JAVA操作数据库-->从一张表中取值，经过判断，然后插入另一张表中。

JAVA操作数据库-->从一张表中取值，经过判断，然后插入另一张表中。

SQL语句如下：两张表 weather 和 weather_process.

id均为自动增长。Oracle中采用序列 Sequence

写的不对的地方，欢迎大家指出。您的建议，也是我的进步。谢谢！

DROP SEQUENCE weather_id;

CREATE SEQUENCE weather_id //创建序列

INCREMENT BY 1 //每次增加1

START WITH 1 //从1开始，即id从1开始 每次增1 如：1,2,3...

NOMAXVALUE //不设置最大值

NOCYCLE; //不用循环

插入值的时候，id 字段写成weather_id.nextval 便完成了自动增加的功能！

INSERT INTO WEATHER(id, weather) values (weather_id.nextval,'晴');

DROP TABLE WEATHER;
CREATE TABLE WEATHER (
ID INT PRIMARY KEY NOT NULL,
weather VARCHAR(20) NOT NULL
);
DROP WEATHER_PROCESS;
CREATE TABLE WEATHER_PROCESS(
ID INT PRIMARY KEY NOT NULL,
阴 int NOT NULL default 0,
晴 int NOT NULL default 0,
雨 int NOT NULL default 0
);
DROP SEQUENCE weather_id;
CREATE SEQUENCE weather_id
INCREMENT BY 1
START WITH 1
NOMAXVALUE
NOCYCLE;

DROP SEQUENCE weather_process_id ;
CREATE SEQUENCE weather_process_id
MINVALUE 1
START WITH 1
INCREMENT BY 1;

INSERT INTO WEATHER(id, weather) values (weather_id.nextval,'晴');
INSERT INTO weather(id, weather) values (weather_id.nextval,'雨');
INSERT INTO weather(id, weather) values (weather_id.nextval,'阴');
INSERT INTO weather(id, weather) values (weather_id.nextval,'雨');
INSERT INTO weather(id, weather) values (weather_id.nextval,'阴');
INSERT INTO weather(id, weather) values (weather_id.nextval,'晴');
INSERT INTO weather(id, weather) values (weather_id.nextval,'雨');
INSERT INTO weather(id, weather) values (weather_id.nextval,'晴');

下面来说说这次的主题：根据weather 表中的weather字段 的值（晴，阴，雨），来决定表weather_process 中 阴 晴 雨 的值。

当weather 为 晴时，weather_process 中的值 设置为：0 1 0 （阴，晴，雨）。

当weather 为 阴时，weather_process 中的值 设置为：1 0 0 （阴，晴，雨）。

当weather 为 雨时，weather_process 中的值 设置为：0 0 1 （阴，晴，雨）。

上述采用JAVA 实现。

连接ORACLE 的代码：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
* A JDBC test application for Oracle
*
* @author Wang
* @version 1.0.0
* @since JDK1.6
*/
public class OracleConnect {
// 定义ORACLE的数据库驱动程序
public static final String DBDRIVER = "oracle.jdbc.driver.OracleDriver" ;
// 定义ORACLE数据库的连接地址
public static final String DBURL = "jdbc:oracle:thin:@localhost:1521:ORCL" ;
//ORACLE数据库的连接用户名
public static final String DBUSER = "system" ;
// ORACLE数据库的连接密码
public static final String DBPASS = "www.google.com" ;
public Connection getConnection() {
Connection conn = null ;        // 数据库连接
try {
Class.forName(DBDRIVER) ;
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}   // 加载驱动程序
System.out.println("加载驱动成功！");
try {
conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("连接成功！");
return conn;
}

}

处理表的代码：

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class OracleProcess {
Connection conn = null;
Statement stmt = null;

public  OracleProcess(){
OracleConnect oraconn = new OracleConnect();
conn = oraconn.getConnection();
}
public Connection getWeather() {
try {
stmt = conn.createStatement();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String sql = "SELECT weather FROM WEATHER";
//String sql1 = "CREATE TABLE WEATHER_PROCESS(ID INT PRIMARY KEY NOT NULL,阴 int NOT NULL ,晴 int NOT NULL,雨 int NOT NULL)";
ResultSet result = null;
try {
stmt.executeUpdate(sql);
result = stmt.executeQuery(sql);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
int flag = 0;
while (result.next()) {
//System.out.print(result.getString("weather")+"、");
String str = result.getString("weather");  //获取表中weather的值

if ("阴".equals(str)) {
stmt = conn.createStatement();
/*
*如果不重新stmt一个 则出现的是表中只会插入一条记录，
*然后整个循环就退出了。
*/
String sql2 = "INSERT INTO WEATHER_PROCESS(id, 晴,阴,雨) values (weather_process_id.nextval,0,1,0)";
stmt.executeUpdate(sql2);
System.out.print(str+"、");
}else if ("晴".equals(str)) {
stmt = conn.createStatement();
String sql2 = "INSERT INTO WEATHER_PROCESS(id, 晴,阴,雨) values (weather_process_id.nextval,1,0,0)";
stmt.executeUpdate(sql2);

System.out.print(str+"、");
}else {
stmt = conn.createStatement();
String sql2 = "INSERT INTO WEATHER_PROCESS(id, 晴,阴,雨) values (weather_process_id.nextval,0,0,1)";
stmt.executeUpdate(sql2);
System.out.print(str+"、");
}
flag ++;
}
System.out.println("\n此次一共更新了"+flag+"条语句");

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
result.close();
stmt.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;

}

}

欢迎共同交流，写的不对的地方还望大家谅解，呵呵。
本文出自 “幽灵柯南的技术blog” 博客，转载请与作者联系！