1. Parameters and Functions Reference Guide
  2. Oracle GoldenGate Parameters
  3. MAP for Extract

MAP for Extract

Valid For

Extract

Description

You can also use MAP in an Extract parameter file to change the name of the transactions that Oracle GoldenGate stores for the table.

For example, consider that you capture the table scott.emp. For the first use case, you capture it to apply all the changes to anther table called scott.emp with the same structure, but you also want to capture scott.emp with a different set of columns and replicate that to a table called scott.emp_old. To make this work, you'll need an Extract parameter file similar to this: 

TABLE scott.emp; 
MAP scott.emp, 
cols(emp_no, employee_name), 
target scott.emp_old;

In the Replicat, you can do the following: 

MAP *.*, target *.*;

And the changes from scott.emp would go into scott.emp, the trail data for scott.emp_old would go into scott.emp_old.

Use the MAP parameter for Extract when Extract is operating in classic capture mode and you need to use the ALTID component of this parameter to map an object ID to an object name. ALTID specifies the correct object ID if Extract is capturing from Oracle transaction logs that were generated by a database other than the one to which Extract is connected. This configuration is required when Extract is not permitted to connect directly to the production (source) database to capture production transactions.

When Extract cannot connect directly to a source database, it connects to a live standby or other facsimile database, but it reads transaction logs that are sent from the source database. By querying the catalog of the alternate database, Extract can get the metadata that it needs to expand the transaction data into valid SQL statements, but it cannot use the object ID from this query. The local object ID for a table is different from the object ID of that table in the source database (and, thus, in the transaction log). You must manually map each table name to the source object ID by using a MAP statement with ALTID.

To Use MAP with ALTID

  • Create one MAP statement with ALTID for each table that you want to capture. Wildcarded table names are not allowed for a MAP parameter that contains ALTID.

  • To specify other processing for the same table (or tables), such as data filtering or manipulation, you must also create a TABLE statement for each of those tables. Wildcarding can be used to specify multiple tables with one TABLE statement, if appropriate.

  • Use a regular Replicat MAP statement in the Replicat parameter file, as usual. MAP for Extract does not substitute for MAP for Replicat, which is required to map source tables to target tables.

  • DDL capture and replication is not supported when using ALTID.

Default

None

Syntax

MAP [container.]schema.table, ALTID object_ID [, object_ID]
[container.]schema.table

The fully qualified name of the source table.

object_ID

The object ID of the table as it exists in the production (source) database.

If a table is partitioned, you can list the object IDs of the partitions that you want to replicate, separating each with a comma.

Examples

Example 1   

This example maps a non-partitioned table or just one partition of a partitioned table.

MAP QASOURCE.T2, ALTID 75740;
Example 2   

This example maps partitions of a partitioned table.

MAP QASOURCE.T_P1, ALTID 75257,75258;