# Homogeneous Replication

With the exception of the data types listed in the table below, when replicating from an Oracle source to an Oracle target, all of the source and target data types will be identical.

Information note

* As of Oracle 9.0, the LONG and LONG RAW data types are no longer supported by Oracle.
* Primary/Unique Index names are preserved during homogeneous replication.
* In homogeneous replication, the source data first passes through the Qlik Replicate data type and is therefore subject to any limitations of that type.
* For information on Replicate data types and their limitations (where relevant), see [Replicate data types](https://help.qlik.com/en-US/replicate/November2024/Content/Replicate/Main/Endpoints/att_rep_data_types.htm).
* For information on which Replicate data types the source data passes through when replicating from Oracle, see the Oracle to Qlik Replicate data types mapping table described earlier.

Non-identical data types in homogeneous replicationreplication

| Oracle Data Types | Qlik Replicate Data Types |
| --- | --- |
| VARCHAR2 | Length &gt; 4000 bytes:<br><br>CLOB |
| NVARCHAR2 | Length &gt; 4000 bytes:<br><br>NCLOB |
| RAW | Length &gt; 2000 bytes:<br><br>BLOB |
| LONG<br><br>The LONG data type is not supported in [Batch optimized apply](https://help.qlik.com/en-US/replicate/November2024/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_applychangtunestab.htm#BatchOptimizedApply) mode.<br><br>To use this data type with Qlik Replicate, you must enable the use of LOBs for a specific task. | **CLOB** |
| LONG RAW<br><br>The LONG RAW data type is not supported in [Batch optimized apply](https://help.qlik.com/en-US/replicate/November2024/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_applychangtunestab.htm#BatchOptimizedApply) mode.<br><br>To use this data type with Qlik Replicate, you must enable the use of LOBs for a specific task. | **BLOB** |