source_Classifier_NameThe source classifier name
$Source_Data_Manager_TypeThe type of the source data manager (Enterprise Database Server, RDMS, SQL Server)
$Source_DML_CommandThe DML command at the source
$Source_Feature_NameThe source feature name
$Source_HostThe host of source data manager
$Source_Schema_NameThe source schema name
$Source_UserThe user id which Runtime uses to connect to the source.
$Target_Classifier_FilterThe classifier filter string defined on the target classifier
$Target_Classifier_NameThe target classifier name
$Target_Data_Manager_TypeThe type of the target data manager (Enterprise Database Server, SQL Server, Oracle database, Kafka)
$Target_ DML_CommandThe DML command at the target
$Target_Feature_ExpressionThe expression string defined on the target feature
$Target_Feature_NameThe target feature name
$Target_HostThe host of target data manager
$Target_Schema_NameThe target schema name
$Target_UserThe user id which Runtime uses to connect to the target.
$Transformation_IdThe GUID of the transformation
$Transformation_NameThe name of the transformation
$Transformation_VersionThe deployed version of the transformation
$DE_Processing_Local_DateTimeThe local date time available on the Runtime processing partition
$DE_Processing_UTC_DateTimeThe UTC date time available on the Runtime processing partition