?
Solved

FK relationship in MySQL in WorkBench IDE

Posted on 2010-08-12
4
Medium Priority
?
656 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:Michael Sterling
[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 2000 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:Michael Sterling
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:Michael Sterling
ID: 33432781
thanks for your help....
0

Featured Post

Get proactive database performance tuning online

At Percona’s web store you can order full Percona Database Performance Audit in minutes. Find out the health of your database, and how to improve it. Pay online with a credit card. Improve your database performance now!

Question has a verified solution.

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

Password hashing is better than message digests or encryption, and you should be using it instead of message digests or encryption.  Find out why and how in this article, which supplements the original article on PHP Client Registration, Login, Logo…
In this blog post, we’ll look at how ClickHouse performs in a general analytical workload using the star schema benchmark test.
In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment. To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…
In this video, Percona Solutions Engineer Barrett Chambers discusses some of the basic syntax differences between MySQL and MongoDB. To learn more check out our webinar on MongoDB administration for MySQL DBA: https://www.percona.com/resources/we…
Suggested Courses

752 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