Basic DataBase for Android

package com.app.util;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;


public class AppDbAdapter {

    private static final String DATABASE_NAME = "app.db";
    private static final String DATABASE_TABLE_COURSES = "courses";

    private static final int DATABASE_VERSION = 1;

    public static final String KEY_ID = "_id";
    public static final String KEY_COURSE_CID = "cid";
    public static final String KEY_COURSE_CNAME = "cname";
    public static final String KEY_COURSE_COUNT = "cdcount";


    private static final String DATABASE_CREATE_COURSE = "create table "            + DATABASE_TABLE_COURSES + " (" + KEY_ID            + " integer primary key autoincrement, " + KEY_COURSE_CID            + " integer, " + KEY_COURSE_CNAME + " text, " + KEY_COURSE_COUNT            + " integer);";


    // Variable to hold the database instance    private SQLiteDatabase db;

    // Context of the application using the database.    private final Context context;

    // Database open/upgrade helper    private DBHelper dbHelper;

    public AppDbAdapter(Context _context) {
        context = _context;
        dbHelper = new DBHelper(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    public AppDbAdapter open() throws SQLException {
        db = dbHelper.getWritableDatabase();
        return this;
    }

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

    public synchronized Cursor getAllCourses() {
        Cursor cursor = null;
        try {
            final String SQL_STATEMENT = "SELECT * FROM "                    + DATABASE_TABLE_COURSES + " order by " + KEY_COURSE_CID;

            cursor = db.rawQuery(SQL_STATEMENT, null);
        } catch (Exception e) {
            // TODO: handle exception            e.printStackTrace();
        }

        return cursor;
    }


   /* public long insertEntry(Document objDoc) {
        ContentValues contentValues = new ContentValues();        try {

            contentValues.put(KEY_COURSE_CID, objDoc.cid);            contentValues.put(KEY_DOCUMENT_DID, objDoc.id);            contentValues.put(KEY_DOCUMENT_PATH, objDoc.filepath);            contentValues.put(KEY_DOCUMENT_IMAGE_PATH, objDoc.imagePath);            contentValues.put(KEY_DOCUMENT_DATE, objDoc.date);            contentValues.put(KEY_DOCUMENT_NAME, objDoc.name);
        } catch (Exception e) {            // TODO: handle exception
            e.printStackTrace();        }        return db.insert(DATABASE_TABLE_DOCS, null, contentValues);    }*/
    public void truncateCourseTable() {

        try {
            db.execSQL("DROP TABLE " + DATABASE_TABLE_COURSES);

            db.execSQL(DATABASE_CREATE_COURSE);
        } catch (Exception ce) {
            ce.printStackTrace();
        }
    }

   /* public void truncateDocsTable() {
        try {            db.execSQL("DROP TABLE " + DATABASE_TABLE_DOCS);
            db.execSQL(DATABASE_CREATE_DOCS);        } catch (Exception ce) {            ce.printStackTrace();        }    }*/
    private static class DBHelper extends SQLiteOpenHelper {
        public DBHelper(Context context, String name, CursorFactory factory,
                        int version) {
            super(context, name, factory, version);
        }

        // Called when no database exists in disk and the helper class needs to        // create a new one        @Override        public void onCreate(SQLiteDatabase _db) {

            try {
                _db.execSQL(DATABASE_CREATE_COURSE);

            } catch (Exception e) {
                // TODO: handle exception                e.printStackTrace();
            }

        }

        @Override        public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

        }
    }
}