查看商品表中已创建的触发器。
时间: 2023-09-04 17:11:52 浏览: 35
您可以使用以下 T-SQL 语句查看商品表中已创建的触发器:
```
SELECT name
FROM sys.triggers
WHERE parent_class = 1 AND parent_id = OBJECT_ID('dbo.商品表')
```
其中,`sys.triggers` 是 SQL Server 系统视图,用于显示数据库中已创建的触发器的信息。`parent_class` 和 `parent_id` 分别指示触发器所属对象的类型和 ID,`1` 表示表对象,`dbo.商品表` 是您要查询的表名。如果您的表位于不同的模式中,请相应地调整表名。
相关问题
1.创建触发器tr1,实现当修改商品表中的数据时,显示提示信息“商品表信息被修改了。” 2.使用触发器tr2,实现当修改商品表中某种商品的商品编号时,对应购买信息表中的商品编号也要修改。 3.创建一个DDL触发器tr3,禁止修改和删除当前数据库中的任何表。 4.查看商品表中已创建的触发器。 5.查看已创建的触发器tr1的内容。 6.删除商品表上的触发器tr1。
以下是针对题目的触发器创建和修改的代码:
1. 创建触发器tr1
```sql
CREATE TRIGGER tr1
ON 商品表
AFTER UPDATE
AS
BEGIN
PRINT '商品表信息被修改了。'
END;
```
2. 创建触发器tr2
```sql
CREATE TRIGGER tr2
ON 商品表
AFTER UPDATE
AS
BEGIN
IF UPDATE(商品编号)
BEGIN
UPDATE 购买信息表 SET 商品编号 = inserted.商品编号 FROM 购买信息表 JOIN inserted ON 购买信息表.商品编号 = deleted.商品编号;
END;
END;
```
3. 创建DDL触发器tr3
```sql
CREATE TRIGGER tr3
ON DATABASE
FOR ALTER_TABLE, DROP_TABLE
AS
BEGIN
PRINT '当前数据库中的任何表不允许修改和删除。';
ROLLBACK;
END;
```
4. 查看商品表中已创建的触发器
```sql
SELECT * FROM sys.triggers WHERE parent_object_id = OBJECT_ID('商品表');
```
5. 查看已创建的触发器tr1的内容
```sql
sp_helptext tr1;
```
6. 删除商品表上的触发器tr1
```sql
DROP TRIGGER tr1 ON 商品表;
```
用Java语句创建三个表,订单表,商品表,用户表和管理员表,并创建触发器
好的,以下是用Java语句创建四个表的示例代码:
```java
import java.sql.*;
public class CreateTablesWithTriggers {
public static void main(String[] args) {
String url = "jdbc:mysql://localhost:3306/mydatabase";
String username = "root";
String password = "password";
try (Connection conn = DriverManager.getConnection(url, username, password);
Statement stmt = conn.createStatement()) {
// 创建用户表
String createUserTable = "CREATE TABLE users (" +
"id INT NOT NULL AUTO_INCREMENT," +
"username VARCHAR(50) NOT NULL," +
"password VARCHAR(50) NOT NULL," +
"PRIMARY KEY (id)" +
")";
stmt.executeUpdate(createUserTable);
// 创建商品表
String createProductTable = "CREATE TABLE products (" +
"id INT NOT NULL AUTO_INCREMENT," +
"name VARCHAR(50) NOT NULL," +
"price DECIMAL(10, 2) NOT NULL," +
"description VARCHAR(100)," +
"PRIMARY KEY (id)" +
")";
stmt.executeUpdate(createProductTable);
// 创建订单表
String createOrderTable = "CREATE TABLE orders (" +
"id INT NOT NULL AUTO_INCREMENT," +
"user_id INT NOT NULL," +
"product_id INT NOT NULL," +
"quantity INT NOT NULL," +
"total DECIMAL(10, 2) NOT NULL," +
"timestamp TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP," +
"PRIMARY KEY (id)," +
"FOREIGN KEY (user_id) REFERENCES users(id)," +
"FOREIGN KEY (product_id) REFERENCES products(id)" +
")";
stmt.executeUpdate(createOrderTable);
// 创建管理员表
String createAdminTable = "CREATE TABLE admins (" +
"id INT NOT NULL AUTO_INCREMENT," +
"username VARCHAR(50) NOT NULL," +
"password VARCHAR(50) NOT NULL," +
"PRIMARY KEY (id)" +
")";
stmt.executeUpdate(createAdminTable);
// 创建订单触发器,自动更新商品表中的库存数量
String createOrderTrigger = "CREATE TRIGGER update_inventory " +
"AFTER INSERT ON orders " +
"FOR EACH ROW " +
"BEGIN " +
"UPDATE products SET inventory = inventory - NEW.quantity " +
"WHERE id = NEW.product_id; " +
"END";
stmt.executeUpdate(createOrderTrigger);
System.out.println("Tables and triggers created successfully.");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
```
注意:以上代码仅为示例,实际应用中需要根据具体业务需求进行修改。