Linking tables

[mds1256]

Hi

 

Just working on a bit database design and have the following scenario:

 

 

users Table = Contains ID, username and password

 

personDetails Table = contains ID, userid, first name, surname, DoB

 

 

Now when linking the table e.g. to return First and Surname for a specific username is it better to have a linking table as well, so for example (pseudo speak)

 

Select firstname, surname from personDetails, users where personDetails.userid = users.id

 

Or have another linking table and that to contain:

 

id

userID

personDetailsID

 

and use this to link, or does it not matter which way you link?

 

 

[shlumph]

There's no need for a third relational table. Unless a user has many personDetails... which probably doesn't make much sense.

 

Also, if every user has a userid, firstname, surname, DoB, username, and password, then I'd put them into one table.

[mds1256]

thanks for the info, now got my head around why and when you would use a linking table

 

 

for your second comment, what is gained from putting them in one table? just thought it would be better to seperate data out like that?

[shlumph]

There's no real need to have them in a separate table since there is a one to one relation, and the fields will *always* be filled. If some users didn't have a first name, surname, & DoB then it'd be much better to create that second table.

 

I'm not saying it's wrong and won't work the way you have it, though

[mds1256]

Thanks, understand what you mean

 

Im just learning this stuff so advice is welcoming