I am very new in database design and merely explore the field of relational database. Just look at this article http://net.tutsplus.com/tutorials/databases/sql-for-beginners-part-3-database-relationships/ It is a nice reading through however i just can barely touch the floor.
What still confusing me is exactly what the gap between someone to many and several to 1 relationship? It is simply the 'vice-versa' type of?
Very appreciate if a person can explain the main difference in a nutshell and sweet answer or you can provide a number of good find out about this subject? (I have google many occasions however i aren't able to find any 'good-and-easy-to-understand' tutorial relating to this subject.)
Thank you for help!
Most relations between tables are one-to-many.
* One area can be the habitat of many readers. * One reader can have many subscriptions. * One newspaper can have many subscriptions.
A Many to 1 relation is equivalent to one-to-many, but from the different point of view.
* Many readers live in one area. * Many subscriptions can be of one and the same reader. * Many subscriptions are for one and the same newspaper.
Yes, it smoking versa. It is dependent which side from the relationship the entity exists on.
For instance, if a person department can employ for many employees then, department to worker is a to a lot of (1 department utilizes many employees), while worker to department relationship is many to 1 (many employees operate in one department).
More information around the relationship types: Database Relationships - IBM DB2 docuemntation
There's no difference. It's only a matter of language and preference regarding which way round you condition the connection.