The idea is that you have wrapper methods for CRUD (and all other data access) in the business layer so you'd write code like this: True this doesn't look much different than using the LINQ objects directly but the big difference is that you get some level of abstraction for the load and update code so you can inject things like tracing and error handling etc.
This is true even if no value is entered for those fields.If the data-bound control autogenerates fields for all fields in the data source, no values from the This example includes a text box that accepts user input, which is a potential security threat. NET Web pages validate that user input does not include script or HTML elements.That's fine if you use LINQ directly in your UI code but it's not all that great if you use LINQ in the middle tier.Incidentally Rob Connery also mentioned this in his LINQ Sonic Cast last week.The following sections answer some common issues that you might encounter when you implement LINQ. For more information, see Learning by Walkthroughs. I made a change to data in the database, but when I reran my application, the change was no longer there. Make sure that you call Submit Changes to save results to the database. In common scenarios where each object is processed only one time, the streaming model is superior in both Q.
Additional issues are addressed in Troubleshooting. Can I update table data without first querying the database? Although LINQ to SQL does not have set-based update commands, you can use either of the following techniques to update without first querying: Q.
Please use the database structure given below, if you want to try the following examples directly.
I am assuming, you already know how to create dbml/linq to sql classes: Being Lin Q as a ORM, it’s quite easy and sql syntax free way to insert data using Lin Q.
It does not support Xml Serializer or Binary Formatter. This approach eliminates the name/namespace collision. I get an error when I drag tables out of a SQL Server Compact 3.5 database. The Object Relational Designer does not support SQL Server Compact 3.5, although the LINQ to SQL runtime does. You must provide information such as the discriminator column, base class discriminator value, and derived class discriminator value.
Code generation in LINQ to SQL supports Data Contract Serializer serialization. When I have multiple DBML files that share some tables in common, I get a compiler error. Set the Context Namespace and Entity Namespace properties from the Object Relational Designer to a distinct value for each DBML file. In other cases, you should manually set Is Db Generated= Q.
Examples include the following: - An object not queried through the current Data Context (such as a newly created object).- An object created through deserialization- An object queried through a different Data Context.