DB Extensions Bulk SQL for Dapper and ADO.NET

Like Dapper, we extend your IDbConnection. Keep querying with Dapper. Write thousands of rows with one extra method — much faster than a loop.

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DbExtensions adds BulkInsert, BulkUpdate, BulkDelete, and BulkMerge to the same connection Dapper already uses. One extra using. No new client. That is why it fits Dapper so well — and any other ADO.NET code.

Still writing this?

foreach (var customer in customers)
    connection.Execute(
        "INSERT INTO Customer (Id, Name, City) VALUES (@Id, @Name, @City)",
        customer);

One call instead — and much faster

connection.BulkInsert(customers);

The second snippet is not just shorter. On SQL Server, 5,000 inserts took 8 seconds with the loop and 70 ms with BulkInsert() — about 110× faster. Update, delete, and merge follow the same pattern.

Operation	Dapper, row by row	DbExtensions	Faster
Insert	7.9 s	0.07 s	110×
Update	7.7 s	0.42 s	18×
Delete	7.5 s	0.27 s	28×
Merge	11.6 s	0.28 s	41×

5,000 rows, local SQL Server. How we measured this.

Insert, update, delete, merge

Same connection as Dapper. One method each — not a new client.

using ETLBox.DbExtensions;

var connection = new SqlConnection("your-connection-string");
var customers = Enumerable.Range(1, 10_000)
    .Select(i => new Customer { Id = i, Name = $"Name {i}", City = $"City {i % 50}" });
connection.BulkInsert(customers);

public class Customer {
    public int Id { get; set; }
    public string Name { get; set; }
    public string City { get; set; }
}

using ETLBox.DbExtensions;

var connection = new SqlConnection("your-connection-string");
var customers = Enumerable.Range(1, 10_000)
    .Select(i => new Customer { Id = i, Name = $"Customer {i}", City = "Merged City" });
connection.BulkMerge(customers, options => {
    options.MergeMode = MergeMode.Full;
});

public class Customer : MergeableRow {
    [IdColumn]
    public int Id { get; set; }
    public string Name { get; set; }
    public string City { get; set; }
}

using ETLBox.DbExtensions;

var connection = new SqlConnection("your-connection-string");
var customers = Enumerable.Range(1, 10_000)
    .Select(i => new Customer { Id = i, Name = $"Updated {i}" });
connection.BulkUpdate(customers);

public class Customer {
    [IdColumn]
    public int Id { get; set; }
    public string Name { get; set; }
    public string City { get; set; }
}

using ETLBox.DbExtensions;

var connection = new SqlConnection("your-connection-string");
var customers = Enumerable.Range(1, 10_000)
    .Select(i => new Customer { Id = i });
connection.BulkDelete(customers);

public class Customer {
    [IdColumn]
    public int Id { get; set; }
    public string Name { get; set; }
    public string City { get; set; }
}

Works with the databases you already use

SQL Server

PostgreSQL

MySQL

MariaDB

SQLite

Oracle

Snowflake

Also IBM Db2, SAP HANA, SAP ASE, and any ADO.NET provider with an ETLBox connector.

Works with Dapper

Same idea as Dapper: we extend IDbConnection. Query with Dapper, write in bulk — one extra using, no new client.

Faster than a loop

Not just less code. A Dapper loop takes seconds; bulk load finishes the same 5,000 inserts in milliseconds.

Insert, update, delete, merge

Not just inserts. Change or remove many rows, or sync a whole table, with the same one-line style.

Keep tables in sync

New rows go in, existing rows are updated, missing rows can be deleted — without checking each record yourself.

Compare

	Dapper loop	SqlBulkCopy	DbExtensions
Insert	One round-trip per row	Fast, SQL Server only	One call, many databases
Update / delete	Same loop	Not included	`BulkUpdate` / `BulkDelete`
Upsert / sync	Select + insert or update	Not included	`BulkMerge`
API	SQL you already write	`DataTable` + column maps	Your POCOs on `IDbConnection`