package first;

import java.sql.*;

public class CDatabase {
	boolean isconnected, eors, bors, isqueried;
	String url, user, pwd;
	Connection con;
	Statement st;
	ResultSet rs;
	ResultSetMetaData rsmd;
	DatabaseMetaData dbmt;
	
	protected void init(String DataSourceName, String Username, String Password){
		url = "jdbc:odbc:" + DataSourceName;
		user = Username;
		pwd = Password;
		eors = false;
		bors = false;
		isconnected = false;
		isqueried = false;
	}
	public CDatabase(String DataSourceName, String Username, String Password){
		init (DataSourceName, Username, Password);
	}
	public CDatabase(String DataSourceName){
		init (DataSourceName, "", "");
	}
	public String getInf(){
		String result = "";
		int i;
		try{
			if (rs.next()){
				for (i=1; i<=rsmd.getColumnCount(); i++){
					result += rs.getString(i) + ";";
				}
				eors = false;
				return (result);
			}else{
				eors = true;
				return ("EORS");
			}
		}catch (Exception ex){
			System.out.println(ex.getMessage());
			ex.printStackTrace ();
			return (ex.getMessage());
		}
	}	
	public String disconnect(){
		try{
			isconnected = false;
			con.close();
			return ("");
		}catch (Exception ex){
			System.out.println(ex.getMessage());
			ex.printStackTrace ();
			return (ex.getMessage());
		}
	}
	public String connect(){
		try{
			//加載驅動程序
			Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
			//建立連接
			con=DriverManager.getConnection(url, user, pwd);
			
			isconnected = true;
			//使用DatabaseMetaData 對象獲取數據源相關信息
			dbmt=con.getMetaData();
			return ("");
/*			//獲得數據源URL
			System.out.println("Data Source URL: "+dbmt.getURL());
			
			//獲得驅動程序名稱
			System.out.println("Driver Name: "+dbmt.getDriverName());
			//獲得驅動程序版本號
			System.out.println("Driver Version: "+dbmt.getDriverVersion());
			//獲得數據源連接的DBMS 名稱
			System.out.println("Dtabase ProductName:"+dbmt.getDatabaseProductName());
			//獲得數據源連接的DBMS 版本號
			System.out.println("Dtabase ProductVersion:"+dbmt.getDatabaseProductVersion());
*/
		}catch(Exception ex){
			System.out.println(ex.getMessage());
			ex.printStackTrace ();
			return (ex.getMessage());
		}
	}
	public String close(){
		try{
			rs.close();
			st.close();
			eors = false;
			bors = false;
			isqueried = false;
			return ("");
		}catch (Exception ex){
			System.out.println(ex.getMessage());
			ex.printStackTrace ();
			return (ex.getMessage());
		}
	}
	public String query(String SqlStr){
		try{
			//使用Statement、ResultSet、ResultSetMetaData查詢數據庫
			if (isqueried){
				this.close();
			}
			st = con.createStatement();
			rs = st.executeQuery(SqlStr);
			rsmd = rs.getMetaData();
			isqueried = true;
			return ("");
		}catch (Exception ex){
			System.out.println(ex.getMessage());
			ex.printStackTrace ();
			return (ex.getMessage());
		}
	}
	public String execute(String SqlStr){
		try{
			//使用Statement、ResultSet、ResultSetMetaData查詢數據庫
			if (isqueried){
				this.close();
			}
			st = con.createStatement();
			st.execute(SqlStr);
			return ("");
		}catch (Exception ex){
			System.out.println(ex.getMessage());
			ex.printStackTrace ();
			return (ex.getMessage());
		}
	}
}