Entity Framework Plus Batch Delete

Description

Deleting using Entity Framework can be very slow if you need to delete hundreds or thousands of entities. Entities are first loaded in the context before being deleted which is very bad for the performance and then, they are deleted one by one which makes the delete operation even worse.

EF+ Batch Delete deletes multiple rows in a single database roundtrip and without loading entities in the context.

// using Z.EntityFramework.Plus; // Don't forget to include this.

// DELETE all users inactive for 2 years
var date = DateTime.Now.AddYears(-2);
ctx.Users.Where(x => x.LastLoginDate < date)
         .Delete();

// DELETE using a BatchSize
var date = DateTime.Now.AddYears(-2);
ctx.Users.Where(x => x.LastLoginDate < date)
         .Delete(x => x.BatchSize = 1000);

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Scenarios

• Query Criteria
• Batch Size
• Batch Delay Interval
• Executing Interceptor

Query Criteria

The Delete IQueryable extension methods deletes rows matching the query criteria without loading entities in the context.

// using Z.EntityFramework.Plus; // Don't forget to include this.

// DELETE all users
ctx.Users.Delete();

// DELETE all users inactive for 2 years
var date = DateTime.Now.AddYears(-2);
ctx.Users.Where(x => x.LastLoginDate < date)
         .Delete();

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Try it (Async version)

Batch Size

The BatchSize property sets the amount of rows to delete in a single batch.

Default Value = 4000

// using Z.EntityFramework.Plus; // Don't forget to include this.
var date = DateTime.Now.AddYears(-2);
ctx.Users.Where(x => x.LastLoginDate < date)
         .Delete(x => x.BatchSize = 1000);

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Batch Delay Interval

The BatchDelayInterval property sets the amount of time (in milliseconds) to wait before starting the next delete batch.

Default Value = 0

// using Z.EntityFramework.Plus; // Don't forget to include this.

// Pause 2 seconds between every batch
var date = DateTime.Now.AddYears(-2);
ctx.Users.Where(x => x.LastLoginDate < date)
         .Delete(x => x.BatchDelayInterval = 2000);

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Executing Interceptor

The Executing property intercepts the DbCommand with an action before being executed.

// using Z.EntityFramework.Plus; // Don't forget to include this.

string commandText
var date = DateTime.Now.AddYears(-2);
ctx.Users.Where(x => x.LastLoginDate < date)
         .Delete(x => { x.Executing = command => commandText = command.CommandText; });

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Limitations

• DO NOT support Complex Type
• DO NOT support TPC
• DO NOT support TPH
• DO NOT support TPT

If you need to use one of this feature, you need to use the library Entity Framework Extensions

Conclusion

EF+ Batch Delete is the most efficient way to delete records. You drastically improve your application performance by removing the need to retrieve and load entities in your context and by performing a single database roundtrip instead of one for every record.

Need help getting started? info@zzzprojects.com

We welcome all comments, ideas and suggestions to improve our library.