A DMI message is organized hierarchically with one top-level parent segment and one or more second-level child segments. Second-level child segments may have one or more third-level child segments.

To maintain the structure of the DMI data, the SAP DMI Prepare transformation uses primary and foreign keys. The top-level parent segment has a primary key. Each child segment has a primary key and a foreign key. The foreign key of each child segment references the primary key of its parent segment. For example, the foreign key of a second-level child segment references the primary key of the top-level parent segment. Similarly, the foreign key of a third-level child segment references the primary key of the second-level child segment.

The SAP DMI Prepare transformation groups incoming data based on the values in the primary and foreign key fields. The Control Input group of the SAP DMI Prepare transformation represents the parent segment. All other groups of the SAP DMI Prepare transformation except the DMI_Prepare_Error_Output group represent second-level or third-level child segments.

The following table shows the groups of the SAP DMI Prepare transformation and the fields used for the primary and foreign keys:

Each value for the GPK_<name> field must be unique. Each GFK_<parent_name>_<group_name> field must reference the primary key of its parent segment.

The following example shows the relationship of primary and foreign keys in a DMI document named ABSEN1 with four child segments:

The SAP DMI Prepare transformation uses these primary and foreign key relationships to maintain the structure of the DMI data. Any foreign key field that does not match the primary key of its parent segment results in an orphan row. Any primary key field that is not unique results in a duplicate row.

Verify that each DMI document has a unique primary key for the top-level parent segment, each child segment, and that each foreign key matches the primary key of its parent.