How to use transactions and locks

To change two columns of the current record, the sequence of calls would be coded:

BeginTransaction() //Gets a shared read-lock on the database
UpdateRecord()
WriteUintL() //Tries to upgrade to an exclusive write-lock
WriteTextL()
PutRecordChanges()
CommitTransaction() //Unlocks database

To read more than one record and guarantee that the content of each record does not change between the read operations, wrap the set of read operations within a transaction.

BeginTransaction() //Gets a shared read-lock on the database
ReadUintL()
GotoNextRecord()
ReadUintL()
CommitTransaction() //Unlocks database