Databases
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    <p>From my development experience , I always prefer to add a prepared sqlite database file in the /res/raw folder.You create/manage sqlite database using Sqlite Manager addon of Firefox , it's a great tool. This method is really great because </p> <ul> <li>firstly I don't need to write a bunch of codes for creating/managing database.</li> <li>Most importantly , some applications needs to read from a pre-populated database. I don't need to care about what the app requires and whether database is empty or filled already. It serves all purpose. I just need to write some methods that runs the required simple sqls.</li> </ul> <p>Here is my own customised DatabaseHelper class. To use this class you'll need to follow some instructions.</p> <ol> <li>If sqlite database size is more than 1MB then split the file into chunks , I prefer 512KB chunks and place them into /res/raw directory.</li> <li><p>Edit the package name and your db file names in the following class.</p> <pre><code>package your.packagee.name; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import android.content.Context; import android.content.res.Resources; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteException; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; import android.widget.Toast; public class DataBaseHelper extends SQLiteOpenHelper { private static final String pkg = "your package name"; private static String DB_PATH = "/data/data/" + pkg + "/databases/"; private static String DB_NAME = "yourDBFile.sqlite"; int[] dbfiles = { R.raw.chunk1 , R.raw.chunk2 ..... }; private SQLiteDatabase myDataBase; private final Context myContext; public DataBaseHelper(Context context) { super(context, DB_NAME, null, 1); this.myContext = context; } public void createDataBase() { boolean dbExist = checkDataBase(); if (dbExist) { // do nothing - database already exist } else { this.getReadableDatabase(); try { CopyDataBase(); } catch (IOException e) { Toast.makeText(myContext, e.getMessage(), Toast.LENGTH_SHORT) .show(); Log.d("Create DB", e.getMessage()); } } } private boolean checkDataBase() { SQLiteDatabase checkDB = null; try { String myPath = DB_PATH + DB_NAME; checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS); } catch (SQLiteException e) { Toast.makeText(myContext, e.getMessage(), Toast.LENGTH_SHORT) .show(); Log.d("Check DB", e.getMessage()); } if (checkDB != null) { checkDB.close(); } return checkDB != null ? true : false; } private void CopyDataBase() throws IOException { InputStream databaseInput = null; Resources resources = myContext.getResources(); String outFileName = DB_PATH + DB_NAME; OutputStream databaseOutput = new FileOutputStream(outFileName); byte[] buffer = new byte[512]; int length; for (int i = 0; i &lt; dbfiles.length; i++) { databaseInput = resources.openRawResource(dbfiles[i]); while ((length = databaseInput.read(buffer)) &gt; 0) { databaseOutput.write(buffer, 0, length); databaseOutput.flush(); } databaseInput.close(); } databaseOutput.flush(); databaseOutput.close(); } public void openDataBase() throws SQLException { String myPath = DB_PATH + DB_NAME; myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS); } @Override public synchronized void close() { if (myDataBase != null) myDataBase.close(); super.close(); } @Override public void onCreate(SQLiteDatabase db) { } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { } public boolean deleteItem (String ID){ String query = "delete from item where id='" + ID + "'" ; Log.d("Query : ", query); try{ myDataBase.execSQL(query); return true ; } catch (Exception e){ Log.d("Exception", e.toString()); return false ; } } public Cursor getSearchFromID(String id) { return myDataBase.rawQuery("select * from item where id = \"" + id + "\"", null); } public boolean addSave(String type, String data , String time) { String query = "insert into item (type, data , timestamp) values ('" + type + "', '" + data + "', '" + time + "')"; try { myDataBase.execSQL(query); return true ; } catch (Exception e) { return false ; } } } </code></pre></li> </ol> <p>Here's some methods written as a sample , how to use it.</p> <p>Usage is simple. When your application starts , that means in your Launcher activity use this code to initialize your database</p> <pre><code>DataBaseHelper helper = new DataBaseHelper(this); helper.createDataBase(); helper.openDataBase(); helper.close(); </code></pre> <p>Then just use the methods written in DatabaseHelper class. A sample will be like this</p> <pre><code> String id = "1"; DataBaseHelper helper = new DataBaseHelper(this); helper.openDataBase(); Cursor c = helper.getSearchFromID(id); if(c.getCount() &gt; 0){ c.moveToFirst(); while(!c.isAfterLast()){ // extract your data from cursor c.MoveToNext(); } } </code></pre> <p>Hope it will solve your all problems about sqlite database in Android. At least it solved for me. Thank you.</p>
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    1. COThanx Ayon. You're correct. It solves my problems.Thanx again.
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    2. COSounds great !! :)
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    3. COThen what should I do with my DBAdapter class ?I know I can use it for inserting data into database. But I am little doubt. If I use DBAdapter class to insert data into database, then should I use createDataBase(), openDatabase() and closeDatabase() same as in the DataBaseHelper class? Because, a tutorial is doing such a scenario. Can you plz give me an example? Thanx
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