数据库查询问题？？在线等待回答！！

shujianpiaoling 2003-10-20 09:35:27

我想通过jbuilder写的程序操纵oracle9i的数据库中的表
例子如下：
package databasemanager;

import java.sql.*;
import java.util.*;

public class Database
{
private Database() {
this.getConnection();
}

private void getConnection() {
try {
String driver = "oracle.jdbc.driver.OracleDriver";
String url = "jdbc:oracle:thin:@192.168.0.123:1521:fangwei";
String username = "system";
String password = "manager";
Class.forName(driver);
Connection conn = java.sql.DriverManager.getConnection(url, username, password);
Statement stmt = conn.createStatement();
}
catch (Throwable ex) {

}
}

public static Database getInstance() {
return new Database();
}

private Statement stmt;
private Connection conn;
// private ResultSet rs;

public int update(String sql) throws SQLException {
return stmt.executeUpdate(sql);
}

public int delete(String sql) throws SQLException {
return stmt.executeUpdate(sql);
}

public ResultSet query(String sql) throws SQLException {
return stmt.executeQuery(sql);
}

public int insert(String sql) throws SQLException {
return stmt.executeUpdate(sql);
}

public void close() {
try {
if (stmt != null) {
stmt.close();
}
}
catch (SQLException ex) {

}
finally {
try {
if (conn != null && !conn.isClosed()) {
conn.close();
}
}
catch (SQLException ex) {

}
}
}

public static void main(String[] args) {
Database db = Database.getInstance();
try {
//
//db.insert("INSERT INTO TABLENAME values('abc',13)");

//db.update("UPDATE ...");

//db.delete("DELETE FROM TABLE...");

db.update("UPDATE COMPANY SET times = times+1");
ResultSet rs = db.query("SELECT * FROM COMPANY");
while (rs.next()) {

}
}
catch (SQLException ex) {

}
finally {
db.close();
}
}
}
问题是我对这块不清楚，不知道查询那块该放到那里，我的查询的条件是：从数据表（company）中查询id，date，times，serial。如果从数据库中查询到这些值的话，返回一个true值，并且修改数据表（company）
中的times使值增加1，否则则返回一个false值，请那位高人讲讲清楚我的这个语句到底该怎样写？并且该放到那？？

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