Why does VARCHAR need length specification? Why does VARCHAR need length specification? database database

Why does VARCHAR need length specification?


sql database varchar

The "length" of the VARCHAR is not the length of the contents, it is the maximum length of the contents.

The max length of a VARCHAR is not dynamic, it is fixed and therefore has to be specified.

If you don't want to define a maximum size for it then use VARCHAR(MAX).

sql database varchar

First off, it does not needed it in all databases. Look at SQL Server, where it is optional.

Regardless, it defines a maximum size for the content of the field. Not a bad thing in itself, and it conveys meaning (for example - phone numbers, where you do not want international numbers in the field).

sql database varchar

You can see it as a constraint on your data. It ensures that you don't store data that violates your constraint. It is conceptionally similar to e.g. a check constraint on a integer column that ensure that only positive values are entered.

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