Use constraint-based loading when the session option Treat Source Rows As is set to Insert. You might get inconsistent data if you select a different Treat Source Rows As option and you configure the session for constraint-based loading.
When the mapping contains Update Strategy transformations and you need to load data to a primary key table first, split the mapping using one of the following options:
Load primary key table in one mapping and dependent tables in another mapping. Use constraint-based loading to load the primary table.
Perform inserts in one mapping and updates in another mapping.
Constraint-based loading does not affect the target load ordering of the mapping. Target load ordering defines the order the Integration Service reads the sources in each target load order group in the mapping. A target load order group is a collection of source qualifiers, transformations, and targets linked together in a mapping. Constraint-based loading establishes the order in which the Integration Service loads individual targets within a set of targets receiving data from a single source qualifier.