Foreign key on table A --> B, AND foreign key on table B --> A. How is this done?

Posted by unclaimedbaggage on Stack Overflow See other posts from Stack Overflow or by unclaimedbaggage
Published on 2010-05-21T10:29:35Z Indexed on 2010/05/21 10:40 UTC
Read the original article Hit count: 221

Filed under:

db

|

schema

|

mysql

Hi,

I have two tables - 'business' and 'business_contacts'.

The business_contact table has a many-to-one relationship with the business table. Furthermore, each business has a 'primary contact' field - which I'd assume is a one-to-many relationship with the business_contacts table.

The problem, of course, is that this creates a catch-22 for data insertion. Since neither field can be null, I can't insert a business_contact until I have a corresponding business, but I can't insert a business until I have a corresponding business_contact.

If anyone could help me get my head around how mutual one-to-many relationships are supposed to be dealt with I'd be most appreciative.

(Project being done in MySQL if it makes any difference)

© Stack Overflow or respective owner

Related posts about db

OTN ???? ?????? ???????

as seen on Oracle Blogs - Search for 'Oracle Blogs'
Database ?? Database ??????? Database ?????????? Java WebLogic Server/????????·???? SOA/BPM/????? ???????/???? ID??/?????? ?????EPM/BI EPM/BI ??????? EPM/BI ???? OS/??? ???? ????? MySQL Database ?? ???? ?? ????????? ??? ?? ORACLE MASTER… >>> More
Choosing between Berkeley DB Core and Berkeley DB JE

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm designing a Java based web-app and I need a key-value store. Berkeley DB seems fitting enough for me, but there appears to be TWO Berkeley DBs to choose from: Berkeley DB Core which is implemented in C, and Berkeley DB Java Edition which is implemented in pure Java. The question is, how to choose… >>> More
Is it better to create the db/tables programmatically or through a .db file in assets

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, does Android have a "best practices" guideline on creating & populating the db/tables programmatically vs. deploying a .db file in assets? What are the pros/cons of both approaches? I have a db with big long strings in several columns, and about 50 rows, so writing the insert statements… >>> More
Where is meta.local_fields set in django.db.models.base.py ?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm getting the error: Exception Value: (1110, "Column 'about' specified twice") As I was reviewing the Django error page, I noticed that the customizations the model User, seem to be appended to the List twice. This seems to be happening here in django/db/model/base.py in base_save(): values… >>> More
Why do two patterns (/.*) and (.*) match different strings? @per-directory (.htaccess) mod_rewrite RewriteRule

as seen on Server Fault - Search for 'Server Fault'
Shouldn't the two patterns (/.*) and (.*) match the same string? My real question is actually: where did the "abc" go? Something funky seems to be happening inside the mod_rewrite engine... Given this .htaccess file in www/dir/: Options +FollowSymlinks RewriteEngine on RewriteRule (/.*) print_url_args… >>> More

Related posts about schema

Active Directory and Apple's Workgroup Manager

as seen on Server Fault - Search for 'Server Fault'
I thought I'd share my experiences here. I work for a small business with only ~20 users. I wanted the ability to use managed client preferences to assign things like the software update server. Basically the ability to manage my Macs easily and in a native way. At first I tried the magic triangle… >>> More
SQL SERVER – How to Compare the Schema of Two Databases with Schema Compare

as seen on SQL Authority - Search for 'SQL Authority'
Earlier I wrote about An Efficiency Tool to Compare and Synchronize SQL Server Databases and it was very much well received. Since the blog post I have received quite a many question that just like data how we can also compare schema and synchronize it. If you think about comparing the schema manually… >>> More
Copy a domain in old schema to new schema with a procedure in postgresql

as seen on Stack Overflow - Search for 'Stack Overflow'
How do we copy a domain in old schema to new schema using a procedure in postgresql? >>> More
Star Schema vs Snowflake Schema performance

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi... I'm begin to developing a scial sharing website so I'm curious about database design Schema... So in Data-Mining Star-Schema is the best one but how about a social sharing website... And as a nature of the SS websites there will be (i hope :)) many users in same time... Which better for performance… >>> More
java.lang.NoClassDefFoundError: org/springframework/transaction/interceptor/TransactionInterceptor

as seen on Stack Overflow - Search for 'Stack Overflow'
I am trying to integrate spring 3.1.1 with hibernate 4.0. This is my dispatcher-servlet.xml: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www… >>> More