C# and PostgreSQL: Complete Guide to Integration and Working with Databases

Why C# and PostgreSQL is a Powerful Combination Worth Mastering

The world of development is a constant choice. By choosing a language, framework, and database, we essentially lay the foundation for a future project. And if you've found this page, it means you're interested in one of the most powerful and modern stacks in enterprise development: C# and PostgreSQL.

Why this particular pair? C# is a mature, strongly typed language with a huge ecosystem and fantastic performance. PostgreSQL is an object-relational DBMS that surpasses many competitors in capabilities, stability, and support for complex data types (e.g., JSONB, arrays, full-text search). Together, they give you not just a "database and language," but a flexible, scalable tool for building web applications, microservices, and analytical systems.

In this guide, we won't just go through theory. We'll dive headfirst into practice: from installing the driver to writing complex transactions. You'll learn how to properly configure a connection, perform CRUD operations, use modern ORMs (Entity Framework Core and Dapper), and avoid common pitfalls. Let's go!

Step 1. Preparation: What You Need to Install

Before writing code, let's make sure you have everything you need.

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• PostgreSQL — download the latest version from the official website. During installation, remember the port (default 5432) and the password for the superuser postgres.
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• Visual Studio / Rider / VS Code — any IDE that supports .NET.
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• .NET SDK (6.0, 7.0, or 8.0) — the newer, the better. We'll use .NET 8.
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Now create a new project. For a console application, it's simple:

dotnet new console -n CsharpPostgresDemo\ncd CsharpPostgresDemo

The most important thing is to install the provider for PostgreSQL. In the .NET world, this is the Npgsql package (pronounced "En-pi-es-kyu-el"). It is the foundation for all other libraries.

dotnet add package Npgsql

Step 2. First Connection: Checking the Link

Let's create a simple script that connects to the database and outputs the server version. This is the best way to make sure everything works.

using Npgsql;\n\n// Connection string: enter your data\nstring connectionString = "Host=localhost;Port=5432;Database=postgres;Username=postgres;Password=your_password";\n\nusing var connection = new NpgsqlConnection(connectionString);\nconnection.Open();\n\n// Execute the query\nusing var command = new NpgsqlCommand("SELECT version();", connection);\nstring version = (string)await command.ExecuteScalarAsync();\n\nConsole.WriteLine($"Connection successful! PostgreSQL version: {version}");

Run the code. If you see something like "PostgreSQL 16.1 on x86_64-pc-linux-gnu..." in the console, you did it! If not, check the password, hostname, and make sure the PostgreSQL service is running.

Step 3. CRUD Operations in C# with PostgreSQL

Now that the connection works, let's create a table and perform the full cycle: Create, Read, Update, Delete.

Creating a Table

string createTableSql = @"\n    CREATE TABLE IF NOT EXISTS users (\n        id SERIAL PRIMARY KEY,\n        name VARCHAR(100) NOT NULL,\n        email VARCHAR(255) UNIQUE NOT NULL,\n        created_at TIMESTAMP DEFAULT NOW()\n    );";\n\nusing var cmdCreate = new NpgsqlCommand(createTableSql, connection);\nawait cmdCreate.ExecuteNonQueryAsync();\nConsole.WriteLine("Table users created.");

Inserting Data (INSERT)

// Use a parameterized query — this protects against SQL injection!\nstring insertSql = "INSERT INTO users (name, email) VALUES (@name, @email) RETURNING id;";\n\nusing var cmdInsert = new NpgsqlCommand(insertSql, connection);\ncmdInsert.Parameters.AddWithValue("@name", "Ale