PHP and MySQL to populate table from unknown ID

Question

I have three tables: unitpost, file, and postfile with postfile being the table that links files to a particular post.

I have created a script that uploads the files and posts however I need to populate the postfile table with both the unitpostID and fileID, however once the file is uploaded, the ID is chosen at random. How can I then populate the postfile table with the fileID that was just uploaded?

Hope this made sense!!

Any help appreciated.

Answer 1

使用LAST_INSERT_ID()获取上一次插入操作的ID。

Answer 2

Use AUTOINCREMENT for the primary keys, thus the IDs won't be random, and you will be able to use them either from MySQL or from PHP.

Afterwards use mysqli_insert_id() (or PDO::lastInsertId if you use PDO) from php to get the last insert id, or, as @Nelson stated, the MySQL function directly.