Question

When I’m creating instances of domain objects from a ResultSet, should I convert Strings which are null to an empty String. Conversely, when writing to the database should empty Strings be converted to null Strings?

What’s best practise here? Or is it just dependent on the application?

Many thanks.

Answer 1

The empty string, "" is a string just as any other. To me it, storing "" as NULL makes as much sense as storing "" as '' and storing "abc" as NULL.

So, keep things simple: Store "" as '', and store a null reference as NULL.

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To quote the MySQL reference manual:

The concept of the NULL value is a common source of confusion for newcomers to SQL, who often think that NULL is the same thing as an empty string ''.