(Glue-2305) Data Replication with Additional Options

Owned by SNP
May 16, 2023
4 min read

There is a possibility to use 2 additional options for data replication:

  • Capturing of timestamp

  • Capturing of deleted entries (only with trigger delta)

Capturing of timestamp

Change time field

There is a possibility to capture timestamps in the SNP Glue™ table. For this, a Change time field is required in the SNP Glue™ table. This field can have a custom name but data element /DVD/GL_CHANGE_TIME is mandatory for the field to be recognized as a Change time field. This field can be added in GL11 and also automatically generated via SNP Glue™Object Generator.

Usability

Change time field is used to capture the time stamp of an extraction. In the case of the standard full load timestamp of extraction is captured. If a trigger is used and the load type is different from the full load, the timestamp is taken from the shadow table. In this case, the change time is the same as the time of a captured operation in the shadow table.

Capturing of deleted entries 

In addition to the standard SAP table data replication, the SAP Table Fetcher with trigger delta can be set up to transfer also deleted records. These records will have only key field values filled in the target SNP Glue™ Table. If you want to distinguish them further, a deletion flag field can be added to the SNP Glue™ table, which will have a value D filled for deleted records using the rule Delete flag in the Extraction Process transformation mapping. Note, that deleted records are transferred after standard inserted/updated records.

For some storages, there is an option to persistently remove the records with the deletion flag D. For more information refer to the section (Glue-2305) Data Replication with Delta Type Trigger.

Additional steps to standard SAP table to Storage extraction

  1. To add the deletion flag field, go to SNP Glue™ Table and add the GLDELFLAG field using the button Add deletion flag. You can also add your own field, but in that case, the rule in the Extraction process will not be assigned automatically.

  2. In the SAP Table Fetcher, check the Read deleted entries checkbox.

  3. In the Extraction Process, the rule Delete flag should be assigned automatically using the Suggest transformation mapping button, if the default deletion flag field was used in step 1. Otherwise, select the rule manually.

Merge using captured deleted entries

When using the deletion flag to capture entries that have been removed, some storages can utilize the merge functionality. Currently supported storages:

  • MS SQL

  • Snowflake

  • Azure SQL

  • Azure Synapse

The merge functionality fetches the data and decides if the entries should be deleted or inserted/updated based on the deletion flag of the row.

The content of the shadow table used for the trigger load with the merge operation

 

The merge logic removes entries from the storage marked as DELETE and inserts/updates entries marked as UPDATE or INSERT. Based on values in the TYPE column the target deletion flag field contains the value D or ““ (space) during the load. If the source table is DSO or some structure, where this delta logic is already handled, the user does not have to set up the Capturing of deleted entries.

1. Capture deleted entries

The merge functionality uses the deletion flag field name to decide which entries should be deleted or inserted/updated. The setup is described in the section above.

This step is required only if there is no deletion field in the source structure. For example, DSOs have RECORDMODE in their structure by default. In this case, there is not required to create an additional field, only set it as a Delete field in the extraction process and in the consumer settings.

2. Consumer setup

When doing the merge setup, the SNP Glue™ table should already contain a deletion field (using trigger delta or default SAP field).

Extraction Process - GLDELFLAG marked as Delete flag

 

The consumer needs to have information about the deletion field. This setting can be applied while editing the consumer in the /DVD/GL80 transaction. Additional information is available on the SNP Glue™ Table Consumer page.