Develop Database Engine

Introduction

The SQL Server Database Engine provides a robust runtime for storing, processing, and securing data. This guide helps developers extend and embed the engine, create custom components, and integrate with existing applications.

Engine Architecture

The engine consists of several core subsystems:

Storage Engine – manages files, pages, and buffering.
Query Processor – parses, optimizes, and executes T‑SQL statements.
Transaction Manager – enforces ACID properties.
Security Manager – controls authentication and authorization.

+-------------------+
|   Query Processor |
+-------------------+
         |
+-------------------+
|   Storage Engine  |
+-------------------+

Extensibility Points

Developers can plug into the engine through:

CLR Integration – host managed code inside the engine.
Extended Stored Procedures – call native DLL functions.
Custom Data Types – define user‑defined types (UDTs).
Full‑Text Filters – process custom document formats.

Key APIs

Below are the most commonly used APIs for engine development.

// Example: Register a CLR stored procedure
using System.Data;
using System.Data.SqlClient;
using Microsoft.SqlServer.Server;

public class MyProcedures
{
    [SqlProcedure]
    public static void HelloWorld()
    {
        SqlContext.Pipe.Send("Hello, SQL Server!");
    }
}

Refer to the SQL CLR Reference for detailed signatures.

Sample Code

Explore these samples to get started quickly:

Best Practices

Validate all inputs when writing extended procedures.
Prefer CLR integration over native code for safety and portability.
Use proper exception handling to avoid engine crashes.
Implement comprehensive logging via SqlContext.Pipe.

Microsoft Docs