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File Operations

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  1. File Operations GCSE GCSE ICT

  2. Master Files • A Master file is the main file of data stored by a business. • The data is mainly permanent… • …but there may be some fields that need changing from time to time. The Master file will be sorted in order of a Key field GCSE ICT

  3. Master File Example • A shop selling clothes may have a master file like this…(only 5 records are displayed) Which fields may need updating regularly? The shop needs to order some more of which item? GCSE ICT

  4. Transaction File • When the shop sells or buys an item - that is called a transaction. • The day’s transactions are placed on a transaction file. • The transaction file has temporary data… • …that is used to update (make changes to) the master file. GCSE ICT

  5. Transaction File Example • The transaction file will have fewer fields than the master file…(only five records are displayed) Transaction Type is ‘P’ for Purchase or ‘S’ for Sale. GCSE ICT

  6. File Update • The transaction file is used to update the master file. • The values of some of the fields in some of the records will be changed. The transaction file will be sorted first into the same order as the master file. GCSE ICT

  7. Update Example 24 – 1 = 23 57 + 1 = 58 The first transaction record… What data will be affected in the master file?... GCSE ICT

  8. Update Example 18 – 2 = 16 64 + 2 = 66 The 2nd transaction record… What data will be affected in the master file?... GCSE ICT

  9. Update Example 16 +10= 26 The 3rd transaction record… What data will be affected in the master file?... GCSE ICT

  10. The Update finished… The items of data in RED have changed… Not all records will be necessarily altered. This new master file will then be used for tomorrow’s update…and so on…. GCSE ICT

  11. The System Flowchart GCSE ICT