To give instructions to database we use SQL or Structured Query language.
The primary purpose is to query and manipulate data stored in a relational database. Statement of SQL is classified into 5 categories:-
- Data definition language
- Data retrieval
- Data manipulation language
- Transaction control
- Data control
The purpose of transaction control is managing changes made by DML (Data Manipulating language) statements.
- Atomicity- Either the transaction completes, or nothing happens. If a transaction contains 4 queries then all these queries must be executed, or none of them must be executed.
- Consistency- The database must be consistent before the transaction starts and the database must also be consistent after the transaction is completed.
- Isolation- Intermediate results of a transaction are not visible outside the current transaction.
- Durability- Once a transaction was committed, the effects are persistent, even after a system failure.
These properties are popularly known as ACID properties.
There are some functions also which helps in transaction control:-
- commit()- Exactly commits pending transactions to the database.
- rollback()- Causes a transaction to be rolled back to the starting.
- close()- Closes the connection to the database permanently.
This is all about transaction control in python.