When working with SQL Server, it’s important to understand the concept of case sensitivity, especially when it comes to data types and naming conventions. In this article, we will explore the implications of case sensitivity in SQL Server and how it can impact your database development.
The Case Sensitivity Issue
Many developers have their own coding conventions and habits when it comes to naming data types. However, it’s crucial to be aware of the case sensitivity of data types in SQL Server, as it can lead to unexpected issues.
For example, in a case-sensitive instance of SQL Server, uppercase and lowercase data type names may not be interchangeable. This can cause problems when declaring variables or calling methods on certain types.
Scenario: Case Sensitivity with CLR-Based Types
Let’s consider a scenario where we have a case-sensitive instance of SQL Server and we want to declare a variable of the CLR-based type “geography”.
If we declare the variable as “@x GeoGraphy;”, it will fail because the type name is case-sensitive. However, if we use the correct case, “@x geography;”, it will work without any issues.
This scenario highlights the importance of matching the case of type names when working with CLR-based types in SQL Server.
Scenario: Case Sensitivity with Alias Types
Alias types are user-defined types that can be created in SQL Server. These types can also be case-sensitive in certain scenarios.
For example, if we create an alias type called “Email” using the statement “CREATE TYPE dbo.Email FROM nvarchar(320);”, we need to ensure that we use the correct case when declaring variables, columns, or parameters with this type. Using the wrong case will result in an error.
Similarly, if we create a table type called “Ints” using the statement “CREATE TYPE dbo.Ints AS TABLE(i int PRIMARY KEY);”, we need to use the correct case when declaring variables of this type. Using the wrong case will also result in an error.
Best Practices
To avoid issues related to case sensitivity in SQL Server, it is recommended to follow these best practices:
- For built-in data types, always use lowercase.
- For user-defined types, such as alias or CLR types, rely on IntelliSense and verify that the case matches what’s defined in sys.types.
- Consider using binary collations during development to catch case sensitivity issues early on.
By adhering to these best practices, you can prevent surprises when deploying your database to an instance with a case- or binary-sensitive collation.
Understanding case sensitivity in SQL Server is essential for ensuring the consistency and reliability of your database applications. By being mindful of case sensitivity when working with data types and naming conventions, you can avoid potential issues and create more robust SQL Server solutions.
Article Last Updated: 2021-10-04