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how-to-submit-changes-to-the-database.md

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Learn more about: How to: Submit Changes to the Database
How to: Submit Changes to the Database
03/30/2017
csharp
vb
c7cba174-9d40-491d-b32c-f2d73b7e9eab

How to: Submit Changes to the Database

Regardless of how many changes you make to your objects, changes are made only to in-memory replicas. You have made no changes to the actual data in the database. Your changes are not transmitted to the server until you explicitly call xref:System.Data.Linq.DataContext.SubmitChanges%2A on the xref:System.Data.Linq.DataContext.

When you make this call, the xref:System.Data.Linq.DataContext tries to translate your changes into equivalent SQL commands. You can use your own custom logic to override these actions, but the order of submission is orchestrated by a service of the xref:System.Data.Linq.DataContext known as the change processor. The sequence of events is as follows:

  1. When you call xref:System.Data.Linq.DataContext.SubmitChanges%2A, [!INCLUDEvbtecdlinq] examines the set of known objects to determine whether new instances have been attached to them. If they have, these new instances are added to the set of tracked objects.

  2. All objects that have pending changes are ordered into a sequence of objects based on the dependencies between them. Objects whose changes depend on other objects are sequenced after their dependencies.

  3. Immediately before any actual changes are transmitted, [!INCLUDEvbtecdlinq] starts a transaction to encapsulate the series of individual commands.

  4. The changes to the objects are translated one by one to SQL commands and sent to the server.

At this point, any errors detected by the database cause the submission process to stop, and an exception is raised. All changes to the database are rolled back as if no submissions ever occurred. The xref:System.Data.Linq.DataContext still has a full recording of all changes. You can therefore try to correct the problem and call xref:System.Data.Linq.DataContext.SubmitChanges%2A again, as in the code example that follows.

Example

When the transaction around the submission is completed successfully, the xref:System.Data.Linq.DataContext accepts the changes to the objects by ignoring the change-tracking information.

[!code-csharpDLinqSubmittingChanges#1] [!code-vbDLinqSubmittingChanges#1]

See also