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 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 custom logic for merging data easier.
Using the
BulkMergemethod is very simple. All you need to do is pass your entities as a parameter and let the automapping match properties with column names:
// @nuget: Z.Dapper.Plus
using Z.Dapper.Plus;
// 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:
// @nuget: Z.Dapper.Plus
using Z.Dapper.Plus;
// 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:
// @nuget: Z.Dapper.Plus
using Z.Dapper.Plus;
public void CustomBulkMerge<T>(List<T> entities, List<string> propertyIgnoreOnUpdateNames) where T : class
{
var context = new DapperPlusContext();
propertyIgnoreOnUpdateNames.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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