File organisation

Serial files are kept in
1. Time order.
2. Primary key order.
3. Size order.
4. An order determined by a secondary key.
Serial files are slow because
1. You have to start at the beginning of the file and work your way through all the data items until you get to the one you want.
2. They are stored on slow storage media.
3. You have to do complex calculations to work out where exactly some data is.
A master file is
1. Regularly updated compared to a transaction file.
2. Rarely updated compared to a transaction file.
3. Updated as often as a transaction file.
A shop records details of each product sold in a serial file. Before it is used to update the master file, it would be a good idea to
1. Put the file in a sequential order.
2. Put the file in a time order.
3. Put the file in a random order.
4. Do nothing and just update the master file.
Magnetic tapes are
1. Direct access devices.
2. Serial access devices.
3. Devices suitable for use with hash files.
4. Devices suitable for index sequential files.
Index sequential data structures are good structures if you need to
1. Sometimes search serially and sometimes search directly for a piece of data.
2. Rarely need to search for a data item except for data recovery purposes.
3. Only ever to search for some data serially.
4. Only ever need to access data directly.
Hash files are also known as
1. Random files.
2. Serial files.
3. Sequential files.
4. Index sequential files.
Using large areas of memory to store a few items of data in a hash file is known as
1. Redundancy.
2. Indexless.
3. Serial spanning.
4. Normalisation.
A good hashing algorithm
1. Minimises clashes.
2. Maximises clashes.
3. Maximises data redundancy.
4. Uses the most complex algorithm possible.
A hashing algorithm is simply
1. A maths formula.
2. An ELH diagram.
3. A DFD.
4. A data dictionary.