Bulk operations for the connection you already use

Dapper for reads. Bulk for writes.

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

Dapper is excellent at reading data. It is not a bulk writer. The usual workaround — a loop of INSERT / UPDATE / DELETE — costs one round-trip per row and gets slow as soon as the set grows. ETLBox.DbExtensions adds BulkInsert, BulkUpdate, BulkDelete, and BulkMerge to the same connection. One extra using. No new client. If the class you already use is SqlBulkCopy, see Beyond SqlBulkCopy.

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.

Dapper loop vs SqlBulkCopy vs DbExtensions

DbExtensions does not replace Dapper, and it does not pretend SqlBulkCopy is slow. It covers the write operations Dapper never added — on more than SQL Server.

DbExtensions

One line, many databases

Same IDbConnection as Dapper
Insert, update, delete, merge
Your POCOs — no DataTable
SQL Server, Postgres, MySQL, Oracle, SQLite, …
Same bulk engine as ETLBox data flows

Dapper loop

One round-trip per row

Great for queries, not for bulk writes
foreach + Execute does not scale
Merge becomes select-then-insert-or-update
SqlBulkCopy is insert-only, SQL Server only
A second client is more than you asked for

SQL Server, 5,000 rows

Measured with the open benchmark in etlbox.demo. Read the table as order of magnitude, not a guarantee.

	Dapper loop	SqlBulkCopy	DbExtensions
Insert	7.9 s — one round-trip per row	20 ms — SQL Server only	70 ms — POCOs, many databases
Update / delete	Same loop, ~7.5 s	Not included	BulkUpdate / BulkDelete
Upsert / sync	Select + insert or update, 11.6 s	Not included	BulkMerge — 0.28 s
API	SQL you already write, row by row	DataTable + column maps	Your POCOs on IDbConnection

Method, script, and caveats: 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; }
}

Try DbExtensions

Keep Dapper. Add bulk writes.

The product site has the docs, the trial, and pricing. NuGet without a key is limited to 5,000 rows. A trial key removes the limit for 45 days.

Get started Get a free trial key See pricing