Data Migration

In addition to extracting sets of related data as part of the Compare Process when needed to obtain the source data, Compare enables you to extract the data as a separate, explicit process and store that data in an Extract File. When you extract the data as a separate process, you can compare data from different subsystems.

To specify the source you use an existing Access Definition or create a new Access Definition. The created Access Definition can be temporary, for a single use, or permanent, saved for repeated use. The Access Definition is used as input to the Extract Process. (See the Common Elements Manual, for a detailed discussion of creating and modifying Access Definitions.)

The Extract Process copies the specified data to an Extract File. The Extract File is saved and can be reused as needed.

To migrate data, select Option 7 MIGRATION on the Main Menu. (If Move is not installed, this option is SNAPSHOT.) The following panel is displayed when Move and Archive are also installed. (When only Compare is installed, the options to EXTRACT and BROWSE are available.)

------------------------------- Data Migration --------------------------------
OPTION ===>
                                                                 SQLID  ===> FOPDEMO
                                                                 SUBSYS ===> TDB2
1 EXTRACT - Extract Data from Source Tables                      LOCATION ===>
2 INSERT  - Insert Data into Destination Tables
3 LOAD    - Create Load Files and Perform Load
4 CREATE  - Create Tables and Related Object Definitions
5 CONVERT - Convert Extract File using Table and Column Maps
6 LIST    - List Extract Files in Directory
7 IMPORT  - Import Extract File and Populate Directory

R RETRY/RESTART  - Retry/Restart an Insert Process
B BROWSE         - Browse Content of Extract File or Control File

The following options are available on the Data Migration menu:

1 - EXTRACT

Specify the set of data to be extracted. After the set of source data is specified, this option extracts the data and stores it in an Extract File. (If Move is installed, the extracted data can include the rows from the tables and the object definitions for those tables. If Move is not installed, only the data is extracted.)

The specifications for the extracted data can be defined in an Access Definition and stored for repeated use or defined as temporary for one-time use.

If an unload program is available, it can be used to extract the data from Image Copy files or directly from the DB2^® VSAM files.

2 - INSERT: This option is only available when Move is installed. For detail, see the Move User Manual.

3 - LOAD: This option is only available when Move is installed. For detail, see the Move User Manual.

4 - DELETE: This option is only available when Archive is installed. For detail, see the Archive User Manual.

5 - CREATE: This option is only available when Move or Archive is installed. For detail, see the Move User Manual or the Archive User Manual.

6 - CONVERT: This option is only available when Move or Archive is installed. For details, see the Common Elements Manual.

7 - LIST: Display a list of Extract files that match selection criteria you specify. The List process allows you to manage extract files registered in the Optim Directory. With List you can display, delete, browse, generate a report or see extended information for an extract file. You can also select a file to use in an Insert process. This option is only available when Move is installed. Refer to the Move User Manual.
8 - IMPORT: Create entries to register extract files in the current Optim directory. An extract file stored on tape must be registered in the Optim Directory before it can be used in a Convert, Create, Insert, or Report process. This option is only available when Move is installed. Refer to the Move User Manual.

R RETRY / RESTART: This option is only available when Move or Archive is installed. For details, see the Common Elements Manual.

B BROWSE: Display an Extract File or Archive File to view the contents of that file or a Control File to examine extracted data or identify rows in error.

Data Migration menu prompts

The following prompts are available on Data Migration menu:

SQLID: The current SQLID. Modify this value to connect using a different SQLID.

SUBSYS: The current DB2 subsystem. Modify this value to connect to a different DB2 subsystem. When connecting to a remote subsystem, this value should be the local subsystem where the remote location is defined.

LOCATION: The remote location. This prompt is displayed if remote access is available. Specify a value to connect to a remote DB2 subsystem. You can use a percent sign (%) to obtain a selection list of available locations. If the connection fails, the session is restarted and the Main Menu is redisplayed. If you leave this prompt blank, the local subsystem is assumed.

Extracting Data

The Extract Process is used to create an Extract File. An Extract File contains the selected set of related rows from one or more tables. An Extract File on disk can be used as one or both sources for a Compare Process. The Extract File can be used repeatedly and simultaneously by many users.

Note: An extract file on tape cannot be used in a compare process.

An Extract File is created by traversing a set of tables and extracting specific data from those tables. The tables and the relationships to use to traverse those tables are specified in an Access Definition. You can use specifications from an existing Access Definition, create a new Access Definition, or specify temporary definitions.

The Access Definition also includes other specifications, such as:

Manual selection of specific rows in the Start Table. This selection process is referred to as Point-and-Shoot.
Selection criteria for one or more tables.
A maximum number of rows to extract for one or more tables.
A numeric value used to determine random selection, such as select every twentieth row.