INFO: Ideas to Consider When Using Transactions Visual Basic

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List of ideas to keep in mind with Transaction Processing

• Keep the transaction processing loops as short as possible. For example:

       BeginTrans
        Statement1....
        Statement2....
        Statement3....
        Statement4.... '*** If you have a number of statements, you could
                       '*** slow processing in a multi-user system, or
                       '*** increase the chance of an error occurring.
  
       CommitTrans  (or Rollback)
   
  						

• When you are working with transaction statements, it is not recommended to proceed onto another form or load another form in the transaction processing loop. For example:

        BeginTrans
           Statement1....
           form2.Show  or form2.Show 1 or Load form2  '* Not recommended.
           Statement3....
           Statement4....
        CommitTrans  (or  Rollback)
  
  						

• When you are working with Data controls, it is not recommended to proceed onto another form in the transaction processing loop. For example:

        BeginTrans
           Statement1....
           form2.Show or Load form2    '*** Not recommended, may cause error
                                       '*** 3034 'Commit or Rollback without
                                       '*** BeginTrans' to occur.
           Statement3....
           Statement4....
        CommitTrans  (or  Rollback)
  
  						

• When you are working with data controls, it is not recommended to perform a Refresh method in the transaction processing loop. For example:

        BeginTrans
           Statement1....
           Data1.Refresh         '*** Not recommended, may cause error 3034
                                 '*** 'Commit or Rollback without BeginTrans'
           Statement3....        '*** to occur.
           Statement4....
        CommitTrans  (or  Rollback)
  
  						

• When you are working with Object variables, it is not recommended to perform a Dim of an Object variable in the transaction processing loop. For example:

        BeginTrans
           Dim db As Database                   '*** Not recommended.
           Dim ds As Dynaset                    '*** Not recommended.
           Dim tb As Table                      '*** Not recommended.
           Dim sn As Snapshot                   '*** Not recommended.
           Dim qy As Querydef                   '*** Not recommended.
           Statement1....
           Statement2....
        CommitTrans  (or  Rollback)
  
  						

• When you are working with Object variables, it is not recommended to perform a Open or Close method or function in the transaction processing loop. For example:

        BeginTrans
           Statement1....
           Set db = Opendatabase("Biblio.MDB")   '*** Not recommended.
           Set ds = Opentable("Authors")         '*** Not recommended.
           ds.Close                              '*** Not recommended.
           db.Close                              '*** Not recommended.
           Statement6....
           Statement7....
        CommitTrans  (or  Rollback)
  
  						

• When you are working with Object variables, it is not recommended to perform a Create... method or function in the transaction processing loop. For example:

        BeginTrans
           Statement1....   '*** The next line of code is not recommended.
           Set db = CreateDatabase("Mydb.MDB", DB_LANG_GENERAL, False)
           Set ds = db.CreateDynaset("Titles")      '*** Not recommended.
           Set sn = db.CreateSnapshot("Publishers") '*** Not recommended.
           Set qy = db.CreateQueryDef("Query1", "Select * From Authors;")
                       '*** The previous line of code is not recommended.
           Statement6....
           Statement7....
        CommitTrans  (or  Rollback)