Quickstart: Use .NET (C#) to connect and query data in Azure Database for PostgreSQL flexible server

This quickstart demonstrates how to connect to an Azure Database for PostgreSQL flexible server by using a C# application. It shows how to use SQL statements to query, insert, update, and delete data in the database. The steps in this article assume that you're familiar with developing by using C#, and that you're new to working with Azure Database for PostgreSQL.

Prerequisites

For this quickstart, you need:

An Azure account with an active subscription. Create an account for free.
Create an Azure Database for PostgreSQL flexible server instance, if you do not have one.
Use the empty postgres database available on the server or create a new database.
Install the .NET SDK for your platform (Windows, Ubuntu Linux, or macOS) for your platform.
Install Visual Studio to build your project.
Install Npgsql NuGet package in Visual Studio.

Get connection information

Get the connection information needed to connect to the Azure Database for PostgreSQL flexible server. You need the fully qualified server name and authentication credentials.

Use the Azure portal:

From the left-hand menu in Azure portal, select All resources, and then search for the server you created.
Select the server name.
In the resource menu, select Overview.
Copy the values shown as Endpoint and Administrator login.
If you forget the password for the administrator authentication, reset it by using the Reset password button.

Step 1: Connect and insert data

Use the following code to connect and load the data by using CREATE TABLE and INSERT INTO SQL statements. The code uses the NpgsqlCommand class with these methods:

Open() to establish a connection to the Azure Database for PostgreSQL flexible server database.
CreateCommand() to set the CommandText property.
ExecuteNonQuery() method to run the database commands.

Important

Replace the Host, DBName, User, and Password parameters with the values that you specified when you created the server and database.

using System;
using Npgsql;

namespace Driver
{
    public class AzurePostgresCreate
    {
        // Obtain connection string information from the portal
        //
        private static string Host = "mydemoserver.postgres.database.azure.com";
        private static string User = "mylogin";
        private static string  DBname = "postgres";
        private static string Password = "<server_admin_password>";
        private static string Port = "5432";

        static void Main(string[] args)
        {
            // Build connection string using parameters from portal
            //
            string connString =
                String.Format(
                    "Server={0};Username={1};Database={2};Port={3};Password={4};SSLMode=Prefer",
                    Host,
                    User,
                    DBname,
                    Port,
                    Password);


            using (var conn = new NpgsqlConnection(connString))

            {
                Console.Out.WriteLine("Opening connection");
                conn.Open();

                using (var command = new NpgsqlCommand("DROP TABLE IF EXISTS inventory", conn))
                {
                    command.ExecuteNonQuery();
                    Console.Out.WriteLine("Finished dropping table (if existed)");

                }

                using (var command = new NpgsqlCommand("CREATE TABLE inventory(id serial PRIMARY KEY, name VARCHAR(50), quantity INTEGER)", conn))
                {
                    command.ExecuteNonQuery();
                    Console.Out.WriteLine("Finished creating table");
                }

                using (var command = new NpgsqlCommand("INSERT INTO inventory (name, quantity) VALUES (@n1, @q1), (@n2, @q2), (@n3, @q3)", conn))
                {
                    command.Parameters.AddWithValue("n1", "banana");
                    command.Parameters.AddWithValue("q1", 150);
                    command.Parameters.AddWithValue("n2", "orange");
                    command.Parameters.AddWithValue("q2", 154);
                    command.Parameters.AddWithValue("n3", "apple");
                    command.Parameters.AddWithValue("q3", 100);

                    int nRows = command.ExecuteNonQuery();
                    Console.Out.WriteLine(String.Format("Number of rows inserted={0}", nRows));
                }
            }

            Console.WriteLine("Press RETURN to exit");
            Console.ReadLine();
        }
    }
}

Having any issues? Let us know.

Step 2: Read data

Use the following code to connect and read the data by using a SELECT SQL statement. The code uses the NpgsqlCommand class with these methods:

Open() to establish a connection to PostgreSQL.
CreateCommand() and ExecuteReader() to run the database commands.
Read() to advance to the record in the results.
GetInt32() and GetString() to parse the values in the record.

Important

Replace the Host, DBName, User, and Password parameters with the values that you specified when you created the server and database.

using System;
using Npgsql;

namespace Driver
{
    public class AzurePostgresRead
    {
        // Obtain connection string information from the portal
        //
        private static string Host = "mydemoserver.postgres.database.azure.com";
        private static string User = "mylogin";
        private static string  DBname = "postgres";
        private static string Password = "<server_admin_password>";
        private static string Port = "5432";

        static void Main(string[] args)
        {
            // Build connection string using parameters from portal
            //
            string connString =
                String.Format(
                    "Server={0}; User Id={1}; Database={2}; Port={3}; Password={4};SSLMode=Prefer",
                    Host,
                    User,
                    DBname,
                    Port,
                    Password);

            using (var conn = new NpgsqlConnection(connString))
            {

                Console.Out.WriteLine("Opening connection");
                conn.Open();


                using (var command = new NpgsqlCommand("SELECT * FROM inventory", conn))
                {

                    var reader = command.ExecuteReader();
                    while (reader.Read())
                    {
                        Console.WriteLine(
                            string.Format(
                                "Reading from table=({0}, {1}, {2})",
                                reader.GetInt32(0).ToString(),
                                reader.GetString(1),
                                reader.GetInt32(2).ToString()
                                )
                            );
                    }
                    reader.Close();
                }
            }

            Console.WriteLine("Press RETURN to exit");
            Console.ReadLine();
        }
    }
}

Having any issues? Let us know.

Step 3: Update data

Use the following code to connect to the database and update the data by using an UPDATE SQL statement. The code uses the NpgsqlCommand class with the following methods:

Open() to establish a connection to the Azure Database for PostgreSQL flexible server.
CreateCommand() to set the CommandText property.
ExecuteNonQuery() method to run the database commands.

Important

Replace the Host, DBName, User, and Password parameters with the values that you specified when you created the server and database.

using System;
using Npgsql;

namespace Driver
{
    public class AzurePostgresUpdate
    {
        // Obtain connection string information from the portal
        //
        private static string Host = "mydemoserver.postgres.database.azure.com";
        private static string User = "mylogin";
        private static string  DBname = "postgres";
        private static string Password = "<server_admin_password>";
        private static string Port = "5432";

        static void Main(string[] args)
        {
            // Build connection string using parameters from portal
            //
            string connString =
                String.Format(
                    "Server={0}; User Id={1}; Database={2}; Port={3}; Password={4};SSLMode=Prefer",
                    Host,
                    User,
                    DBname,
                    Port,
                    Password);

            using (var conn = new NpgsqlConnection(connString))
            {

                Console.Out.WriteLine("Opening connection");
                conn.Open();

                using (var command = new NpgsqlCommand("UPDATE inventory SET quantity = @q WHERE name = @n", conn))
                {
                    command.Parameters.AddWithValue("n", "banana");
                    command.Parameters.AddWithValue("q", 200);
                    int nRows = command.ExecuteNonQuery();
                    Console.Out.WriteLine(String.Format("Number of rows updated={0}", nRows));
                }
            }

            Console.WriteLine("Press RETURN to exit");
            Console.ReadLine();
        }
    }
}

Having any issues? Let us know.

Step 4: Delete data

Use the following code to connect to the database and delete data by using a DELETE SQL statement.

The code uses the NpgsqlCommand class with the Open() method to establish a connection to the Azure Database for PostgreSQL flexible server database. Then, the code uses the CreateCommand() method, sets the CommandText property, and calls the ExecuteNonQuery() method to run the database commands.

Important

Replace the Host, DBName, User, and Password parameters with the values that you specified when you created the server and database.

using System;
using Npgsql;

namespace Driver
{
    public class AzurePostgresDelete
    {
        // Obtain connection string information from the portal
        //
        private static string Host = "mydemoserver.postgres.database.azure.com";
        private static string User = "mylogin@mydemoserver";
        private static string  DBname = "postgres";
        private static string Password = "<server_admin_password>";
        private static string Port = "5432";

        static void Main(string[] args)
        {
            // Build connection string using parameters from portal
            //
            string connString =
                String.Format(
                    "Server={0}; User Id={1}; Database={2}; Port={3}; Password={4};SSLMode=Prefer",
                    Host,
                    User,
                    DBname,
                    Port,
                    Password);

            using (var conn = new NpgsqlConnection(connString))
            {
                Console.Out.WriteLine("Opening connection");
                conn.Open();

                using (var command = new NpgsqlCommand("DELETE FROM inventory WHERE name = @n", conn))
                {
                    command.Parameters.AddWithValue("n", "orange");

                    int nRows = command.ExecuteNonQuery();
                    Console.Out.WriteLine(String.Format("Number of rows deleted={0}", nRows));
                }
            }

            Console.WriteLine("Press RETURN to exit");
            Console.ReadLine();
        }
    }
}

Clean up resources

To clean up all resources used during this quickstart, delete the resource group by using the following command:

az group delete \
    --name $AZ_RESOURCE_GROUP \
    --yes

Feedback

Was this page helpful?

Last updated on 2026-07-14

Quickstart: Use .NET (C#) to connect and query data in Azure Database for PostgreSQL flexible server

Prerequisites

Get connection information

Step 1: Connect and insert data

Step 2: Read data

Step 3: Update data

Step 4: Delete data

Clean up resources

Related content

Feedback

Additional resources