详解SQL四种语言：DDL DML DCL TCL

CREATE DATABASE test; // 创建一个名为test的数据库

ALTER TABLE test ADD birthday date; // 修改test表，新增date类型的birthday列

DROP DATABASE test;// 删除test数据库

SET NAMES utf8;
SET FOREIGN_KEY_CHECKS = 0;
 
-- ----------------------------
-- Table structure for `city`
-- ----------------------------
DROP TABLE IF EXISTS `city`;
CREATE TABLE `city` (
 `id` int(11) NOT NULL DEFAULT '0' COMMENT '城市ID',
 `name` varchar(20) DEFAULT NULL COMMENT '名称',
 `state` varchar(20) DEFAULT NULL COMMENT '状态',
 `country` varchar(20) DEFAULT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
 
SET FOREIGN_KEY_CHECKS = 1;

/
  描述:JDBC数据库事务回滚
 
  Created by bysocket on 16/6/6.
 /
public class TransactionRollBack extends BaseJDBC {
 
  public static void main(String[] args) throws SQLException {
    Connection conn = null;
    try {
      // 加载数据库驱动
      Class.forName(DRIVER);
      // 数据库连接
      conn = DriverManager.getConnection(URL,USER,PWD);
 
      // 关闭自动提交的事务机制
      conn.setAutoCommit(false);
      // 设置事务隔离级别 SERIALIZABLE
      conn.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE);
 
      Statement stmt = conn.createStatement();
      int rows = stmt.executeUpdate("INSERT INTO city VALUES (3,'china',1,'')");
      rows = stmt.executeUpdate("UPDATE city set country = 'TAIWAN' WHERE id = 4");
 
      // 提交事务
      conn.mit();
    } catch (Exception e) {
      e.printStackTrace();
      // 回滚事务
      if (conn != null) {
        conn.rollback();
      }
    } finally {
      / 关闭数据库连接 /
      if (conn != null) {
        try {
          conn.close();
        } catch (SQLException e) {
          e.printStackTrace();
        }
      }
    }
  }
}

/
  描述:JDBC数据库事务回滚,回滚到特定的保存点
 
  Created by bysocket on 16/6/6.
 /
public class TransactionRollBack2 extends BaseJDBC {
  public static void main(String[] args) throws SQLException {
    Connection conn = null;
    Savepoint svpt = null;
    try {
      // 加载数据库驱动
      Class.forName(DRIVER);
      // 数据库连接
      conn = DriverManager.getConnection(URL,USER,PWD);
 
      // 关闭自动提交的事务机制
      conn.setAutoCommit(false);
      // 设置事务隔离级别 SERIALIZABLE
      conn.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE);
 
      Statement stmt = conn.createStatement();
      int rows = stmt.executeUpdate("INSERT INTO city VALUES (3,'china',1,'')");
      // 设置事务保存点
      svpt = conn.setSavepoint();
      rows = stmt.executeUpdate("UPDATE city set country = 'TAIWAN' WHERE id = 4");
 
      // 提交事务
      conn.mit();
    } catch (Exception e) {
      e.printStackTrace();
      // 回滚事务
      if (conn != null) {
        conn.rollback(svpt);
      }
    } finally {
      / 关闭数据库连接 /
      if (conn != null) {
        try {
          conn.close();
        } catch (SQLException e) {
          e.printStackTrace();
        }
      }
    }
  }
}