Transactions ensure the data consistency of the database. We have to make sure that more than one applications must not modify the records while performing the database operations. The transactions have the following properties.
Python provides the commit() method which ensures the changes made to
the database consistently take place.
The syntax to use the commit() method is given below.
conn.commit() #conn is the connection object
All the operations that modify the records of the database do not take place until the commit() is called.
The rollback() method is used to revert the changes that are done to the database. This method is useful in the sense that, if some error occurs during the database operations, we can rollback that transaction to maintain the database consistency.
The syntax to use the rollback() is given below.
We need to close the database connection once we have done all the operations regarding the database. Python provides the close() method. The syntax to use the close() method is given below.
In the following example, we are deleting all the employees who are working for the CS department.
import mysql.connector #Create the connection object myconn = mysql.connector.connect(host = "localhost", user = "root",passwd = "google",database = "PythonDB") #creating the cursor object cur = myconn.cursor() try: cur.execute("delete from Employee where Dept_id = 201") myconn.commit() print("Deleted !") except: print("Can't delete !") myconn.rollback() myconn.close()