Gridview rowupdating get old value alyssa shelasky dating
For example, when clicking the Edit button in an editable Grid View, the record's values are read from the database and displayed in Text Boxes and other Web controls. Later, after the user makes her changes and clicks the Update button, the original values plus the new values are sent to the Business Logic Layer, and then down to the Data Access Layer.
The Data Access Layer must issue a SQL statement that will only update the record if the original values that the user started editing are identical to the values still in the database. Figure 2: For the Update or Delete to Succeed, the Original Values Must Be Equal to the Current Database Values (Click to view full-size image) There are various approaches to implementing optimistic concurrency (see Peter A.
Ticket sales websites, which lock a particular seating location for short period while the user completes the order process, is an example of pessimistic concurrency control.
Optimistic concurrency control works by ensuring that the record being updated or deleted has the same values as it did when the updating or deleting process started.
Figure 3: Connect to the Same Northwind Database (Click to view full-size image) Next, we are prompted as to how to query the data: through an ad-hoc SQL statement, a new stored procedure, or an existing stored procedure.
Since we used ad-hoc SQL queries in our original DAL, use this option here as well.
This results in an to the corresponding Beverages category ID, and so on.Figure 4: Specify the Data to Retrieve Using an Ad-Hoc SQL Statement (Click to view full-size image) On the following screen, enter the SQL query to use to retrieve the product information. Discontinued = discontinued End Sub _ Public Function Update Product( By Val product Name As String, By Val supplier ID As Nullable(Of Integer), _ By Val category ID As Nullable(Of Integer), By Val quantity Per Unit As String, _ By Val unit Price As Nullable(Of Decimal), By Val units In Stock As Nullable(Of Short), _ By Val units On Order As Nullable(Of Short), By Val reorder Level As Nullable(Of Short), _ By Val discontinued As Boolean, By Val product ID As Integer, _ _ By Val original_product Name As String, _ By Val original_supplier ID As Nullable(Of Integer), _ By Val original_category ID As Nullable(Of Integer), _ By Val original_quantity Per Unit As String, _ By Val original_unit Price As Nullable(Of Decimal), _ By Val original_units In Stock As Nullable(Of Short), _ By Val original_units On Order As Nullable(Of Short), _ By Val original_reorder Level As Nullable(Of Short), _ By Val original_discontinued As Boolean, _ By Val original_product ID As Integer) _ As Boolean ' STEP 1: Read in the current database product information Dim products As _ Northwind Optimistic Concurrency.