The Worst Database Design

Let’s create tables… like this:

CREATE TABLE A
(
    ID PRIMARY KEY
    ...
);

CREATE TABLE B
(
    ID PRIMARY KEY
    ...
);

The whole idea is that (due to some reasons that I don’t remember) there is one-to-one relation between those two tables (A.id = B.id). One-to-one relation is not quite normal and should be avoided (avoided means don’t do that unless you know what you’re doing). The first table looked like this:
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