在PHP / MySQL中更新关系数据库

Question

I am teaching myself about web programming. I am trying to create a user account for a website. I have two databases - first one (db_users - userid (auto increment), username, password) to store user information like the username, password, etc. and second one (db_address - userid (auto increment), address1, address2, city) to store the user's address.

Now when I register a user, how do I ensure that both the tables are updated with the correct user id? Or is that not how a relational database works?

Answer 1

A user data is not the case for the relational database.
There is no point in having 2 tables for the user (as well as having 2 fields for the address).

Make it one table, then add comments table and have user id field in it.
Thus you will have a real case of the relational database.

Answer 2

Without going into code you want to do:

1. Insert details into user table
2. Get ID inserted using $id = mysql_insert_id()
3. Insert details into address table using $id

EDIT: If using more than one MySQL connection you need to do $id = mysql_insert_id($connection)

Answer 3

First of all, I think you probably have two tables, not two databases. Second, your address table should have an addressid column, which you should auto-increment. You are responsible yourself for setting the proper userid in the address table. This way you can have multiple addresses per account. For example, 1 for delivery and 1 for billing.

Btw, if you only plan to have 1 address per user you could consider merging the two tables and adding the address information to the account table. Formally, this would go against normalization rules, but in this case it would probably be more practical.

Answer 4

Userid should not be the auto incremented index in the second table. Separating user and address data means a user could be connected to more than 1 address, and multiple users could have same address (living together, in other words). Or you could merge the tables, if it suits you.

db_users:

• userid (auto increment)
• username
• password

db_address:

• address_id (auto increment)
• userid
• address1
• address2
• city