ERD-generation: boolean -> number(1)? (Oracle)

General Questions/Discussions
1

Why the “boolean” type in ClassDiagram generated as “number(1)” in ERD? I use Oracle as default database.
TIA, Eugeny

2

Hi vinger4,

I’m not a moderator or VP’s staff, but I guess I can share my opinion on your question. There’s no ‘boolean’ native type in Oracle as-is. It’s up to the implementor how that type will be represented; a number that can be 0 for false and anything >0 positive it’s one way, which I guess that’s how DBVA is doing it. Another way is using a CHAR(1) with a ‘Y’ or ‘N’ as the values; some people will use any type and NULL as well, but beware of the last form, you can easily say that anything that is not true is false, and NULL is definitely not true, but the idea of NULL is to represent absence of data or simply, data that is undefined. But a column always has a type.

Hope that helps,

3

Thanks!
I hope that I can change “boolean->number(1)” to “boolean->char(1)” in next realise, because we usually use char(1) as boolean type in Oracle.