Bulk C# datatable to postgresql table

Question

I have got a datatable with thousands of records. I have got a postgres table with the same fields of the datatable. I want everyday to truncate this table and fill again wi

Answer 1

PostgreSQL definitely does have a bulk copy (it's actually called copy), and it has a nice wrapper for .NET. If you are loading, you want to use the NpgsqlCopyIn, and if you are extracting data you can use NpgsqlCopyOut.

Your question is a little vague on details -- I don't know the fields in your datatable or anything about your actual database, so take this as a brief example on how to bulk insert data into a table using C#/PostgreSQL:

    NpgsqlCopyIn copy = new NpgsqlCopyIn("copy table1 from STDIN WITH NULL AS '' CSV;",
        conn);
    copy.Start();

    NpgsqlCopySerializer cs = new NpgsqlCopySerializer(conn);
    cs.Delimiter = ",";

    foreach (var record in RecordList)
    {
        cs.AddString(record.UserId);
        cs.AddInt32(record.Age);
        cs.AddDateTime(record.HireDate);
        cs.EndRow();
    }

    cs.Close();
    copy.End();

-- Edit 8/27/2019 --

The construct for Npgsql has completely changed. Below is a boilerplate for the same example above, using binary import (text is also available):

using (var writer = conn.BeginBinaryImport(
    "copy user_data.part_list from STDIN (FORMAT BINARY)"))
{
    foreach (var record in RecordList)
    {
        writer.StartRow();
        writer.Write(record.UserId);
        writer.Write(record.Age, NpgsqlTypes.NpgsqlDbType.Integer);
        writer.Write(record.HireDate, NpgsqlTypes.NpgsqlDbType.Date);
    }

    writer.Complete();
}