If set to 0 (READ_UNCOMMITTED), other processes can be read from the database. Only modified data is locked and is not released until the transaction ends.
If set to 1 (READ_COMMITTED) other processes can change a row that your application has read if the cursor is not on the row you want to change. This level prevents other processes from changing records that your application has changed until your application commits them or ends the transaction.
If set to 2 (REPEATABLE_READ), other processes are prevented from accessing data that your application has read or modified. All read or modified data is locked until transaction ends.
If set to 3 (SERIALIZABLE), other processes are prevented from changing records that are read or changed by your application (including phantom records) until your program commits them or ends the transaction. This level prevents the application from reading modified records that have not been committed by another process. If your application opens the same query during a single unit of work under this isolation level, the results table will be identical to the previous table; however, it can contain updates made by your application.
Refer to "Locking and Isolation Levels" in the DataDirect Connect Series for ODBC Reference for details about ODBC isolation levels.
