Database Helper Class Example

public class DBHelper extends SQLiteOpenHelper

{

       private static final String DATABASE_NAME = "Student";

       private static final int DATABASE_VERSION =  1;

       private static final String TABLE_USER = "Marks";

       private SQLiteDatabase db;

       private static String DB_PATH = "";

       private Context mycontext;

       private String today;

       private static String CREATE_TABLE_USER = "create table Marks (ASid integer primary key autoincrement, Name text, Marks integer);";

      

public DBHelper(Context context) {

            

super(context, DATABASE_NAME, null, DATABASE_VERSION);

       DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";

}

@Override

public void onCreate(SQLiteDatabase db) {

       //db.execSQL(CREATE_TABLE_USER);

}

public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {}

public static boolean isTableExist(SQLiteDatabase db)

{

Cursor cursor = db.rawQuery("select DISTINCT tbl_name from sqlite_master where tbl_name = '"+TABLE_USER+"'", null);

       if(cursor!=null)

{

if(cursor.getCount()>0)

             {

                  cursor.close();

                  return true;

             }

             cursor.close();

            

    }

return false;

}

            

            

private static boolean isDataBaseExist()

{           

       File file =new File(DB_PATH + DATABASE_NAME);       

       return file.exists();

}

public DBHelper opendb() throws SQLException

{

isDataBaseExist();

       if (isDataBaseExist() == false)

       {

              db=getWritableDatabase();

              if (db.isOpen())

                    db.close();

       }

      

db = getWritableDatabase();

       boolean tableExsist = isTableExist(db);

      

if(! tableExsist)

       {

              db.execSQL(CREATE_TABLE_USER);

       }

       return this;

       }

       public void closedb() {

              db.close();

       }

      

       public void AddRecords(String Name, Integer Marks)

       {

              Date d = new Date();

              SimpleDateFormat curFormater = new SimpleDateFormat("dd/MM/yyyy");

              String today = curFormater.format(d);

                   

              try

              {

                    ContentValues initialValues = new ContentValues();

                    db =  getWritableDatabase();    

                    initialValues.put("Name", Name);

                    initialValues.put("Marks", Marks);

                    db.insert(TABLE_USER, null, initialValues);

                    }

                    catch(Exception e)

                    {

                           e.printStackTrace();

                    }

             }

            

       public boolean CheckASList(String Name, Integer Marks)

             {

                    db = getReadableDatabase();

                    boolean flg = false;

                    try

                    {

                           Cursor cursor = db.query(TABLE_USER,

                            null, "Name" + " = '" + Name +"'"  +" AND " + "Marks" + " = '" + Marks+"'", null,null, null, null);

                          

                    int size = cursor.getCount();

                    if(size > 0)

                    {

                           flg = true;               

                    }

                    }

                    catch(Exception e)

                    {

                           e.printStackTrace();

                    }

                    return flg;

             }

      

       public ArrayList<ListBean> SelectStudentList(Integer Marks)

       {

             db = getReadableDatabase();

            

            

             ArrayList<ListBean> Beans= new ArrayList<ListBean>() ;

             boolean flg = false;

             try

             {

                    Cursor cursor = db.query(TABLE_USER,

                            null, "Narks" + " > '" + Marks +"'"  , null,

                            null, null, null);

                   

                    int size = cursor.getCount();

                    if(size > 0)

                    {     

                           cursor.moveToFirst();

                           for(int i=0; i<size; i++)

                           {

                                  flg = true;

                                  String Name = cursor.getString(0);

                                  String Marks= cursor.getString(1);

                                  ListBean ASbean = new ListBean() ;

                                  ASbean.setName(Name);

                                  ASbean.Marks(Marks);

                                

Beans.add(i, ASbean);

                                  cursor.moveToNext();

                           }     

                           cursor.close();

                    }

             }

             catch(Exception e)

             {

                    e.printStackTrace();

             }

             return Beans;

       }

      

       public int getCount()

       {

             db = getReadableDatabase();

             Cursor cursor = db.query(TABLE_USER,

                     null, null, null,

                     null, null, null);

             int size = cursor.getCount();

             return size;

       }

}