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SAP Sybase SQL Anywhere 16.0 » UltraLite - .NET Programming » UltraLite.NET application development


Transaction management

UltraLite provides transaction processing to ensure the integrity of the data in your database. A transaction is a logical unit of work. Either an entire transaction is executed, or none of the statements in the transaction are executed.

By default, UltraLite.NET operates in AutoCommit mode, so that each insert, update, or delete is executed as a separate transaction. Once the operation is complete, the change is made to the database.

To use multi-statement transactions, you must create a ULTransaction class object by calling ULConnection.BeginTransaction. For example, if your application transfers money between two accounts, both the deduction from the source account and the addition to the destination account must be completed as a distinct operation, otherwise both statements must not be completed.

If the connection has performed a valid transaction, you must execute ULTransaction.Commit statement to complete the transaction and commit the changes to your database. If the set of updates is to be abandoned, execute ULTransaction.Rollback statement to cancel and roll back all the operations of the transaction. Once a transaction has been committed or rolled back, the connection will revert to AutoCommit mode until a subsequent call to ULConnection.BeginTransaction.

For example, the following code fragment shows how to set up a transaction that involves multiple operations (avoiding the default autocommit behavior):

// Assuming an already open connection named  conn
ULTransaction txn = conn.BeginTransaction(IsolationLevel.ReadUncommitted);
// Perform transaction operations here

UltraLite supports only the ReadCommitted and ReadUncommitted members of the IsolationLevel enumeration.

Some SQL statements—especially statements that alter the structure of the database—cause any pending transactions to be committed. Examples of SQL statements that automatically commit transactions in progress are: CREATE TABLE and ALTER TABLE.

 See also