mysql - 为什么会出现这个错误 "#1215 - Cannot add foreign key constraint "？

Question

CREATE TABLE postcodes (
    postcode_ID INT NOT NULL,
    location VARCHAR(50),
    PRIMARY KEY (postcode_ID)
);

CREATE TABLE countries (
    country_ID INT NOT NULL AUTO_INCREMENT,
    country_name VARCHAR(50),
    PRIMARY KEY (country_ID)
);

CREATE TABLE suppliers (
    supplier_ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    supplier_name VARCHAR(50), 
    supplier_forename VARCHAR(50),
    supplier_phonenumber VARCHAR(20),
    supplier_address VARCHAR(50), 
    supplier_postcode INT,
    supplier_country INT,
    FOREIGN KEY (supplier_postcode) REFERENCES postcode(postcode_ID), 
    FOREIGN KEY (supplier_country) REFERENCES countries(country_ID)
) ;

Answer 1

错别字:

CREATE TABLE postcodes (
                     ^----plural

    FOREIGN KEY (supplier_postcode) REFERENCES postcode(postcode_ID), 
                                                       ^----no S, singular

您正在尝试引用一个不存在的表。