java로 sql서버 만드는 원리--2(미완성작품)

import java.lang.*;
import java.io.*;
import java.util.*;
 
public class sql{
    public static void main(String[] args) throws Exception{
        Database database=new Database();
        Table table=new Table();
        String Databasename;
 
        Scanner scanner=new Scanner(System.in);
        Console console=System.console();
 
        while(true){
            System.out.print("(Database)sql>");
            String command=scanner.nextLine();
            String[] Strcom=command.split(" ");
 
            if(Strcom.length==3){
                if(Strcom[0].equals("creat")){
                    if(Strcom[1].equals("database"))
                        database.Dmake(Strcom[2]);
                }
                else if(Strcom[0].equals("drop")){
                    if(Strcom[1].equals("database"))
                        database.Ddel(Strcom[2]);
                }
                else{
                    System.out.println("잘못입력하셨습니다.");
                    continue;
                }
            }
            else if(Strcom.length==2){
                if(Strcom[0].equals("use")){
                    database.Dconnect(Strcom[1]);
                    Databasename=Strcom[1]; //데이터베이스 이름을 기록
                    break;
                }
                else{
                    System.out.println("잘못입력하셨습니다.");
                    continue;
                }
            }
            else if(Strcom.length==1){
                if(Strcom[0].equals("show"))
                    database.Dbmenu();
                else if(Strcom[0].equals("quit")){
                    System.out.println("데이터베이스 종료");
                    System.exit(0);
                }
                else{
                    System.out.println("잘못입력하셨습니다.");
                    continue;
                }
 
            }
            else{
                System.out.println("잘못입력하셨습니다.");
                continue;
            }
 
        }
 
        while(true){
            System.out.println("(Table)sql>");
            String command_two=console.readLine();
            String[] Strcom_two=command.split(" ");
 
            if(Strcom_two.length==8){
                if(Strcom_two[0].equals("alter")){
                    if(Strcom_two[1].equals("table")){
                        if(Strcom_two[3].equals("change")){
                            if(Strcom_two[4].equals("column")){
                                Tselect tselect=new Tselect(Strcom_two[2],Strcom_two[5],Strcom_two[7],Strcom_two[6]);
                            }
                        }
                    }
                }
            }
 
 
        }
 
 
    }
}
 
class Database{
 
    List<String> Dlist=new ArrayList<String>();
 
 
    public void Dmake(String args) throws Exception{
        String crname=args;
        Dlist.add(crname);
    }
    public void Ddel(String args) throws Exception{
        String dlname=args;
        Dlist.remove(dlname);
    }
    public void Dbmenu() throws Exception{
        if(Dlist.size()==0){
            Dlist.add(" ");
        }
 
        System.out.println("+----------+");
        for(int i=0;i<Dlist.size();i++){
            String title=Dlist.get(i);
            System.out.printf("|%-10s|\n",title);
        }
        System.out.println("+----------+");
    }
    public void Dconnect(String args) throws Exception{
        for(String str:Dlist){
            if(str.equals(args)){
                System.out.println(str+"데이터베이스 선택");
            }
        }
    }
}
 
class Table {
    List<String> Tlist=new ArrayList<String>();
    int SIZE;
    String[][] bstr=new String[1][SIZE];
    Integer[][] bint=new Integer[1][SIZE];
 
    String cott[SIZE];
 
    Scanner scanner=new Scanner(System.in);
 
    public void Tmake(String args) throws Exception{
        String crname=args;
        Tlist.add(crname);
 
 
        //입력
        for(int j=0;j<1;j++){
            for(int i=0;i<3;i++){
                System.out.print("필드 속성값:");
                String icon=console.readLine();
                String cott[i]=icon;
                String[] names=icon.split(" ");
 
                String haha=new String(names[0]);
                String gaga=new String(names[1]);
        //초기값할당
                if(gaga.equals("String")){
                    bstr[j][i]=new String(" ");
                }
                else if(gaga.equals("Integer")){
                    bint[j][i]=new Integer(0);
                }
 
            }
        }
    }
    public void Tdel(String args) throws Exception{
        String dlname=args;
        Tlist.remove(dlname);
    }
    public void Tbmenu(String args) throws Exception{
        if(Tlist.size()==0){
            Tlist.add(" ");
        }
 
        System.out.println("+----------+");
        for(int i=0;i<Tlist.size();i++){
            String title=Tlist.get(i);
            System.out.printf("|%-10s|\n",title);
        }
        System.out.println("+----------+");
 
    }
    public void Talter(String args) throws Exception{
 
    }
 
}
 
class Tselect extends Table{
    Tselect(String tablename,String fieldname,String fieldtype,String newfieldname){
 
    }//테이블 필드 변경 생성자
    Tselect(String tablename,String fieldname,String fieldtype){
 
    }//테이블 필드 추가 생성자
    Tselect(String tablename,String fieldname){
 
    }//테이블 필드 삭제 생성자
}