안드로이드 SQlite 연동하는 과정에서 문법으로 오류는 없었는데 실행을 시키면 강제중지되어서 질문 올립니다.. 어디가 문제일까요..?

DBhelper 클래스입니다

package com.example.myapplication;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

public class dbHelper extends SQLiteOpenHelper {

public dbHelper(Context context)
{
    super(context, "GoSchoolDB", null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE GoSchoolDB (_id INTEGER PRIMARY KEY AUTOINCREMENT name TEXT tel TEXT);");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS GoSchoolDB");
    onCreate(db);

}

}

MainActivity 클래스입니다

package com.example.myapplication;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteException;

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

dbHelper helper;
SQLiteDatabase db;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    helper = new dbHelper(this);

    try{
        db = helper.getWritableDatabase();
    }catch (SQLiteException e)
    {
        db = helper.getReadableDatabase();
    }
}

}