what-is-sql-server.md

title	description	author	ms.author	ms.date	ms.service	ms.subservice	ms.topic
What is SQL Server?	An overview of the relational database engine and components of SQL Server	rwestMSFT	randolphwest	02/14/2024	sql	release-landing	conceptual

What is SQL Server?

[!INCLUDE sqlserver]

[!INCLUDE msconame-md] [!INCLUDE ssnoversion-md] is a relational database management system (RDBMS). Applications and tools connect to a [!INCLUDE ssnoversion-md] instance or database, and communicate using Transact-SQL (T-SQL).

Deployment options

You can install [!INCLUDE ssnoversion-md] on Windows or Linux, deploy it in a Linux container, or deploy it on an Azure Virtual Machine or other virtual machine platform. You previously might have referred to this as the boxed product.

Supported versions of [!INCLUDE ssnoversion-md] depend on your license agreement, but for the purposes of this documentation, we mean [!INCLUDE sssql16-md] and later versions. Documentation for [!INCLUDE sssql14-md] and previous versions is available at Previous versions of SQL Server documentation. To find out which versions of [!INCLUDE ssnoversion-md] are currently supported, see SQL Server end of support options.

The underlying [!INCLUDE ssdenoversion-md] is also used by the following products and services:

• [[!INCLUDE ssazure-sqldb]](/azure/azure-sql/database/sql-database-paas-overview)
• [[!INCLUDE ssazuremi-md]](/azure/azure-sql/managed-instance/sql-managed-instance-paas-overview)
• Microsoft Analytics Platform System (PDW)
• [[!INCLUDE ssazuresynapse-md]](/azure/synapse-analytics/overview-what-is)
• [[!INCLUDE ssazurede-md]](/azure/azure-sql-edge/overview)

[!INCLUDE editions-supported-features-windows]

SQL Server components and technologies

This section describes some of the key technologies available in [!INCLUDE ssnoversion-md].

Component	Description
Database Engine	The [!INCLUDE ssde-md] is the core service for storing, processing, and securing data. The [!INCLUDE ssde-md] provides controlled access and transaction processing to meet the requirements of the most demanding data consuming applications within your enterprise. The [!INCLUDE ssde-md] also provides rich support for sustaining business continuity through Business continuity and database recovery - SQL Server.
Machine Learning Services (MLS)	SQL Server Machine Learning Services supports integration of machine learning, using the popular R and Python languages, into enterprise workflows. Machine Learning Services (In-Database) integrates R and Python with [!INCLUDE ssnoversion-md], making it easy to build, retrain, and score models by calling stored procedures. Machine Learning Server provides enterprise-scale support for R and Python, without requiring [!INCLUDE ssnoversion-md].
Integration Services (SSIS)	SQL Server Integration Services is a platform for building high performance data integration solutions, including packages that provide extract, transform, and load (ETL) processing for data warehousing.
Analysis Services (SSAS)	SQL Server Analysis Services is an analytical data platform and toolset for personal, team, and corporate business intelligence. Servers and client designers support traditional OLAP solutions, new tabular modeling solutions, as well as self-service analytics and collaboration using [!INCLUDE power-pivot-md], Excel, and a SharePoint Server environment. [!INCLUDE ssASnoversion] also includes Data Mining so that you can uncover the patterns and relationships hidden inside large volumes of data.
Reporting Services (SSRS)	SQL Server Reporting Services delivers enterprise, Web-enabled reporting functionality. You can create reports that draw content from various data sources, publish reports in various formats, and centrally manage security and subscriptions.
Replication	SQL Server Replication is a set of technologies for copying and distributing data and database objects from one database to another, and then synchronizing between databases to maintain consistency. By using replication, you can distribute data to different locations and to remote or mobile users with local and wide area networks, dial-up connections, wireless connections, and the Internet.
Data Quality Services (DQS)	Data Quality Services provides you with a knowledge-driven data cleansing solution. DQS enables you to build a knowledge base, and then use that knowledge base to perform data correction and deduplication on your data, using both computer-assisted and interactive means. You can use cloud-based reference data services, and you can build a data management solution that integrates DQS with [!INCLUDE ssnoversion-md] Integration Services and Master Data Services.
Master Data Services (MDS)	Master Data Services is the [!INCLUDE ssNoVersion] solution for master data management. A solution built on [!INCLUDE ssMDSshort] helps ensure that reporting and analysis are based on the right information. Using [!INCLUDE ssMDSshort], you create a central repository for your master data and maintain an auditable, securable record of that data as it changes over time.

Fundamental concepts

This table provides links to fundamental concepts in [!INCLUDE ssnoversion-md] and Azure SQL.

Area	More information
Data files and the transaction log	- Database Files and Filegroups - System Databases - The transaction log
Database compatibility levels	- Compatibility certification - View or change the compatibility level of a database - ALTER DATABASE (Transact-SQL) compatibility level
Tables and views	- Tables - Views
Functions and stored procedures	- What are the SQL database functions? - Stored procedures (Database Engine)
Indexes	- Indexes - SQL Server and Azure SQL index architecture and design guide
Configure cost threshold for parallelism and maximum degree of parallelism	- Configure the cost threshold for parallelism - Configure the max degree of parallelism
Memory management	- Server memory configuration options - Memory management architecture guide
Checkpoints, startup, and crash recovery	- Database checkpoints - Accelerated database recovery
Back up and restore databases	- Back Up and Restore of SQL Server Databases - Transaction log backups
Manage SQL Server services	- Manage the Database Engine Services - SQL Server Configuration Manager - Start, stop, pause, resume, and restart SQL Server services - Add Features to an Instance of SQL Server (Setup)
Database console commands (DBCC)	- DBCC (Transact-SQL) - DBCC HELP (Transact-SQL) - DBCC CHECKDB (Transact-SQL)
High availability (HA) and disaster recovery (DR)	- Business continuity and database recovery - About log shipping - Failover Clustering and Always On Availability Groups - What is an Always On availability group?
Query processing and performance tuning	- Tune performance with the Query Store - Query processing architecture guide - Optimized locking - Transaction locking and row versioning guide

Connect to SQL Server

• Connect to the Database Engine
• What is SQL Server Management Studio (SSMS)?
• What is Azure Data Studio?

Azure integration

Although [!INCLUDE ssnoversion-md] is a standalone product, which can be installed on computers running Windows and Linux operating systems, you can integrate your [!INCLUDE ssnoversion-md] instances with several Azure services.

Azure Virtual Machines

SQL Server on Azure Virtual Machines enables you to use full versions of [!INCLUDE ssnoversion-md] in the cloud without having to manage any on-premises hardware. [!INCLUDE ssnoversion-md] virtual machines (VMs) also simplify licensing costs when you pay as you go.

Azure virtual machines run in many different geographic regions around the world. They also offer various machine sizes. The virtual machine image gallery allows you to create a [!INCLUDE ssnoversion-md] VM with the right version, edition, and operating system. This makes virtual machines a good option for many different [!INCLUDE ssnoversion-md] workloads.

Azure Arc

SQL Server enabled by Azure Arc simplifies governance and management by delivering a consistent multicloud and on-premises management platform. Azure Arc provides a centralized, unified way to manage your entire environment together, combining existing non-Azure and/or on-premises virtual machines, Kubernetes clusters, and databases into Azure Resource Manager.

You can use Azure services and management capabilities, introduce DevOps practices to support new cloud native patterns in your environment, and configure custom locations as an abstraction layer on top of Azure Arc-enabled Kubernetes clusters and cluster extensions, regardless of where your resources live.

Azure Kubernetes Service (AKS)

Azure Kubernetes Service (AKS) is a managed Kubernetes service for deploying and managing container clusters. With [!INCLUDE ssnoversion-md] on Linux containers, you can deploy a SQL Server Linux container to AKS using Helm charts.

Note

You can also set up SQL Managed Instance enabled by Azure Arc on a Kubernetes infrastructure of your choice, which allows you to manage the service in Azure while your data stays in the location you prefer.

Migrate and move data

[!INCLUDE ssnoversion-md] provides many opportunities to migrate and modernize your data estate.

Migrating to the cloud

• Migrate SQL Server workloads (FAQ)
• Import and Export Data with the SQL Server Import and Export Wizard
• Azure Database Migration Guides

Migrating to SQL Server

• Migrate databases and structured data to SQL Server on Linux ¹
• Data Migration Assistant
• Import data from Excel to SQL Server or Azure SQL Database
• SQL Server Migration Assistant

¹ [!INCLUDE sssql17-md] and later versions.

Update your version of SQL Server

• Latest updates and version history for SQL Server

Samples

• Wide World Importers sample databases
• AdventureWorks sample databases
• SQL Server samples on GitHub

[!INCLUDE get-help-options]

Related content

• SQL Server installation guide (Windows)
• Installation guidance for SQL Server on Linux
• Configure and customize SQL Server Docker containers
• Server configuration options (SQL Server)