MySQL - Update a record and maintain referential integrity - php

Question

I'm working in MySQL 5.5.
I've got a Contacts table like this
CREATE TABLE Contacts
(
ID INTEGER NOT NULL UNIQUE PRIMARY KEY AUTO_INCREMENT,
Name VARCHAR(255) NOT NULL,
Institution VARCHAR(255),
Address VARCHAR(255),
Email VARCHAR(255) NOT NULL UNIQUE,
Phone VARCHAR(10)
);
and an Inventories tables like this
CREATE TABLE Inventories
(
ID INTEGER NOT NULL UNIQUE PRIMARY KEY AUTO_INCREMENT,
InventoryParametersID INTEGER NOT NULL UNIQUE,
ContactID INTEGER NOT NULL,
LocationID INTEGER NOT NULL,
Year INTEGER,
DateUploaded TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
Comments VARCHAR(255),
FOREIGN KEY (ContactID) REFERENCES Contacts(ID)
);
In my webform, contacts upload inventories. Here's the behavior I want:
- When a new contact uploads an inventory, do an insert with their new info
- When an existing contact (determined by email address) uploads another inventory, update their info AND retain referential integrity with the Inventories table
How do I do this?
Here's what I've tried:
CASE
FOREIGN KEY (ContactID) REFERENCES Contacts(ID)
REPLACE INTO Contacts (`Name`, `Institution`, `Address`, `Email`, `Phone`) VALUES (?, ?, ?, ?, ?);
RESULT
No change
CASE
FOREIGN KEY (ContactID) REFERENCES Contacts(ID)
ON UPDATE CASCADE
REPLACE INTO Contacts (`Name`, `Institution`, `Address`, `Email`, `Phone`) VALUES (?, ?, ?, ?, ?);
RESULT
No change

Answer 1

A REPLACE deletes find row and add a new. So your ON UPDATE CASCADE doesn't work. Why do you not use an INSERT ... ON DUPLICATE KEY UPDATE?
INSERT INTO Contacts (Name, Institution, Address, Email, Phone)
VALUES (?, ?, ?, ?, ?) ON DUPLICATE KEY UPDATE
Name = VALUES(NAME),
Institution = VALUES(Institution) ...
MySQL DOC