Extracting Large Volumes of Data Using an External Translation Table

Regular external translation table processing can take a long time and use a lot of memory if the translation table has a high volume of records. The @ONEROW feature can greatly reduce processing time.

Problem

In ACR/Detail, you need to extract transactions from daily reports that contain up to a million accounts in random order. Each transaction has a 16-digit account number, but this number is not the key. You want data for only those accounts that are present in the ACR/Detail history file. The number of accounts that reside in the file can be as many as 10,000 accounts.

Solution

Use the ACR/Detail history VSAM file as an external translation table and use the @ONEROW feature to speed processing. Follow the steps below to set up the history file as an external translation table with @ONEROW processing.

1 ) Under the Tables option, choose to set up an external translation table.

2 ) Enter @ONEROW for the description.

3 ) Choose VSAM Key Sequenced for the Dataset Organization.

4 ) Refer to the online help to enter the following information :

- File ID
- File Name
- Record Layout

5 ) For the Build Table Data Option, select On each lookup.

6 ) Follow the instructions in the online help or the ACR/Detail User Guide to specify the input and output parameters, define the table columns, specify the lookup rules, define the table build rules, and then create the job that will call the external translation table.

7 ) Select Reconcile to run the job.