报错
Caused by: java.sql.SQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (myshop.tb_product_img, CONSTRAINT fk_proimg_product FOREIGN KEY (product_id) REFERENCES tb_product (product_id))

tb_product_img的myaql代码

CREATE TABLE tb_product_img(
product_img_id int(20) NOT NULL auto_increment,
img_addr VARCHAR(2000) NOT NULL,
img_desc VARCHAR(2000) DEFAULT NULL,
priority int(2) DEFAULT ‘0’,
create_time datetime DEFAULT NULL,
product_id int(20)DEFAULT NULL,
PRIMARY KEY(product_img_id),
constraint fk_proimg_product foreign key(product_id) references tb_product(product_id)
)ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

tb_product代码
CREATE TABLE tb_product(
product_id int(100) NOT NULL auto_increment,
product_name varchar(100) NOT NULL,
product_desc VARCHAR(2000) DEFAULT NULL,
img_addr varchar(2000) default ‘’,
normal_price varchar(100) default null,
promotion_price varchar(100) default null,
priority int(2) not null default’0’,
create_time datetime DEFAULT NULL,
last_edit_time datetime DEFAULT null,
enable_status int(2) NOT NULL DEFAULT’0’,
product_category_id int(11) default null,
shop_id int(20) not null default’0’,
PRIMARY KEY(product_id),
constraint fk_product_shop foreign key(shop_id) references tb_shop(shop_id),
constraint fk_product_procate foreign key(product_category_id) references
tb_product_category(product_category_id)
)ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

我感觉没有错啊 可是就是找不出原因，麻烦老师帮忙看看