DuckDB.NET

DuckDB bindings for C#

Usage

dotnet add package DuckDB.NET.Data.Full

using (var duckDBConnection = new DuckDBConnection("Data Source=file.db"))
{
  duckDBConnection.Open();

  using var command = duckDBConnection.CreateCommand();

  command.CommandText = "CREATE TABLE integers(foo INTEGER, bar INTEGER);";
  var executeNonQuery = command.ExecuteNonQuery();

  command.CommandText = "INSERT INTO integers VALUES (3, 4), (5, 6), (7, 8);";
  executeNonQuery = command.ExecuteNonQuery();

  command.CommandText = "Select count(*) from integers";
  var executeScalar = command.ExecuteScalar();

  command.CommandText = "SELECT foo, bar FROM integers";
  var reader = command.ExecuteReader();

  PrintQueryResults(reader);
}

private static void PrintQueryResults(DbDataReader queryResult)
{
  for (var index = 0; index < queryResult.FieldCount; index++)
  {
    var column = queryResult.GetName(index);
    Console.Write($"{column} ");
  }

  Console.WriteLine();

  while (queryResult.Read())
  {
    for (int ordinal = 0; ordinal < queryResult.FieldCount; ordinal++)
    {
      var val = queryResult.GetInt32(ordinal);
      Console.Write(val);
      Console.Write(" ");
    }

    Console.WriteLine();
  }
}

MotherDuck

To connect to MotherDuck:

using var duckDBConnection = new DuckDBConnection("DataSource=md:{your_database}?motherduck_token=ey...");

DuckDB Extensions (C#)

If you want to build DuckDB extensions with C#, see Giorgi/DuckDB.ExtensionKit.

Known Issues

When debugging your project that uses DuckDB.NET library, you may get the following error: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. The error happens due to debugger interaction with the native memory. For a workaround check out Debugger Options mess up debugging session during Marshalling

Documentation

Documentation is available at https://duckdb.net

Support

If you encounter a bug with the library Create an Issue. Join the DuckDB dotnet channel for DuckDB.NET-related topics.

Contributors

Sponsors

A big thanks to DuckLabs and AWS Open Source Software Fund for sponsoring the project!