What does collation mean?

Question

What does collation mean in SQL, and what does it do?

Answer 1

Collation defines how you sort and compare string values

For example, it defines how to deal with

• accents (äàa etc)
• case (Aa)
• the language context:
  • In a French collation, cote < côte < coté < côté.
  • In the SQL Server Latin1 default , cote < coté < côte < côté
• ASCII sorts (a binary collation)

Answer 2

Collation means assigning some order to the characters in an Alphabet, say, ASCII or Unicode etc.

Suppose you have 3 characters in your alphabet - {A,B,C}. You can define some example collations for it by assigning integral values to the characters

1. Example 1 = {A=1,B=2,C=3}
2. Example 2 = {C=1,B=2,A=3}
3. Example 3 = {B=1,C=2,A=3}

As a matter of fact, you can define n! collations on an Alphabet of size n. Given such an order, different sorting routines likes LSD/MSD string sorts make use of it for sorting strings.

Answer 3

http://en.wikipedia.org/wiki/Collation

Collation is the assembly of written information into a standard order. (...) A collation algorithm such as the Unicode collation algorithm defines an order through the process of comparing two given character strings and deciding which should come before the other.