Using Dapper with SQL Server: A Practical Guide

What is Dapper?

Dapper is a lightweight micro-ORM that extends IDbConnection interface in .NET, allowing you to execute SQL queries and map results to strongly typed objects easily.

Unlike full-featured ORMs, Dapper does not track changes or generate SQL for you. Instead, it focuses on fast execution and simple mapping.

• Open-source and maintained by Stack Exchange.
• Works with any database supported by ADO.NET, including SQL Server.
• Minimal overhead and excellent performance.
• Supports parameterized queries to prevent SQL injection.

Setting Up Dapper with SQL Server

To use Dapper, first install the Dapper NuGet package in your .NET project.

Then, establish a connection to your SQL Server database using SqlConnection from System.Data.SqlClient.

• Install Dapper via NuGet: `Install-Package Dapper` or `dotnet add package Dapper`.
• Use `using (var connection = new SqlConnection(connectionString))` to open a connection.
• Ensure your connection string is correctly configured for your SQL Server instance.

Basic CRUD Operations with Dapper

Dapper simplifies executing SQL commands and mapping query results to objects.

You can perform Create, Read, Update, and Delete operations using simple methods.

• Use `Query<T>()` to retrieve multiple records mapped to a list of objects.
• Use `QuerySingle<T>()` or `QueryFirst<T>()` for single record retrieval.
• Use `Execute()` for commands that do not return results, like INSERT, UPDATE, DELETE.

Performance and Use Cases

Dapper is known for its speed and low overhead, making it suitable for applications where performance is critical.

It is often used in microservices, APIs, and applications where full ORM features are unnecessary.

• Minimal abstraction over raw SQL.
• No change tracking or lazy loading.
• Best for scenarios requiring direct SQL control and fast data access.

Best Practices When Using Dapper

To get the most out of Dapper, follow these best practices.

• Always use parameterized queries to avoid SQL injection.
• Keep SQL queries organized and maintainable, possibly using stored procedures.
• Reuse database connections efficiently with connection pooling.
• Map only the necessary columns to your objects to improve performance.
• Handle exceptions and errors gracefully during database operations.