i am having database of 5gm with latin collation which support only english.i want to change this collision to arabic and english support.is it possiable what will be effect.
You mean your database size is 5gb, not in grams [] (I was wondering how you are able weigh your database?) Anyway changing collation is quite possible using ALTER DATABASE statement, you could get more information from updated Books online on the code examples to change. But it will have only affect for the new data, existing data should be recreated in order to take new affect. Within SQL Server you should be able to affect new collation on database/table/column level.
It's not just about collation, you have to use the unicode data types for strings (nvarchar instead of varchar, etc.) in order to support non-roman characters. So unless you already are using unicode data types, it can be a lot of work to change everything (columns, views, stored procedures, user-defined functions ...).
