Row cannot be located for updating some values may
This behavior is essential for briefcase applications (discussed later in the chapter) and web applications, where there is no permanent connection to the database and, therefore, no way to implement pessimistic locking.In contrast with pessimistic locking, optimistic locking has the additional considerable benefit that resources are consumed only momentarily; therefore, the average resource usage is much lower, making the database more scalable. Assume you have an ADOData Set connected to the Customer table of the .From their point of view, when users delete a row in the grid, I would wager that 99 percent of them intend to delete just the product—not both the product and the supplier.Fortunately, you can achieve this result using another dynamic property—in this case, the Unique Table dynamic property.For example, the Join Data example is built around an ADODataset component that uses the previous SQL join.If you run it, you can edit one of the fields and save the changes (by moving off the record).In an ADO join, each field object knows which underlying table it belongs to.
', mt Confirmation, [mb Yes, mb No], 0) = mr Yes); end; filters based on the status of the record. Optimistic locking assumes there is a low probability that users will attempt to update the same records at the same time and that a conflict is unlikely.In ADO 2.6, the error message is "Row cannot be located for updating.