.NET

Prerequisites

Before you begin, make sure you have:

• A database account created for your PolarDB cluster. See Create a database account.

• The IP address of your application host added to an IP address whitelist of the cluster. See Configure a whitelist for a cluster.

Background information

.NET is a software framework developed by Microsoft that provides a comprehensive programming environment for building and running applications. The first version of the .NET Framework was released in 2002. It provided a unified programming model and supported multiple programming languages. The .NET Framework has now been extended to support a variety of platforms, including Linux and macOS.

PolarDB supports .NET programs of the following versions: .NET 2.0, .NET 3.5, .NET 4.0, .NET 5.0, .NET 6.0, .NET 7.0, .NET 8.0, .NET Core 3.1, .NET Standard 2.0, and .NET Standard 2.1.

Step 1: Install the driver

Download the DLL files from the table below based on your .NET version and the Npgsql version you need.

For .NET 2.0, 3.5, and 4.0, download both Mono.Security.dll and Npgsql.dll. For all other versions, only Npgsql.dll is required.

Entity Framework Core 5.0.10 is included in the .NET Standard 2.1 package for Npgsql 5.0.10. It provides platform support for .NET 2.0 through 7.0.

Step 2: Build the connection string

Connection strings use the keyword1=value; keyword2=value; format and are case-insensitive. Enclose values that contain semicolons (;) in double quotation marks (").

To find your cluster endpoint, see View or apply for an endpoint.

Step 3: Connect and run a query

The following example connects to the cluster and queries the current date:

using Npgsql;

var connString = "Host=xxxx;Port=xxxx;Username=xxx;Password=xxx;Database=xxxx";

await using var conn = new NpgsqlConnection(connString);
await conn.OpenAsync();

// Retrieve all rows
await using (var cmd = new NpgsqlCommand("SELECT sysdate FROM dual", conn))
await using (var reader = await cmd.ExecuteReaderAsync())
{
    while (await reader.ReadAsync())
        Console.WriteLine(reader.GetDateTime(0));
}

Sample result:

Troubleshooting

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    => optionsBuilder
        .UseNpgsql(...)
        .UseSnakeCaseNamingConvention();

case OracleDbType.Date:
  return NpgsqlDbType.Date;

case OracleDbType.Date:
  return NpgsqlDbType.Sysdate;

Release notes