Does this start two transactions?

General
1

Does this code start two transactions and only end one (PostgreSQL 9.1)?

app.myDbase.SQLExecute("Begin Transaction")

rs.Edit
rs.Field("field1").StringValue = "string1"
rs.Field("field2").StringValue = "string2"
rs.Update

If app.myDbase.Error Then
     MsgBox("DB Error: " + app.myDbase.ErrorMessage)
     app.myDbase.Rollback
Else
     app.myDbase.SQLExecute("End Transaction")
End If

I was wondering if “BEGIN TRANSACTION” starts one transaction and rs.Update then starts another transaction, then “END TRANSACTION” only ends one transaction and leaves the second transaction still open.

2

There is only one transaction:

[code]app.myDbase.SQLExecute(“Begin Transaction”)

rs.Edit
rs.Field(“field1”).StringValue = “string1”
rs.Field(“field2”).StringValue = “string2”
rs.Update

If app.myDbase.Error Then
MsgBox("DB Error: " + app.myDbase.ErrorMessage)
app.myDbase.Rollback
Else
app.myDbase.Commit // Commit will end the transaction
End If[/code]
Note that app.myDbase.SQLExecute(“Begin Transaction”) as rs.Edit will start a transaction automatically.

3

OK. I was reading that rs.Update starts a transaction (which is ended by app.myDbase.Commit), so I thought that app.myDbase.SQLExecute(“Begin Transaction”) followed by rs.Update might initiate a second (nested) transaction. I was then concerned that app.myDbase.SQLExecute(“End Transaction”) might only close one of the two transactions.

I looked up nested transactions in PostgreSQL and found out that it is not possible in PostgreSQL. Once a transaction is started, a second BEGIN TRANSACTION does nothing.

In PostgreSQL, app.myDbase.SQLExecute(“End Transaction”) and app.myDbase.Commit do the same thing.

4

Of course, you’re right.