This section explains the pattern for data linkage from n tables to one table.

You use a merge table to combine multiple source tables into one at the target for import into a single table. You can create a merge table at the target system, combine multiple source tables into one table, and then import it into a single table. Changes made by such commands as INSERT, DELETE, and PURGE TABLE are converted according to the merge table rules or the load statements specified in the import table definition.

The following figure shows an example of combining multiple source tables into one table at the target, and then importing that table into a single table using a merge table.

Figure 4-11 Example of combining multiple source tables into one at the target, and then importing it into a single table using a merge table

Explanation

• Extracting and sending multiple tables at the source
  To extract update information for multiple tables at the source, specify as many extraction statements as there are tables to be extracted.
  
• Importing multiple tables into a single table at the target
  To import multiple tables into a single table at the target, specify as many update information field definitions and import table definitions as there are tables to be extracted. In this case, specify user-defined dummy field names in the update information field definitions because correspondence must be established between the numbers of columns at the source and target tables. Use a const clause to specify each field name.
  

You must specify in the import table definitions all the field names that are specified in the update information field definitions. When you create a merge table, specify sqlconvopt1 or sqlconvopt2 in front of the table name in the to clause in the import table definition.