| ### Construct data conversion and bridge programs

Understand the bridge performance requirements. If the bridge is slated to be burned, these are less important than for interface bridges:

- batch window
- on-line response time
- CPU usage
- disk usage

Verify bridge parameters to ensure that they are still appropriate:

- Communication protocols must be compatible for on-line bridges
- Database recoverability must be compatible when you are bridging database types.

Change data definitions by:

- altering date declarations to the specified format (expansion, compression...)
- creating additional data as needed to hold switches and codes
- defining new file and/or database types
- making these available to those modifying the corresponding code.

#### Construct data conversion programs

Implement data conversion by (in order from most to least effort):

- writing a data conversion program from scratch
- customizing a model data conversion program
- generating a data conversion program
- using a utility program
- defining a different database view

This is one place where using a century window can be quite useful:

1. To expand your data
2. Create a mirror image of your production system
3. Read in the old; write out the new

      READ OLD-INPUT-FILE
      CALL CEEDAYS USING OLD-INPUT-FILE-DATE,
                         OLD-PIC-STRING,
                         LILIAN-RETURN,
                         FC

      CALL CEEDATE USING LILIAN-RETURN,
                         NEW-PIC-STRING,
                         NEW-OUTPUT-FILE-DATE,
                         FC

      WRITE NEW-OUTPUT-RECORD

You can do the same thing for IMS and DB2 data.

DFSORT can do the same thing.

Implement date scrubbing via:

- inference rules (example: if policy number > 8000000 then billing cycle = 063097)
- default values (example: if membership date is invalid, set it to Dec 31 of current year)
- table lookups (example: change i1Z20O to 112200, "oh" to zero, "el" to one, "zee" to two)
- error suspense (hold record for manual correction)

Compile and link conversion programs.

#### Construct new bridge programs

Create bridge programs that:

- satisfy performance requirements
- maintain sufficient data integrity (real-time vs. batch updates)
- perform appropriate record selection
- contain sufficient validation and controls

Tip: you may be able to choose an implementation alternative:

- Avoid the need for a bridge to do on-line file updates by playing transactions twice: once for legacy update and once for compliant update
- Avoid the need for a bridge to do batch file updates by passing transaction records through the bridge and letting an update program within the owning partition do the updates
- Pass data records through the bridge, but let a separate update program do updates

Remember: in addition to building bridges between partitions, you may have to build interfaces (internal bridge) within a partition if a mix of date approaches is used.

©1997 IBM Corporation