如何在Oracle 10g数据库中连接两个表？

Question

I have table named REGISTRATION with fields like ID, NAME, PASSWORD, USERNAME . I want to make another table named PHOTOS with fields ID, TITLE, PHOTO . The thing I want to ask is that I want the ID field of the PHOTOS table should match with the ID field of the REGISTRATION table. Whenever there is any entry in the REGISTRATION table the content of ID field gets copied into the ID field of PHOTOS table....??

Answer 1

If you have only one photo per user, then yes, it is a good idea to make ID the same. But then why it is not just one table that contains info from registration and photos?

if you have multiply photos per user, then no. ID usually recognized as unique identifier of a record in a table (2 records in the same table have different IDs). So instead of using ID for user, you use UserId as an additional column in PHOTOS table.