数据库查询问题??在线等待回答!!
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??