Hi thank you for reading my post why we should use Char when we have varchar? based on what i read in database books, if we define a char variable with length of 25 and store 5 characters into it, it will occupy 25 characters space in database, mean while varchar does not occupy the amount of space we determined for it. based on what i read, varchar occupied space is equal to number of characters that we really stored.
Raminaa, In theory, char can use less space if the amount of space needed is known. This isn't a good reason to use char though; just wanted to mention it.
In practice, it is useful to use char if you care exactly how long a field should be. For example, suppose I am storing a US social security number. It had better be exactly 9 characters. If not, it is meaningless. Here, char(9) has business meaning and the database helps enforce it. If someone accidentally adds an 8 character String, the database insert will fail - warning them of a data integrity problem.