8.1 Transaction Handling

8.1.1 Processing Warnings

8.1.2 Error Handling

Transactions can be used to group operations into an atomic unit. Either all operations of a transaction succeed when they are committed, or none. It is possible to roll back a transaction as long as it has not been committed.

Transactions can be started in a session using the startTransaction() method, committed with commitTransaction() and cancelled or rolled back with rollbackTransaction(). This is illustrated in the following example. The example assumes that the test schema exists and that the collection my_collection does not exist.

from mysqlsh import mysqlx

# Connect to server
mySession = mysqlx.get_session( {
        'host': 'localhost', 'port': 33060,
        'user': 'user', 'password': 'password' } )

# Get the Schema test
myDb = mySession.get_schema('test')

# Create a new collection
myColl = myDb.create_collection('my_collection')

# Start a transaction
mySession.start_transaction()
try:
    myColl.add({'name': 'Rohit', 'age': 18, 'height': 1.76}).execute()
    myColl.add({'name': 'Misaki', 'age': 24, 'height': 1.65}).execute()
    myColl.add({'name': 'Leon', 'age': 39, 'height': 1.9}).execute()
    # Commit the transaction if everything went well
    mySession.commit()
    print('Data inserted successfully.')
except Exception as err:
    # Rollback the transaction in case of an error
    mySession.rollback()

    # Printing the error message
    print('Data could not be inserted: %s' % str(err))