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:documentationPath: /pipeline/transforms/
:language: en_US
:description: The Synchronize After Merge transform can be used in conjunction with the Merge Rows (Diff) pipeline transform to insert/update/delete database fields based on the Merge Rows (Diff) output.

= image:transforms/icons/synchronizeaftermerge.svg[Synchronize after merge transform Icon, role="image-doc-icon"] Synchronize after merge

[%noheader,cols="3a,1a", role="table-no-borders" ]
|===
|
== Description

The Synchronize After Merge transform can be used in conjunction with the Merge Rows (Diff) pipeline transform to insert/update/delete database fields based on the Merge Rows (Diff) output.

The Merge Rows (diff) pipeline transform appends a Flag column to each row, with a value of "identical", "changed", "new" or "deleted".

This flag column is then used by the Synchronize After Merge pipeline transform to carry out updates/inserts/deletes on a connection table.

|
== Supported Engines
[%noheader,cols="2,1a",frame=none, role="table-supported-engines"]
!===
!Hop Engine! image:check_mark.svg[Supported, 24]
!Spark! image:question_mark.svg[Maybe Supported, 24]
!Flink! image:question_mark.svg[Maybe Supported, 24]
!Dataflow! image:question_mark.svg[Maybe Supported, 24]
!===
|===

== Options

=== General Tab

[options="header"]
|===
|Option|Description
|Transform name|Name of the transform.
|Connection|The database connection to which data is written
|Target schema|The name of the Schema for the table to which data is written.
This is important for data sources that allow for table names with periods in them.
|Target table|Name of the table in which you want to do the insert/update/delete.
|Commit size|The number of rows to change before running a commit.
|Use batch update|
|Tablename is defined in a field|
|Key Lookup table|Allows you to specify a list of field values and comparators.
You can use the following comparators: =, <>, <, <=, >, >=, LIKE, BETWEEN, IS NULL, IS NOT NULL
|Update Fields|Allows you to specify all fields in the table you want to insert/update including the keys.
Avoid updates on certain fields (e.g. primary keys or non-null constrained fields) by specifying N in the update column.
|SQL button|Click SQL to generate the SQL to create the table and indexes for correct operation.
|===

=== Advanced Tab

[options="header"]
|===
|Option|Description|Default value from the Merge Rows (diff) transform
|Operation fieldname|This is a required field.
This field is used by the transform to obtain an operation flag for the current row.|"flagfield"
|Insert when value equal|Specify the value of the Operation fieldname which signifies that an Insert should be carried out.|"new"
|Update when value equal|Specify the value of the Operation fieldname which signifies that an Update should be carried out.|"changed"
|Delete when value equal|Specify the value of the Operation fieldname which signifies that a Delete should be carried out.|"deleted"
|Perform lookup|Performs a lookup when deleting or updating.
If the lookup field is not found, then an exception is thrown.
This option can be used as an extra check if you wish to check updates/deletes prior to their execution.|Not applicable
|===
