Terms, conditions, and license calculation
How to navigate SQL Server licensing: basic terminology, how to license, the number of executable instances, and license calculation..
SQL Server is a reletional DBMS (Database Management System) developed by Microsoft and is used to manage databases of a wide variety of sizes and structuresAlong with Oracle Database and MySQL, it is one of the most widely used database platforms in the world because of its features and functionality for storing, processing, analyzing, and securing data.
It can be used for various purposes, such as application development, running Web sites, hosting data warehouses, or supporting business intelligence solutions. Among MS products, it is often considered the most "hostile" because of its non-simple and ever-changing licensing rules.
Before we delve into licensing for SQL Server, let us keep in mind that each version and edition of SQL has specific licensing terms, rights and features.
The basic terminology in reference to SQL Server
Let's take a closer look at the differences between edition and version and the functional features.
- Version: this is a distribution of SQL Server that is periodically updated with better features and performance and increased reliability and security. The latest public version is SQL Server 2022, available since January 2023, which Microsoft calls "the most Azure enabled release" meaning the release of SQL Server that is most prepared for Azure integration. Other earlier versions are 2019, 2017, 2016, 2014, etc.: for example, the 2014 version, formerly End Of Life (EOL), began the Extended Security Updates (ESUs) phase on July 9, 2024.
Almost always within multi-license contracts and CSPs you can take advantage of downgrade right, i.e., you have the right to use previously released versions without having to purchase them: for example, if you purchase the SQL Server 2022 product through MPSA today, you can downgrade your instance to any of the previous editions.
- Edition: these are the various types of SQL Server platform with different purposes, features and prices. The free editions available with the most up-to-date version of SQL Server are the Express e la Developer, while for a fee we find the Standard and Enterprise editions.Also available are a number of specialized editions such as Azure SQL Database, which is completely in the cloud, and also a Web Edition, a reduced total cost of ownership option for web hosting service providers, but this is only available through the Microsoft Services Provider License Agreement (SPLA).
Let's take a closer look at the main ones, dividing them into free and commercial:
Free Options
- Developer Edition: offers tools for developers, is completely free, to get it you have to register to download it. It is not allowed for any production workload, but only for development.
- Express Edition: this is a free edition with no special usage constraints but has technical limitations of memory and basic functionality suitable for embedded applications and small-scale projects.
Commercial options
- Standard ed Enterprise: these are the two main editions of SQL, which differ from each other in technical features.
The Standard, in fact, is best suited for simple projects where advanced data analysis, security and management features are not required; it is a cost-effective choice for deployments with moderate performance and scalability requirements.
The Enterprise Edition, on the other hand, includes all the basic features of the Standard Edition plus other tools typical of high-end databases with lightning-fast performance, unlimited virtualization, end-to-end business intelligence elements for the purpose of "enabling high service levels for crucial workloads and end-user access to detailed data information."
With regard to downgrading editions, there is a basic rule: If you assign a SQL Server Enterprise license to a host, you can run both a SQL Server Enterprise instance and a SQL Server Standard instance within it..
The reverse is not possible, however, because SQL Server Standard is an edition considered "smaller" and therefore cannot contain SQL Server Enterprise. The only exception to when just written is the AHB (Azure Hybrid Use Benefit) where it is possible to cover Enterprise instances with Standard licenses by applying a multiplier of 4 to the cores used (i.e., it takes 4 Standard cores to cover 1 Enterprise core).
Licensing model
The first and most important difference in terms of licensing between SQL Server Standard and SQL Enterprise is the licensing model. With the Standard edition, you can choose either the Server+CAL or per-core licensing model, while SQL Server Enterprise is available only through the per-core licensing model*.
Caution: the fact that SQL Server Standard Core and Enterprise Core licenses are sold in dual core packages can be confusing. If Microsoft is told that you want 88 licenses, considering that they are sold in dual core packages (and therefore two licenses), you may be buying twice as many.
As we anticipated earlier, licenses can be granted in two ways:
Server+CAL (server access license+client access licenses)
Currently, only SQL Server Standard has this licensing model.
Those who purchased SQL Server Enterprise licenses with the Server+CAL model before April 1, 2012 can still renew, regardless of whether or not the Software Assurance (SA) has been renewed, but they cannot purchase new licenses.
SQL licensing under the Client Access Licenses (CAL) model , as specified in the product's user rights, equires that each instance of SQL (virtual or physical) be covered by a single SQL Server license and that each user and/or device directly or indirectly accessing a licensed SQL Server must have a SQL Server CAL (user/ device CAL ) of the same or newer version. For example, to access a SQL Server 2019 Standard Edition server, a user will need a CAL of SQL Server 2019 or 2022.