Entity Framework only with stored procedures?

Again, as most of the entity property names handily match the parameter names, the mappings will be automatically selected by the wizard with the exception of the SalesOrderID parameter. You’ll need to map that to the OrderID property. There are no return values for the UpdateOrder function so this task is complete.

If you were to run the QueryAndUpdateAnOrder method again, you will find that the stored procedure is executed rather than SQL dynamically generated by EF. There are two checkbox columns—Use Original Value and Rows Affected Parameter — in the function mapping that you can use with Update functions. You can also use the Rows Affected Parameter checkbox with Delete functions.

These settings force EF to perform concurrency checking when updating or deleting with stored procedures. You can see how this works when mapping the UpdateCustomer stored procedure to the Customer entity. Notice that the Customer entity has a TimeStamp property which maps to a column in the database table that is a rowversion (also known as timestamp) data type.

Any time a row in the table is modified, the database automatically updates this field with a new unique binary number. You don’t need to use a rowversion value to do concurrency checking in Entity Framework. Value-based concurrency control, detects conflicts whenever some or all of the column values have changed.

You can select any of the entity properties to be used for this. Here you can see how the function mapping allows you to take advantage of that when mapping an update stored procedure. The stored procedure uses the timestamp value as part of the filter to identify the row.

If the row was modified in the database (by another user or process) since it was retrieved, then that timestamp value will have changed and the row will not be found for the update. Now let’s see how that affects the mapping. In Figure 7, the UpdateCustomer function is mapped to the Customer entity.

The Use Original Value checkbox for the TimeStamp parameter/property mapping is checked. That tells the Entity Framework that when constructing the parameter values for the procedure to use the original TimeStamp value rather than the current value. The original value should be the value which originally came from the database.

By sending the original TimeStamp, which is then used as part of the WHERE predicate, the command will be able to detect if the row was modified since it was retrieved by EF’s query.