Data Processing LO: Understanding the need for data processing and the methods used. Learning Outcome: Explain the following terms- Transaction file, master file, update, merge, file generations, serial access, direct access & batch processing

What’s the difference in getting to the music which you want …? Direct Access You can go directly to the part of the information which you want. Serial Access You may not be in the correct place, and so you have to search through the medium to find what you want. For music CDs the data are music tracks. In computer technology the terms are data records and files.

Direct or Serial Access?

Data Processing Changing data can be done in two ways: Real time/interactive. E.g. Changing addresses on a DB as you get them Batch Processing. Keeping the changes and doing them all at one time. Ad: Changes are immediate and the data is always up to date Disad: Expensive equipment and need to employ people to do the updates. Ad: Cheaper equipment and personnel. Disad: Data goes out of date.

Batch Processing Batch Processing usually occurs when there is a lot of data to read in and change at one time, e.g. cheques from a bank, new addresses to add to a customer database … etc. The current information is held in a Master File, the changes are held in the Transaction File.

What did I just say … Alex? Batch Processing usually occurs when there is a lot of data to read in and change at one time, e.g. cheques from a bank, new addresses to add to a customer database … etc. The current information is held in a Master File, the changes are held in the Transaction File.

Batch Processing Illustration Master File Transaction File Eg. Current bank account balances or name and address DB Eg. Cheques to be processed, new addresses Update / Merge Program The old master becomes part of the ancestral backup system. New Master File

Go through that again, Tash… Master File Transaction File Eg. Current bank account balances or name and address DB Eg. Cheques to be processed, new addresses Update / Merge Program The old master becomes part of the ancestral backup system. New Master File

Ancestral backup system (revision) New Master File Older Master File Old Master File Son Father Grandfather Also known as File Generations

Q. Direct or Serial? A. This used to be done with Serial files (tapes) but now it is mainly done with direct access. Master File Transaction File Update / Merge Program New Master File