Re: becoming unconfused

[trogers]

I appreciate this and I have read it several times, the problem is it 
ain't easy to find a practical example, one with real data.  That would 
I could figure out what "symbol" was.  In fact what I am doing now is 
trying to build a small DB so I can learn these things --the books and 
I've got lots of them, just don't make it easy to find practical info.  
Name the book and I probably have it.  But they don't show me how to 
get the data in there --from PK of one table to FK of another.  This is 
a close as I've come:
[CONSTRAINT symbol] FOREIGN KEY (studentID)
                  REFERENCES table2 (studentID)
                  [ON DELETE {CASCADE | SET NULL | NO ACTION
                              | RESTRICT}]
                  [ON UPDATE {CASCADE | SET NULL | NO ACTION
                              | RESTRICT}]

But I don't find [quickly] what, say, "symbol" is.  I searched the 
manual for "Constraint symbol" and got the same page I was looking at.

:-(

Ted

On Sunday, June 1, 2003, at 10:11 PM, Becoming Digital wrote:

Check out the InnoDB reference in the MySQL manual.
http://www.mysql.com/doc/en/InnoDB.html
Here's the section Foreign Key Constraints
http://www.mysql.com/doc/en/InnoDB_foreign_key_constraints.html
Good luck.

Edward Dudlik
Becoming Digital
www.becomingdigital.com
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, 01 June, 2003 21:48
Subject: Re: becoming unconfused
I just came from the bookstore where I perused "Mastering MySQL 4".
Specifically, I wanted to know how to specify a Foreign Key.  After a
thorough, albeit short lived search, and reading every page the index
on "Foreign Key" pointed to, I deduced that all one needs do is put the
blasted field (primary key from other table) into the "many" (re
:appropriate) table.  That there was no "identifier" like there is a
Primary Key.
Ok, my last puzzlement --for now-- is, let me illustrate:

table1 table2
studentID -->PK      classID -->PK
student_name         class_name
                                   studentID  (foreign key)
Simple (yes I'm slow, yes it's a problem) question:  how does the
studentID field in table2 get populated?
Thanks in Advance,
Ted
On Sunday, June 1, 2003, at 06:32 PM, Becoming Digital wrote:

The way I was taught, in my limited education, was simply to have,
say,
the people_id also appear in table2 as a Foreign Key, that tis would
serve to relate the tables.  Now I've been advised that the way to do
this is NOT like that, but to have a third, linking, table
In my opinion, you've been wrongly advised.  I would follow your
original
instinct and use a one->many relationship for people to machines.
Using a third
table is just going to complicate things and goes against the concepts
of
normalized data.
Edward Dudlik
Becoming Digital
www.becomingdigital.com
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: "Becoming Digital" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Sunday, 01 June, 2003 15:59
Subject: Re: Inserting data?
I'd be glad to share.. you mean what the db is supposed to be?  Ok,
there are 3 tables:
table1 = people, people_id = primary key
table2 = machines, machines_id = primary key
One person can have many machines, one machine can only be assigned to
one person.
The way I was taught, in my limited education, was simply to have, 
say,
the people_id also appear in table2 as a Foreign Key, that tis would
serve to relate the tables.  Now I've been advised that the way to do
this is NOT like that, but to have a third, linking, table where there
are 2 fields: one is the people_id (primary key from table1) and the
other is the machines_id (primary key from table2).

I was asking how to write a SQL statement to populate that third table
from the data already in/from the other 2.
Any other comments about this are welcome.

Thanks,
Ted
On Sunday, June 1, 2003, at 10:53 AM, Becoming Digital wrote:

You need a constraint on the data to be inserted into the second
table.  Care to
share what that is supposed to be?
Edward Dudlik
Becoming Digital
www.becomingdigital.com
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, 01 June, 2003 03:17
Subject: Inserting data?
I have a table, in the table is a field called  name_id; in a second
table (a linking table) I also have the field name_id, this should be
the same/reference the same name_id as in the first table.
The first table is fully populated.  How do write a SQL statement to
get the data from the name_id field of table1 into the name_id field
of
table2?
(I'll do this and find out after if it actually references the same
data!  So, if it doesn't at least I'll have learned the proper SQL
statement. :)
Thank you,
Ted Rogers