App keeps crashing when a button is pressed

Every time I try to run my app, it crashes when I press a button. LogCat says that the cause

is in this file. Here are the LogCat messages and the file that is causing the crash supposedly. thank you for any and all help.

Here is the file where the error is:

package com.example.drive.drivercorder;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;



public class dbadapter {

private static final String TAG = "DBAdapter";

public static final String KEY_ROWID = "_id";
public static final int COL_ROWID = 0;

public static final String KEY_DRIVETIME = "Drive Time";
public static final String KEY_NIGHTORDAY = "Time of Day";



public static final int COL_DRIVETIME = 1;
public static final int COL_NIGHTORDAY = 2;



public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_DRIVETIME,    
KEY_NIGHTORDAY, };


public static final String DATABASE_NAME = "MyDb";
public static final String DATABASE_TABLE = "mainTable";

public static final int DATABASE_VERSION = 2;   

private static final String DATABASE_CREATE_SQL = 
        "create table " + DATABASE_TABLE 
        + " (" + KEY_ROWID + " integer primary key autoincrement, "

        + KEY_DRIVETIME + " integer not null, "
        + KEY_NIGHTORDAY + " text not null "



        + ");";


private DatabaseHelper myDBHelper;
private SQLiteDatabase db;



public dbadapter(Context ctx) {
    myDBHelper = new DatabaseHelper(ctx);
}


public dbadapter open() {
    db = myDBHelper.getWritableDatabase();
    return this;
}


public void close() {
    myDBHelper.close();
}


public long insertRow(int drivetime, String nightorday) {

    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_DRIVETIME, drivetime);
    initialValues.put(KEY_NIGHTORDAY, nightorday);



    return db.insert(DATABASE_TABLE, null, initialValues);
}




public Cursor getAllRows() {
    String where = null;
    Cursor c =  db.query(true, DATABASE_TABLE, ALL_KEYS, 
                        where, null, null, null, null, null);
    if (c != null) c.moveToFirst();
    return c;
}


public Cursor getRow(long rowId) {
    String where = KEY_ROWID + "=" + rowId;
    Cursor c =  db.query(true, DATABASE_TABLE, ALL_KEYS, 
                    where, null, null, null, null, null);
    if (c != null) {
        c.moveToFirst();
    }
    return c;
}


public boolean updateRow(long rowId, int drivetime, String nightorday) {
    String where = KEY_ROWID + "=" + rowId;

    ContentValues newValues = new ContentValues();
    newValues.put(KEY_DRIVETIME, drivetime);
    newValues.put(KEY_NIGHTORDAY, nightorday);

    return db.update(DATABASE_TABLE, newValues, where, null) != 0;
}


private static class DatabaseHelper extends SQLiteOpenHelper{
    DatabaseHelper(Context context) {

        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase _db) {
        _db.execSQL(DATABASE_CREATE_SQL);
    }

    @Override
    public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
        Log.w(TAG, "Upgrading application's database from version " + oldVersion
                + " to " + newVersion + ", which will destroy all old data!");

        _db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);


        onCreate(_db);
    }
}

}