In SQL, collation refers to the set of rules that determine how string data (like text) is stored and compared in the database. It affects things like:
Sorting:
How alphabetic characters are ordered. For example, whether uppercase letters come before lowercase ones, or if accents (like é vs. e) matter.
Comparing: How strings are compared to each other (for equality or other operations), like checking if “apple” is equal to “Apple.”
Character Set: Defines which set of characters can be stored, such as English letters, special symbols, or non-Latin characters.
Key Points:
Case sensitivity: Some collations are case-sensitive (e.g., “A” ≠“a”), while others are not.
Accent sensitivity: Some collations treat characters with accents as different from those without, while others do not.
For example, in SQL Server, the collation Latin1_General_CI_AS means:
CI: Case-insensitive
AS: Accent-sensitive
Different databases may use different default collations, but they can be set or changed when creating tables or databases.
