Dataset updating database

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If you update a field in the Products table and post the change, then a SQL statements are generated, one for each table.

The order in which the statements are executed is important, because the new product might relate to the new supplier, so the new supplier is inserted first.

The Client Data Set/Provider architecture allows you to specify a primary update table (and advanced features actually not covered in the book) and also customize the updates' SQL, as we partially saw in Chapter 14 and we'll further explore in Chapter 16, "Multitier Data Snap Applications." ADO supports an equivalent to cached updates called batch updates, which are similar to the BDE approach.

Updating a data set synchronizes it with its external database.However, in this section you won't need them to solve the problem of updating a join, because in ADO, joins are naturally updatable.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).No error occurs, because the update has been applied successfully.

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