Bulk Update

Definition

UPDATE all entities in the database.

All rows that match the entity key are considered as existing and are UPDATED in the database.

Example

// Easy to use
context.BulkUpdate(list);

// Easy to customize
context.BulkUpdate(customers, options => options.ColumnPrimaryKeyExpression = customer => customer.Code);

Purpose

Updating entities using a custom key from file importation is a typical scenario.

Despite the ChangeTracker being outstanding to track what’s modified, it lacks in term of scalability and flexibility.

SaveChanges require one database round-trip for every entity to update. So if you need to update 10000 entities, then 10000 database round-trip will be performed which is INSANELY slow.

BulkUpdate in counterpart offer great customization and require the minimum database round-trip as possible.

Performance Comparisons

Operations 1,000 Entities 2,000 Entities 5,000 Entities
SaveChanges 1,000 ms 2,000 ms 5,000 ms
BulkUpdate 50 ms 55 ms 65 ms

FAQ

How can I specify more than one option?

You can specify more than one option using anonymous block.

Example

context.BulkUpdate(list, options => {
	options.BatchSize = 100);
	options.ColumnInputExpression = c => new {c.ID, c.Name, c.Description});
});

How can I specify the Batch Size?

You can specify a custom batch size using the BatchSize option.

Read more: BatchSize

Example

context.BulkUpdate(list, options => options.BatchSize = 100);

How can I specify custom columns to Update?

You can specify custom columns using the ColumnInputExpression option.

Read more: ColumnInputExpression

Example

context.BulkUpdate(list, options => options.ColumnInputExpression = c => new {c.Name, c.Description});

How can I specify custom keys to use?

You can specify custom key using the ColumnPrimaryKeyExpression option.

Read more: ColumnPrimaryKeyExpression

Example

// Single Key
context.BulkUpdate(customers, options => options.ColumnPrimaryKeyExpression = customer => customer.Code);

// Surrogate Key
context.BulkUpdate(customers, options => options.ColumnPrimaryKeyExpression = customer => new { customer.Code1, customer.Code2 });

How can I include child entities (Entity Graph)?

You can include child entities using the IncludeGraph option. Make sure to read about the IncludeGraph since this option is not as trivial as others.

Read more: IncludeGraph

Example

context.BulkUpdate(list, options => options.IncludeGraph = true);

Why BulkUpdate doesn’t use the ChangeTracker?

To provide the best performance as possible!

Since using the ChangeTracker can greatly reduce performance, we choose to let BulkSaveChanges method to handle scenario with ChangeTracker and BulkUpdate scenario without it.

Why BulkUpdate is faster than BulkSaveChanges?

The major difference between both methods is BulkSaveChanges use the ChangeTracker but not the BulkUpdate method.

By skipping the ChangeTracker, some methods like DetectChanges are no longer required which greatly helps to improve the performance.