A sample code that shows how the SQLiteOpenHelper works

SubjectDbHelper.java

package com.markojerkic.gradetrack.subjectData;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class SubjectDbHelper extends SQLiteOpenHelper {

    private static final String SQL_CREATE_ENTRIES =
            "CREATE TABLE " + SubjectFeedReaderConctact.SubjectFeedEntry.TABLE_NAME + " (" + //Creating a table named in the FeedEntery class
                    SubjectFeedReaderConctact.SubjectFeedEntry._ID + " INTEGER PRIMARY KEY," + //_ID should always be INTEGER PRIMARY KEY 
                    SubjectFeedReaderConctact.SubjectFeedEntry.COLUMN_SUBJECT + " TEXT," +  //Creating a column named in the FeedEntery 
                    SubjectFeedReaderConctact.SubjectFeedEntry.COLUMN_AVG_GRADE + " INTEGER)";//Creating a clumn named in the FeedEntery

  //Most of the time ,you will not need to change these methods
  //Just write them like this
    private static final String SQL_DELETE_ENTRIES =
            "DROP TABLE IF EXISTS " + SubjectFeedReaderConctact.SubjectFeedEntry.TABLE_NAME;

    public static final int SUBJECTS_DATABASE_VERSION = 1;
    public static final String SUBJECTS_DATABASE_NAME = "Subject.db";

    public SubjectDbHelper(Context context) {
        super(context, SUBJECTS_DATABASE_NAME, null, SUBJECTS_DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        sqLiteDatabase.execSQL(SQL_CREATE_ENTRIES);
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
        sqLiteDatabase.execSQL(SQL_DELETE_ENTRIES);
        onCreate(sqLiteDatabase);
    }

    @Override
    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        super.onDowngrade(db, oldVersion, newVersion);
    }
}