What are the steps involved in using a transaction object in ADO.NET?
1.Open a database connection.
2.Create the transaction object using the database connection object’s BeginTransaction method.
3.Create command objects to track with this transaction, assigning the Transaction property of each command object to the name of the transaction object created in step 2.
4.Execute the commands. Because the purpose of transaction processing is to detect and correct errors before data is written to the database, this is usually done as part of an error-handling structure.
5.Commit the changes to the database or restore the database state, depending on the success of the commands.
Close the database connection.
What property of a transaction object determines how concurrent changes to a database are handled?
IsolationLevel property of the transaction object is used to determine how concurrent changes to a database are handled.
What are different isolation levels of a transaction object in ADO.NET?
ReadUncommitted:Does not lock the records being read. This means that an uncommitted change can be read and then rolled back by another client, resulting in a local copy of a record that is not consistent with what is stored in the database. This is called a dirty read because the data is inconsistent.
Chaos:Behaves the same way as ReadUncommitted, but checks the isolation level of other pending transactions during a write operation so that transactions with more restrictive isolation levels are not overwritten.
ReadCommitted:Locks the records being read and immediately frees the lock as soon as the records have been read. This prevents any changes from being read before they are committed, but it does not prevent records from being added, deleted, or changed by other clients during the transaction. This is the default isolation level.
RepeatableRead:Locks the records being read and keeps the lock until the transaction completes. This ensures that the data being read does not change during the transaction.
Serializable:Locks the entire data set being read and keeps the lock until the transaction completes. This ensures that the data and its order within the database do not change during the transaction.
What is the default isolation level in a transaction?
What is a Save Point in a transaction in ADO.NET?
SqlConnection object provide one transaction capability that is unavailable for OLE database connections: the ability to create save points within a transaction. Save points let you restore the database state to a specific position within the current transaction. To set a save point within a SQL transaction, use the Save method as shown below.
How do you restore a SQL transaction to a specific save point?
To restore a SQL transaction to a save point, specify the name of the save point in the Rollback method as shown below.