Difference Between SqlConnection and IDbConnection

Difference Between SqlConnection and IDbConnection

Both and are used for database connections in .NET, but they serve different purposes.

1️⃣ IDbConnection (Interface)

• is an interface defined in the namespace.

• It provides a database-agnostic way to work with relational databases.

• It does not implement any actual database connection logic; it's just a contract that defines common methods like , , , etc.

• Used when you want flexibility to support different database providers (SQL Server, MySQL, PostgreSQL, etc.).

Example: Using IDbConnection for Database Agnostic Code

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🔹 Here, can be any database provider, making the code flexible.

2️⃣ SqlConnection (Concrete Class)

• is a concrete implementation of , specifically for SQL Server.

• It lives in (or in newer versions).

• Implements the actual logic to establish a SQL Server database connection.

• Provides additional SQL Server-specific features, like for fast inserts.

Example: Using SqlConnection for SQL Server

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🔹 Here, the repository only works with SQL Server.

📌 Key Differences

Feature (Interface) (Concrete Class)TypeInterfaceClassDatabase-Agnostic✅ Yes (Can work with any DB)❌ No (Only for SQL Server)Namespace (or )Instantiation❌ Cannot be instantiated✅ Can be instantiated ()Supports Other Databases✅ Yes (MySQL, PostgreSQL, Oracle, etc.)❌ No (SQL Server Only)

When to Use What?

ScenarioUse Use Want to support multiple databases✅ Yes❌ NoOnly using SQL Server❌ No✅ YesWriting generic repository✅ Yes❌ NoNeed SQL Server specific features❌ No✅ Yes

💡 Best Practice: Use IDbConnection with Dependency Injection

To make your code database-agnostic, inject instead of :

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Then register it in Dependency Injection (DI):

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This makes it easier to swap databases (e.g., replace with ).

Summary

• → Database-agnostic, interface for flexibility.

• → SQL Server-specific, concrete class for direct use.

• Use in repositories for better maintainability and flexibility.

Would you like a generic DB connection factory to switch between SQL Server, MySQL, and PostgreSQL dynamically?