💡 添加 <sql 约束> 示例代码

Zhang Peng · Zhang Peng · commit af9cb2bdacb1 · 2017-08-08T15:00:13.000+08:00
diff --git a/codes/sql/sql_constraint_demo.sql b/codes/sql/sql_constraint_demo.sql
@@ -0,0 +1,68 @@
+/*
+ sql 约束的 Mysql 示例
+ */
+
+-- --------------------------------------------------------------
+-- DDL BEGIN
+-- --------------------------------------------------------------
+
+-- NOT NULL 约束
+DROP TABLE IF EXISTS person;
+CREATE TABLE person (
+    person_id INT NOT NULL,
+    name VARCHAR(255) NOT NULL,
+    age INT,
+    address VARCHAR(255)
+);
+
+-- UNIQUE 约束
+DROP TABLE IF EXISTS person;
+CREATE TABLE person (
+    person_id INT NOT NULL,
+    name VARCHAR(255) NOT NULL,
+    age INT,
+    address VARCHAR(255),
+    UNIQUE (person_id)
+);
+
+-- PRIMARY KEY 约束
+DROP TABLE IF EXISTS person;
+CREATE TABLE person (
+    person_id INT NOT NULL PRIMARY KEY,
+    name VARCHAR(255) NOT NULL,
+    age INT,
+    address VARCHAR(255)
+);
+
+-- FOREIGN KEY 约束
+DROP TABLE IF EXISTS bill;
+CREATE TABLE bill
+(
+	bill_id INT NOT NULL,
+	bill_no INT NOT NULL,
+	person_id INT,
+	PRIMARY KEY (bill_id),
+	FOREIGN KEY (person_id) REFERENCES person(person_id)
+);
+
+-- CHECK 约束
+DROP TABLE IF EXISTS person;
+CREATE TABLE person (
+    person_id INT NOT NULL,
+    name VARCHAR(255) NOT NULL,
+    age INT CHECK (age >= 18),
+    address VARCHAR(255)
+);
+
+-- DEFAULT 约束
+DROP TABLE IF EXISTS person;
+CREATE TABLE person (
+    person_id INT NOT NULL,
+    name VARCHAR(255) NOT NULL,
+    age INT DEFAULT 18,
+    address VARCHAR(255)
+);
+
+-- --------------------------------------------------------------
+-- DDL END
+-- --------------------------------------------------------------
