What is collation? and What are different types of Collation Sensitivity in SQL Server?

What is collation?
Collation refers to a set of rules that determine how data is sorted and compared. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types and character width.

• Case sensitivity: If A and a, C and c, etc. are treated in the same way then it is case-insensitive. A computer treats A and a differently because it uses ASCII code to differentiate the input. The ASCII value of A is 65, while a is 97. The ASCII value of C is 67 and c is 99.

• Accent sensitivity: If e and é, o and ó are treated in the same way, then it is accent-insensitive. A computer treats a and á differently because it uses ASCII code for differentiating the input. The ASCII value of e is 101 and é is 130. The ASCII value of o is 111 and ó is 243.

• Kana Sensitivity: When Japanese kana characters Hiragana and Katakana are treated differently, it is called Kana sensitive.

• Width sensitivity: When a single-byte character (half-width) and the same character when represented as a double-byte character (full-width) are treated differently then it is width sensitive.