Standard Appender

The standard appender is a lower-level API that uses CreateAppender to efficiently add rows to the database. It requires manual row creation with CreateRow and AppendValue methods.

Use this approach for maximum performance when type safety is not needed, or when you need fine-grained control over the insertion process.

Caution

When using the standard appender, data types MUST match the length of the database types exactly. For example when inserting into a UBIGINTEGER column, a ulong such as 0UL must be used. Writing just 0 will cause data corruption by writing adjacent memory to the database.

Example

using var connection = new DuckDBConnection("DataSource=:memory:");
connection.Open();

using (var duckDbCommand = connection.CreateCommand())
{
  var table = "CREATE TABLE AppenderTest(foo INTEGER, bar INTEGER);";
  duckDbCommand.CommandText = table;
  duckDbCommand.ExecuteNonQuery();
}

var rows = 100;
using (var appender = connection.CreateAppender("AppenderTest"))
{
  for (var i = 0; i < rows; i++)
  {
    var row = appender.CreateRow();
    row.AppendValue(i).AppendValue(i+2).EndRow();
  }
}

Data Importing from Files

For importing data from CSV, Parquet, JSON and other file types see the DuckDB documentation for Data Importing.