Hi there! If you’re reading this article, you’re probably wondering about the compatibility level of SQL Server and what it means for your database. Compatibility level is an important consideration for database administrators and developers when upgrading to a new version of SQL Server. In this article, we’ll cover everything you need to know about compatibility level, including what it is, why it’s important, and how to change it.
What is Compatibility Level?
At its most basic level, compatibility level is a setting in SQL Server that determines how much of the functionality of previous versions of SQL Server is supported. In other words, it allows you to run your database in a mode that is compatible with an earlier version of SQL Server.
For example, if you have a database that was created in SQL Server 2008, you might want to set the compatibility level to SQL Server 2008 when you upgrade to SQL Server 2017. This will ensure that the database operates as it did in SQL Server 2008 and that any applications that rely on the database continue to function properly.
How is Compatibility Level Determined?
The compatibility level of a database is determined by the version of SQL Server that the database was originally created on. For example, if you create a database in SQL Server 2008, the compatibility level will be set to SQL Server 2008 by default.
However, it’s important to note that compatibility level can be changed after a database is created. This allows you to switch to a different compatibility level if needed, such as when upgrading to a new version of SQL Server.
Why is Compatibility Level Important?
Compatibility level is important because it determines how much of the functionality of previous versions of SQL Server is supported. If you’re upgrading to a new version of SQL Server, you need to be aware of the compatibility level of your databases to ensure that they will work properly.
Additionally, compatibility level can affect performance. Some features that are supported in newer versions of SQL Server may not be available in older compatibility modes, which can impact the performance of your database.
How to Change Compatibility Level
If you need to change the compatibility level of a database, the process is relatively simple. Here’s how to do it:
Step 1: Connect to your SQL Server instance
To change the compatibility level of a database, you’ll need to connect to your SQL Server instance using SQL Server Management Studio (SSMS) or a similar tool.
Step 2: Select the database you want to change
Once you’re connected to your SQL Server instance, select the database that you want to change the compatibility level for.
Step 3: Right-click on the database and select Properties
Right-click on the database you want to change the compatibility level for and select Properties from the context menu.
Step 4: Select Options from the left-hand menu
In the Properties window, select Options from the left-hand menu.
Step 5: Change the Compatibility Level setting
In the Options section, you’ll see a Compatibility Level setting. Click on the drop-down menu and select the compatibility level that you want to use.
Step 6: Save your changes
Once you’ve selected the new compatibility level, click the OK button to save your changes.
FAQs
What are the different compatibility levels in SQL Server?
SQL Server supports several different compatibility levels, including:
| Compatibility Level | Description |
|---|---|
| 80 | SQL Server 2000 (default for databases upgraded from SQL Server 2000 or earlier) |
| 90 | SQL Server 2005 |
| 100 | SQL Server 2008 |
| 110 | SQL Server 2012 |
| 120 | SQL Server 2014 |
| 130 | SQL Server 2016 |
| 140 | SQL Server 2017 |
Can I downgrade the compatibility level of a database?
No, once you upgrade the compatibility level of a database, you cannot downgrade it. However, you can create a new database with the lower compatibility level and then transfer the data and objects from the old database to the new one.
Will changing the compatibility level of my database affect performance?
Yes, changing the compatibility level can affect performance. Some features that are supported in newer versions of SQL Server may not be available in older compatibility modes, which can impact the performance of your database.
What should I do if my application is not compatible with the latest compatibility level?
If your application is not compatible with the latest compatibility level, you may need to use an older compatibility level or modify your application to work with the latest version of SQL Server.
What is the default compatibility level for a new database?
The default compatibility level for a new database depends on the version of SQL Server that you’re using. For example, if you create a new database in SQL Server 2017, the default compatibility level will be 140.
Conclusion
The compatibility level of SQL Server is an important consideration for database administrators and developers when upgrading to a new version. By understanding what compatibility level is, why it’s important, and how to change it, you can ensure that your databases continue to function properly and that your applications work as intended. If you have any questions or need further assistance, please consult the official Microsoft documentation or reach out to a qualified SQL Server professional.