Solved

FK relationship in MySQL in WorkBench IDE

Posted on 2010-08-12
4
654 Views
Last Modified: 2013-11-08
i'm having trouble creating a one to many foreign key relationship between two InnoDB tables that I have created in my MySQL db using the workbench IDE. I'm using this in conjuction with vs 2010 and the entity framework. so i'm looking for some visual aids (tutorials preferably) that address this and show me the proper way to achieve this. Any suggestions and or suggested resources would be appreciated.
0
Comment
Question by:mikesExpertExchange
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
4 Comments
 
LVL 42

Accepted Solution

by:
dqmq earned 500 total points
ID: 33424308
You implement a one-many relationship simply by including a key of the parent table (the one) in the child table (the many).  Usually, it is the primary key, but any unique key will do.

If you want the database to enforce the integrity of that relationship, then you use a foreign key constraint.  The foreign key constraint is a "rule" applied to the child table that guarantees the value of the foreign key will be present in the referenced unique key of the parent table.

alter table CHILDTABLE add constraint CONSTRAINTNAME foreign key (COL1, COL2...) references PARENTTABLE (COL1, COL2)

I haven't used MySQL IDE, but most development enviornments provide a graphical way to create the necessary keys and constraints.  Someone else will need to assist you with that.  
0
 
LVL 1

Author Comment

by:mikesExpertExchange
ID: 33425010
thank you. as a sidenote, good, bad or indifferent, can you have a primary key that is a character string?
0
 
LVL 42

Expert Comment

by:dqmq
ID: 33432608
Absolutely!  But if it's longer than 16 bytes, I'd reconsider (for optimization reasons).
0
 
LVL 1

Author Comment

by:mikesExpertExchange
ID: 33432781
thanks for your help....
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
remote mysql 8 40
CSS for Popup in ASP.NET 4 19
Broken .resx file generating errors 18 25
Set arraylist as datatable 2 11
Popularity Can Be Measured Sometimes we deal with questions of popularity, and we need a way to collect opinions from our clients.  This article shows a simple teaching example of how we might elect a favorite color by letting our clients vote for …
More often than not, we developers are confronted with a need: a need to make some kind of magic happen via code. Whether it is for a client, for the boss, or for our own personal projects, the need must be satisfied. Most of the time, the Framework…
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…
How to Install VMware Tools in Red Hat Enterprise Linux 6.4 (RHEL 6.4) Step-by-Step Tutorial

726 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question