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Using transactions with the BDE
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The BDE supports local transactions against Paradox, dBASE, Access, and FoxPro tables. From a coding perspective, there is no difference to you between a local transaction and a transaction against a remote database server.
Note: When using transactions with local Paradox, dBASE, Access, and FoxPro tables, set TransIsolation to tiDirtyRead instead of using the default value of tiReadCommitted. A BDE error is returned if TransIsolation is set to anything but tiDirtyRead for local tables.
When a transaction is started against a local table, updates performed against the table are logged. Each log record contains the old record buffer for... more 
With passthrough SQL, you use a TQuery, TStoredProc, or TUpdateSQL component to send an SQL transaction control statement directly to a remote database server. The BDE does not process the SQL statement. Using passthrough SQL enables you to take direct advantage of the transaction controls offered by your server, especially when those controls are non-standard.
To use passthrough SQL to control a transaction, you must
  • Install the proper SQL Links drivers. If you chose the "Typical" installation when installing Delphi, all SQL Links drivers are already properly installed.
  • Configure your network protocol. See your network administrator for more... more 
By default, the BDE provides implicit transaction control for your applications. When an application is under implicit transaction control, a separate transaction is used for each record in a dataset that is written to the underlying database. Implicit transactions guarantee both a minimum of record update conflicts and a consistent view of the database. On the other hand, because each row of data written to a database takes place in its own transaction, implicit transaction control can lead to excessive network traffic and slower application performance. Also, implicit transaction control will not protect logical operations that span more than one... more 
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