A merge is equivalent to an UPSERT (Update/Insert) operation. Existing data in the database will be updated, and non-existing data will be inserted.
The easiest and fastest way to merge data is by using the Dapper Plus third-party library.
The BulkMerge method makes that operation very easy to use and improves the performance by 5000% depending more on the provider (Online Benchmark).
Getting Started
NuGet Package: https://www.nuget.org/packages/Z.Dapper.Plus/
Documentation: Dapper Plus – Bulk Merge
Dapper BulkMerge
Dapper Plus BulkMerge helps with Bulk Merge operations for Dapper. It allows you to perform bulk inserts, updates, and deletes into the database in a single operation.
- It can reduce the complexity of writing multiple queries and adds an extra layer of performance optimization.
- It also supports batching, which helps minimize round trips to the database by grouping commands together.
- Additionally, it provides helpful features such as conditional merging, making creating custom logic for merging data easier.
Using the
BulkMergemethod is very simple. All you need to do is pass your entities in the parameter and let the automapping matching properties with column names:
// Easy to use
connection.BulkMerge(products);
// Easy to customize
connection.UseBulkOptions(options => options.MergeKeepIdentity = true)
.BulkMerge(products);
Dapper BulkMerge with Global Context Mapping
The BulkMerge is also very flexible. It is possible to insert all properties and ignore some properties during the updates phase:
// Global Mapping requires to be mapped globally only once
DapperPlusManager.Entity<Customer>("Customer_IgnoreAuditProperty")
.IgnoreOnMergeUpdate(x => new { x.CreatedDate, x.CreatedUser });
// ...code...
connection.BulkMerge("Customer_IgnoreAuditProperty", customers);
Dapper BulkMerge with Instance Context Mapping
When using a global context mapping, you need to set the mapping only once since it is global, but that’s also possible to set the mapping inside a method to specify some configuration at runtime:
public void CustomBulkMerge<T>(List<T> entities, List<string> propertieIgnoreOnUpdateNames) where T : class
{
var context = new DapperPlusContext();
propertieIgnoreOnUpdateNames.ForEach(x =>
{
context.Entity<T>().IgnoreOnMergeUpdate(x);
});
context.BulkMerge(entities);
}
All of these features make BulkMerge an essential method for optimizing the performance of your data access layer.
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