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What is the most efficient way to implement update row if it exists, else insert new row logic using Entity Framework? Or are there any patterns for this?
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We can update records either in connected or disconnected scenarios. In the connected Scenario, we open the context, query for the entity, edit it, and call the SaveChanges method. In the Disconnected scenario, we already have the entity with use. Hence all we need to is to attach/add it to the context.
The steps to update an existing entity are quite simple. First retrieve an instance of the entity from the EntitySet<T> (in our case ObjectSet<Customer>), then edit the properties of the Entity and finally call SaveChanges() on the context.
In Entity Framework, the SaveChanges() method internally creates a transaction and wraps all INSERT, UPDATE and DELETE operations under it. Multiple SaveChanges() calls, create separate transactions, perform CRUD operations and then commit each transaction.
EntityState.Added : EntityState.Modified; context.SaveChanges(); } } Note that when you change the state to Modified all the properties of the entity will be marked as modified and all the property values will be sent to the database when SaveChanges is called.
If you are working with attached object (object loaded from the same instance of the context) you can simply use:
if (context.ObjectStateManager.GetObjectStateEntry(myEntity).State == EntityState.Detached) { context.MyEntities.AddObject(myEntity); } // Attached object tracks modifications automatically context.SaveChanges(); If you can use any knowledge about the object's key you can use something like this:
if (myEntity.Id != 0) { context.MyEntities.Attach(myEntity); context.ObjectStateManager.ChangeObjectState(myEntity, EntityState.Modified); } else { context.MyEntities.AddObject(myEntity); } context.SaveChanges(); If you can't decide existance of the object by its Id you must execute lookup query:
var id = myEntity.Id; if (context.MyEntities.Any(e => e.Id == id)) { context.MyEntities.Attach(myEntity); context.ObjectStateManager.ChangeObjectState(myEntity, EntityState.Modified); } else { context.MyEntities.AddObject(myEntity); } context.SaveChanges(); If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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