|Oracle® Objects for OLE Developer's Guide
11g Release 2 (11.2) for Microsoft Windows
|PDF · Mobi · ePub|
After this method has been called, no database transactions are committed until a
CommitTrans is issued. Alternatively, the session can be rolled back using the
Rollback method. If a transaction has already been started, repeated use of the
BeginTrans method causes an error.
Delete methods fail on a given row in a dynaset in a global transaction after you issue a
BeginTrans, be aware that locks remain on those rows on which you called the
Delete method. These locks persist until you call a
OraDatabaseobject has been enlisted with Microsoft Transaction Server (MTS) and is part of a global MTS transaction, this method has no effect.
This example demonstrates the use of the
BeginTrans method to group a set of dynaset edits into a single transaction and uses the
Rollback method to cancel those changes. Copy this code into the definition section of a form. Then, press F5.
Sub Form_Load () 'Declare variables Dim OraSession As OraSession Dim OraDatabase As OraDatabase Dim OraDynaset As OraDynaset Dim fld As OraField 'Create the OraSession Object. Set OraSession = CreateObject("OracleInProcServer.XOraSession") 'Create the OraDatabase Object by opening a connection to Oracle. Set OraDatabase = OraSession. OpenDatabase("ExampleDb", _ "scott/tiger", 0&) 'Create the OraDynaset Object. Set OraDynaset = OraDatabase.CreateDynaset("select * from emp", 0&) 'Start Transaction processing. OraSession.BeginTrans 'Setup a field object to save object references. Set fld = OraDynaset.Fields("sal") 'Traverse until EOF is reached, setting each employees salary to zero Do Until OraDynaset.EOF = True OraDynaset.Edit fld.value = 0 OraDynaset.Update OraDynaset.MoveNext Loop MsgBox "All salaries set to ZERO." 'Currently, the changes have NOT been committed to the database. 'End Transaction processing. Using RollbackTrans 'means the rollback can be canceled in the Validate event. OraSession.Rollback 'MsgBox "Salary changes rolled back." End Sub