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.

connection.commit()

• rollback()- Causes a transaction to be rolled back to the starting.

connection.rollback()

• close()- Closes the connection to the database permanently.

connection.close()

This is all about transaction control in python.