Azure SQL Guide

Comprehensive documentation for Microsoft Azure SQL Database and SQL Server on Azure.

Introduction to Azure SQL

Azure SQL is a family of cloud-based database services from Microsoft, offering robust, scalable, and intelligent database solutions for modern applications. It combines the broadest set of SQL Server capabilities with the benefits of a fully managed cloud platform.

Azure SQL provides flexibility in choosing the right deployment option based on your application's needs, ranging from fully managed Platform-as-a-Service (PaaS) offerings to Infrastructure-as-a-Service (IaaS) solutions.

Getting Started

To begin your journey with Azure SQL, you'll need an Azure subscription. You can create one for free. Once you have your subscription, you can deploy your first Azure SQL resource through the Azure portal, Azure CLI, or PowerShell.

Quick Start: Explore our interactive quick start guides to deploy a basic Azure SQL Database in minutes.

Deployment Options

Azure SQL offers three primary deployment models, each with distinct advantages:

Azure SQL Database

Azure SQL Database is a fully managed PaaS offering that handles most database management functions like upgrading, patching, and backups without user involvement. It's ideal for modern cloud applications.

  • Benefits: High availability, automatic scaling, built-in security features, serverless compute.
  • Use Cases: Web and mobile apps, microservices, analytics, IoT.

Azure SQL Managed Instance

Azure SQL Managed Instance provides near 100% compatibility with on-premises SQL Server, offering a great option for lift-and-shift scenarios. It's a fully managed PaaS service within your Azure virtual network.

  • Benefits: Broad SQL Server engine compatibility, instance-level features (SQL Agent, cross-database queries), network isolation.
  • Use Cases: Migrating existing SQL Server applications with minimal changes, applications requiring instance-level features.

SQL Server on Azure Virtual Machines

This IaaS option allows you to run SQL Server in a virtual machine on Azure. You have full control over the operating system and SQL Server instance, similar to on-premises deployment.

  • Benefits: Full control, familiar environment, flexibility.
  • Use Cases: Applications with specific OS dependencies, hybrid scenarios, strict compliance requirements.

Database Management

Managing your Azure SQL resources is streamlined through various tools:

  • Azure Portal: A web-based graphical interface for managing all Azure resources.
  • Azure Data Studio: A modern, cross-platform database tool for developers and DBAs.
  • SQL Server Management Studio (SSMS): The traditional, powerful desktop tool for SQL Server management.
  • Azure CLI and PowerShell: For scripting and automation.

Key management tasks include monitoring performance, configuring backups, managing logins and users, and setting up alerts.

Performance Tuning

Optimizing the performance of your Azure SQL databases is crucial. Key areas include:

  • Indexing: Proper indexing can dramatically improve query execution times.
  • Query Optimization: Analyzing execution plans and rewriting inefficient queries.
  • Resource Provisioning: Choosing the right service tier and compute size for your workload (DTUs, vCores, Serverless).
  • Query Store: A feature that helps track query performance history and identify regressions.
  • Automatic Tuning: Azure SQL Database can automatically identify and fix performance issues.

Consider using tools like Query Performance Insight in the Azure portal.

Tip: Regularly review performance metrics and utilize the built-in performance analysis tools to proactively identify and resolve bottlenecks.

Security

Azure SQL offers a comprehensive suite of security features to protect your data:

  • Authentication: Azure Active Directory authentication, SQL authentication.
  • Authorization: Role-based access control, permissions.
  • Data Encryption: Transparent Data Encryption (TDE), Always Encrypted.
  • Network Security: Firewalls, Virtual Network service endpoints, Private Link.
  • Threat Detection: Advanced Threat Protection for Azure SQL Database.

Implement the principle of least privilege for all database users and applications.

High Availability & Disaster Recovery

Azure SQL services are designed with high availability and disaster recovery in mind.

  • High Availability: Azure SQL Database and Managed Instance offer built-in high availability, ensuring your database is accessible even if hardware failures occur.
  • Business Continuity: Features like active geo-replication and auto-failover groups enable robust disaster recovery strategies across different Azure regions.
  • Automated Backups: Regular automated backups are stored in Azure Blob Storage.

Migration Strategies

Migrating your on-premises SQL Server databases to Azure SQL can be achieved using various methods:

  • Azure Database Migration Service (DMS): A fully managed service that enables seamless migrations with minimal downtime.
  • Backup and Restore: For SQL Server on Azure VM or for specific scenarios.
  • Data-Tier Application Framework (DACPAC): For schema migration.
  • Transactional Replication: For near-zero downtime migrations.

The Microsoft Data Migration Assistant (DMA) can help assess your existing databases and recommend migration paths.

-- Example of a simple query
SELECT
    name,
    create_date,
    compatibility_level
FROM
    sys.databases
WHERE
    database_id > 4;