如何在 php 中同时从单个表单插入记录时将数据库中表的主键用作表 2 中的外键

Question

I am fairly new to web development and currently working on a website using an MVC framework that can capture maintenance work conducted. I have managed to make the forms and it correctly displays any errors in filling the form and if there aren't any errors successfully inserts it into the database. What I would like to achieve is having the main table with the general details of the maintenance such as (date, time, technician, department, location, recommendations) and another table for which records what tasks were done during the maintenance such as sweeping, mopping, wiping the windows, cutting grass, etc. I have a single form that requires all the details required in both the tables to be filled. both tables will have primary keys that will be auto-increment. I would then like to simultaneously insert the data into the relevant tables only while inserting data into the tasks table I would like to have a foreign key to the main table for that particular record so it corresponds accordingly. How can I achieve this without manual input by the user if the primary key of the main table is an auto increment?

Answer 1

This isn't a big problem. It can't be done as a single query, but using transactions you can achieve an all-or-nothing result.

In pseudocode:

• Validate data
• Start a transaction
• Insert data into main record
• Get the last inserted ID
• Insert one or more records into the child table, using the ID retrieved above
• Commit the transaction (or roll back if some error occurred)

The exact mechanics vary between MySQLi and PDO, but the principle is the same.