A transaction system 's computer science (more precisely in the database theory ) is a subsystem that transactions on a database running. Transactions consist of several elementary operations which, from the (end) user's point of view, initially run invisibly in the background before they are combined into a visible unit. This is due to the fact that transaction processes leave their data stock in a correct state only after they have been completely (and error-free) processing (one speaks more precisely of a consistent state of the database).
Example for illustration
A bank manages accounts with the help of a database ( transaction system ). It handles many thousands of requests every day (withdrawals, deposits, account setups, account closures, lending; all of them transactions ). Each of these requests in turn consists of a fixed sequence of processing steps ( operations ):
Transaction "withdraw amount"
- Read the balance on the account.
- If the balance is greater than the amount to be withdrawn, then
- deduct the amount to be withdrawn from the balance,
- write the new credit into the balance and
- finish the transaction.
- cancel the transaction.
The task of the transaction system is to process as many transactions as possible as quickly as possible without errors occurring. The fastest way to do this is when transactions are carried out simultaneously ( concurrently ). However, problems with the database may arise ( inconsistencies ), e.g. B .:
Transaction 1: Add up the balance of accounts no. 1–10.
Transaction 2: Pay € 100 to account 7.
Although all parts of the instructions are important for account management, only those operations that influence the database are important for the transaction system - in this case:
- reading (read) from 1,
- the write from 4.,
- the end (commit) from 5. and
- the abort from 7.
Transaction system from the perspective of business administration
A transaction system is an IT system for processing business data . Unlike analysis systems , which perform a decision-oriented, higher-level planning function, it supports the inter-company data flows .
- ↑ transaction systems . Website of the University of Leipzig. Retrieved December 10, 2011.
- ↑ transaction system . Online encyclopedia of business informatics published by Oldenbourg Verlag. Retrieved December 10, 2011.
- ↑ transaction system . IT knowledge online lexicon. Retrieved December 10, 2011.