Call StartTransaction to begin a new transaction against the database server. Before calling StartTransaction, an application should check the status of the InTransaction property and adjust the setting of the TransIsolation property as desired. If InTransaction is true, indicating that a transaction is already in progress, a subsequent call to StartTransaction without first calling Commit or Rollback to end the current transaction raises an exception. 

Updates, insertions, and deletions that take place after a call to StartTransaction are held by the server until an application calls Commit to save the changes or Rollback is to cancel them. 

InTransaction 

Commit 

Rollback 

TransIsolation