package number;


import java.sql.*;
public class Gradation {
static Connection con;
static Statement sql;
static ResultSet res;
public Connection getConnection() {
try {
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
con = DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433; DatabaseName=db_jdbc","sa","");
System.out.println("数据库连接成功");
} catch (Exception e) {
e.printStackTrace();
}
return con;
}
public static void main(String[] args) {
Gradation c = new Gradation();
con = c.getConnection();
try {
sql = con.createStatement();
res = sql.executeQuery("select * from tb_stu");
while (res.next()) {
String id = res.getString("id");
String name = res.getString("name");
String sex = res.getString("sex");
String brithday = res.getString("brithday");
System.out.print("编号：" + id);
System.out.print(" 姓名" + name);
System.out.print(" 性别:" + sex);
System.out.println(" 生日：" + brithday);
}
} catch (Exception e) {
e.printStackTrace();
}

}

}



代码如上：运行后

数据库连接成功
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]对象名 'tb_stu' 无效。
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processErrorToken(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReplyToken(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSExecuteRequest.processReplyToken(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplStatement.getNextResultType(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.commonTransitionToState(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.postImplExecute(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.commonExecute(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.executeQueryInternal(Unknown Source)
at com.microsoft.jdbc.base.BaseStatement.executeQuery(Unknown Source)
at number.Gradation.main(Gradation.java:24)

代码里第24行是这一句，res = sql.executeQuery("select * from tb_stu");
望解答，是不是数据库里没有tb_stu表啊，怎么查看？
我再SQL2K加了光盘里的db_jdbc_Data.MDF还是报一样的错误，请解答，拜谢！