My favorite SQL tutorial: http://sqlzoo.net/
Do your field names need to be globally unique: yes and no. Some design
philosophies require that every field on every table be uniquely
identified. The only uniqueness requirement you must obey is that no two
fields on the same table can have the same name. What you call your fields
should reflect the data that's in them and not be too much of a hassle to
type (not strangely punctuated)
For me, I personally do not use tablename_fieldname to name my fields.
This disagrees with several style doctrines but it works for me.
When you join two tables that share field names, both fields will appear
in the result (named identically)., Your naming pattern would avoid that
except in the case of self-joins (one table that joins to itself). The
other way to avoid duplicate field names in your output is to use the
"alias" feature of SQL.
Let's say you have a table of employees. Each employee gets an ID value,
has a name, a department, and a boss (identified by it's id value). One
way to buld this table would look like
CREATE TABLE employee {
id int auto_increment
, boss_employee_id int
, department varchar(16)
, lastname varchar(32)
, firstname varchar(32)
, PRIMARY KEY(id)
, UNIQUE(firstname, lastname)
}
(using my preferred naming pattern)
I used "boss_employee_id" instead of "boss_id" because I wanted to
indicate both what the field contained and where the data came from. Most
of my fields with _ in their names point to data in other tables, some
just looked better with the spacer.
If you have tried the tutorial and are still lost, let us know and someone
will happily work with you.
Shawn Green
Database Administrator
Unimin Corporation - Spruce Pine
Rich <[EMAIL PROTECTED]> wrote on 10/04/2005 12:43:17 PM:
> Hi folks. Any chance on a tutorial from joins? I find them totally
> confusing and I know there's some power in them, so I need to learn
them.
>
> Having asked that, another question arises...do my field names in
different
> tables within the same database have to overlap (same field name) in
order
> for joins to work? I'm currently naming fields in such a manner:
>
> TABLE1
> table1_alpha
> table1_bravo
>
> TABLE2
> table2_firstname
> table2_lastname
>
> Appreciate any guidance on these two questions.
>
> Cheers
>
>
>
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