| What does commitment ordering attempt to do | Attempt to minimise issues from occurring with the database |
| How does Serialisation stop concurrent access | requests from other users are placed in a queue. Once the first user has finished using the field, the next command in the queue is executed and so on |
| What does commitment ordering take into account | The impact of commands on other parts of the database |
| How does Timestamp ordering stop concurrent access | Each commands assigned a timestamp
Commands are carried out on the field in the order of their timestamps. |
| How do record locks stop concurrent access | When a record is accessed by one user, it is immediately locked to other users until the
first user has finished using it. Other users are blocked from accessing or modifying the
content of a field until it has been unlocked |
| State wen the concurrent access issue occurs | When different users attempt to access the same field at the same time |
| How can the concurrent access issue be managed | use of record locks, serialisation, timestamp ordering, commitment ordering |
| How does commitment ordering stop concurrent access | An algorithm is used to work out an optimum order in which to execute commands for the same field |
| What can concurrent access issue result in? | can result in database updates being lost |
| Describe what the 'concurrent access issue' is with relation to client server databases | When different users attempt to access the same field at the same time |
| What does a client server database provide access to? | Database |
| Who does a client server database provide access to | Multiple clients |
| What do commands act on | Fields in databases |
