I have 3 tables: users, photos, avatars (photo of user_1 that currently see user_2) when user deleted, all his photos and avatars, that shown to other users also removes What I do wrong?
cursor.execute("""CREATE TABLE IF NOT EXISTS users(
id int AUTO_INCREMENT PRIMARY KEY,
user_id INTEGER NOT NULL UNIQUE,
goal VARCHAR(255) DEFAULT NULL,
gender VARCHAR(255) DEFAULT NULL,
dob DATE DEFAULT NULL,
country VARCHAR(255) DEFAULT NULL,
city VARCHAR(255) DEFAULT NULL)""")
cursor.execute("""CREATE TABLE IF NOT EXISTS photos(
id INTEGER AUTO_INCREMENT,
user_id INTEGER NOT NULL,
photo VARCHAR(255) NOT NULL,
KEY (id),
PRIMARY KEY (user_id, photo),
FOREIGN KEY (user_id) REFERENCES users (user_id) ON DELETE CASCADE)""")
cursor.execute("""CREATE TABLE IF NOT EXISTS avatars (
id INTEGER AUTO_INCREMENT PRIMARY KEY,
user_id INTEGER,
avatar VARCHAR(255),
shower_id INTEGER,
FOREIGN KEY (user_id) REFERENCES users (user_id) ON DELETE CASCADE,
FOREIGN KEY (avatar) REFERENCES photos (photo) ON DELETE CASCADE,
FOREIGN KEY (shower_id) REFERENCES users (user_id) ON DELETE CASCADE)""")
But I get an error
1822, "Failed to add the foreign key constraint. Missing index for constraint 'avatars_ibfk_2' in the referenced table 'photos'")
mysqlsh.exe --version
C:\Program Files\MySQL\MySQL Shell 8.0\bin\mysqlsh.exe Ver 8.0.19 for Win64 on x86_64 - for MySQL 8.0.19 (MySQL Community Server (GPL))