Your data model is flawed.
Put it all in one table instead and add a column for the
Item_type
.
Now you can simply join the tables on
Item_type
.
The wiki article on normalization is
here[
^].
But a better article on the why is
here[
^], and Celko is a proper authority on the subject, he's been on the committee writing the SQL standard.
And then I'd also recommend
this[
^] article. It's having the benefit of explaining how in plain English being void of buzzwords.