此结构中的表
customersaccountstransactionscardsloans
表结构（SQL）
MySQL 方言的 DDL。在编辑器中打开可获得可编辑的可视化 ER 图，或直接将 SQL 复制到你的项目中。
CREATE TABLE customers (
id INT PRIMARY KEY AUTO_INCREMENT,
full_name VARCHAR(120) NOT NULL,
email VARCHAR(254) NOT NULL UNIQUE,
phone VARCHAR(32),
created_at DATETIME NOT NULL
);
CREATE TABLE accounts (
id INT PRIMARY KEY AUTO_INCREMENT,
customer_id INT NOT NULL,
account_number VARCHAR(34) NOT NULL UNIQUE,
type VARCHAR(20) NOT NULL,
balance DECIMAL(16,2) NOT NULL DEFAULT 0,
currency VARCHAR(3) NOT NULL,
opened_at DATETIME NOT NULL,
FOREIGN KEY (customer_id) REFERENCES customers(id)
);
CREATE TABLE transactions (
id BIGINT PRIMARY KEY AUTO_INCREMENT,
account_id INT NOT NULL,
amount DECIMAL(16,2) NOT NULL,
direction VARCHAR(6) NOT NULL,
description VARCHAR(200),
created_at DATETIME NOT NULL,
FOREIGN KEY (account_id) REFERENCES accounts(id)
);
CREATE TABLE cards (
id INT PRIMARY KEY AUTO_INCREMENT,
account_id INT NOT NULL,
card_number VARCHAR(19) NOT NULL UNIQUE,
type VARCHAR(20) NOT NULL,
expires_on DATE NOT NULL,
status VARCHAR(20) NOT NULL,
FOREIGN KEY (account_id) REFERENCES accounts(id)
);
CREATE TABLE loans (
id INT PRIMARY KEY AUTO_INCREMENT,
customer_id INT NOT NULL,
principal DECIMAL(16,2) NOT NULL,
interest_rate DECIMAL(5,2) NOT NULL,
term_months INT NOT NULL,
status VARCHAR(20) NOT NULL,
opened_at DATE NOT NULL,
FOREIGN KEY (customer_id) REFERENCES customers(id)
);