The properties of each class map to the columns of a corresponding table in the database.Each instance of a class entity represents a row within the database table.Note that if a Product's property values weren't changed by the property assignments above, then the object would not be considered changed and LINQ to SQL would therefore not execute an update for that product back to the database.For example - if the "Chai" product's unitprice was already and the number of units in stock was 4, then calling Submit Changes() would not cause any database update statements to execute.Note the use of a generic index based scheme for reading data from the edit row and writing the new data to the appropriate row in the Data Set.Since the data in the Data Grid may not be synchronized with the data in the Data Set, you must find the proper row in the Data Set using the primary key of the selected row.
The Data Grid has built in support for an edit row and "Edit", "Update", and "Cancel" buttons.
For example, I could write the below code to update the price and # of units in stock of the "Chai" product in the database: When I call northwind.
Submit Changes() above, LINQ to SQL will dynamically construct and execute a SQL "UPDATE" statement that will update the two product property values we modified above.
LINQ to SQL will then automatically translate these LINQ query expressions to the appropriate SQL code to execute at runtime.
For example, I could write the below LINQ expression to retrieve a single Product object by searching on the Product name: I could then write the LINQ query expression below to retrieve all products from the database that haven't yet had an order placed for them, and which also cost more than 0: Note above how I am using the "Order Details" association for each product as part of the query to only retrieve those products that have not had any orders placed for them.