---
title: 'Quickstart: Connect with C#'
description: "This quickstart provides a C# (.NET) code sample you can use to connect and query data from Azure Database for PostgreSQL - Flexible Server."
ms.service: postgresql
ms.subservice: flexible-server
ms.author: maximagapov
author: agapovm
ms.custom: mvc, devcenter, devx-track-csharp, mode-other, devx-track-dotnet
ms.devlang: csharp
ms.topic: quickstart
ms.date: 01/23/2024
---

# Quickstart: Use .NET (C#) to connect and query data in Azure Database for PostgreSQL - Flexible Server

[!INCLUDE [applies-to-postgresql-flexible-server](../includes/applies-to-postgresql-flexible-server.md)]

This quickstart demonstrates how to connect to an Azure Database for PostgreSQL flexible server instance 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 are familiar with developing using C#, and that you are new to working with Azure Database for PostgreSQL flexible server.

## Prerequisites

For this quickstart you need:

- An Azure account with an active subscription. [Create an account for free](https://azure.microsoft.com/free).
- Create an Azure Database for PostgreSQL flexible server instance using [Azure portal](./quickstart-create-server-portal.md) <br/> or [Azure CLI](./quickstart-create-server-cli.md) if you do not have one.
- Use the empty *postgres* database available on the server or create a [new database](./quickstart-create-server-portal.md#connect-to-the-postgresql-database-using-psql).
- Install the [.NET SDK for your platform](https://dotnet.microsoft.com/download) (Windows, Ubuntu Linux, or macOS) for your platform.
- Install [Visual Studio](https://www.visualstudio.com/downloads/) to build your project.
- Install [Npgsql](https://www.nuget.org/packages/Npgsql/) NuGet package in Visual Studio.

## Get connection information

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

1. Log in to the [Azure portal](https://portal.azure.com/).
2. From the left-hand menu in Azure portal, click **All resources**, and then search for the server you have created (such as **mydemoserver**).
3. Click the server name.
4. From the server's **Overview** panel, make a note of the **Server name** and **Server admin login name**. If you forget your password, you can also reset the password from this panel.
 :::image type="content" source="./media/connect-csharp/1-connection-string.png" alt-text="Azure Database for PostgreSQL flexible server instance name.":::

## Step 1: Connect and insert data

Use the following code to connect and load the data using **CREATE TABLE** and  **INSERT INTO** SQL statements. The code uses NpgsqlCommand class with method:
- [Open()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_Open) to establish a connection to the Azure Database for PostgreSQL flexible server database.
- [CreateCommand()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_CreateCommand) sets the CommandText property.
- [ExecuteNonQuery()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlCommand.html#Npgsql_NpgsqlCommand_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.

```csharp
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.](https://github.com/MicrosoftDocs/azure-docs/issues)

## Step 2: Read data

Use the following code to connect and read the data using a **SELECT** SQL statement. The code uses NpgsqlCommand class with method:
- [Open()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_Open) to establish a connection to PostgreSQL.
- [CreateCommand()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_CreateCommand) and [ExecuteReader()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlCommand.html#Npgsql_NpgsqlCommand_ExecuteReader) to run the database commands.
- [Read()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlDataReader.html#Npgsql_NpgsqlDataReader_Read) to advance to the record in the results.
- [GetInt32()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlDataReader.html#Npgsql_NpgsqlDataReader_GetInt32_System_Int32_) and [GetString()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlDataReader.html#Npgsql_NpgsqlDataReader_GetString_System_Int32_) 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.

```csharp
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.](https://github.com/MicrosoftDocs/azure-docs/issues)


## Step 3: Update data

Use the following code to connect and update the data using an **UPDATE** SQL statement. The code uses NpgsqlCommand class with method:
- [Open()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_Open) to establish a connection to Azure Database for PostgreSQL flexible server.
- [CreateCommand()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_CreateCommand), sets the CommandText property.
- [ExecuteNonQuery()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlCommand.html#Npgsql_NpgsqlCommand_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.

```csharp
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.](https://github.com/MicrosoftDocs/azure-docs/issues)

## Step 4: Delete data

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

The code uses NpgsqlCommand class with method [Open()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_Open) to establish a connection to the Azure Database for PostgreSQL flexible server database. Then, the code uses the [CreateCommand()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlConnection.html#Npgsql_NpgsqlConnection_CreateCommand) method, sets the CommandText property, and calls the method [ExecuteNonQuery()](https://www.npgsql.org/doc/api/Npgsql.NpgsqlCommand.html#Npgsql_NpgsqlCommand_ExecuteNonQuery) 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.

```csharp
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 using the following command:

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

## Next steps

> [!div class="nextstepaction"]
> [Manage Azure Database for PostgreSQL server using Portal](./how-to-manage-server-portal.md)<br/>

> [!div class="nextstepaction"]
> [Manage Azure Database for PostgreSQL server using CLI](./how-to-manage-server-cli.md)