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upgrade a database without removing the data - code segment one
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public class DatabaseHelper extends SQLiteOpenHelper { | |
//The Android's default system path of your application database. | |
private static String DB_PATH = "/data/data/test.test/databases/"; | |
private static String DB_NAME = "TestDatabase"; | |
private static final int DB_VERSION = 1; | |
private SQLiteDatabase myDatabase; | |
private final Context myContext; | |
/** | |
* # Constructor # | |
* Takes and keeps a reference of the passed context in order to access to the application assets and resources. | |
* | |
* @param context | |
*/ | |
public DatabaseHelper(Context context) { | |
super(context, DB_NAME, null, DB_VERSION); | |
this.myContext = context; | |
}//constructor | |
/** | |
* # Create Database # | |
* Creates a empty database on the system and rewrites it with your own database. | |
*/ | |
public void createDatabase() throws IOException { | |
boolean dbExist = checkDatabase(); | |
if (dbExist) { | |
//do nothing - database already exist | |
}//if | |
else { | |
//By calling this method and empty database will be created into the default system path | |
//of your application so we are gonna be able to overwrite that database with our database. | |
this.getReadableDatabase(); | |
try { | |
copyDatabase(); | |
} catch (IOException e) { | |
throw new Error("Error copying database"); | |
}//catch | |
}//else | |
}//createDatabase | |
private boolean checkDatabase() { | |
SQLiteDatabase checkDB = null; | |
try { | |
String myPath = DB_PATH + DB_NAME; | |
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); | |
} catch (SQLiteException e) { | |
//database does't exist yet. | |
}//catch | |
if (checkDB != null) { | |
checkDB.close(); | |
}//if | |
return checkDB != null ? true : false; | |
}//checkDatabase | |
private void copyDatabase() throws IOException { | |
//Open your local db as the input stream | |
InputStream myInput = myContext.getAssets().open(DB_NAME); | |
// Path to the just created empty db | |
String outFileName = DB_PATH + DB_NAME; | |
//Open the empty db as the output stream | |
OutputStream myOutput = new FileOutputStream(outFileName); | |
//transfer bytes from the inputfile to the outputfile | |
byte[] buffer = new byte[1024]; | |
int length; | |
while ((length = myInput.read(buffer)) > 0) { | |
myOutput.write(buffer, 0, length); | |
} | |
//Close the streams | |
myOutput.flush(); | |
myOutput.close(); | |
myInput.close(); | |
}//copyDatabase | |
// # open database # | |
public void openDatabase() throws SQLException { | |
//Open the database | |
String myPath = DB_PATH + DB_NAME; | |
myDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE); | |
}//openDatabase | |
@Override | |
public synchronized void close() { | |
if (myDatabase != null) | |
myDatabase.close(); | |
super.close(); | |
}//close | |
@Override | |
public void onCreate(SQLiteDatabase db) { | |
} | |
@Override | |
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { | |
} | |
public List<String> selectData | |
(String tableName, String[] columns, String selection, String[] selectionArgs, | |
String groupBy, String having, String orderBy) { | |
List<String> list = new ArrayList<String>(); | |
Cursor cursor = this.myDatabase.query(tableName, columns, selection, selectionArgs, groupBy, having, orderBy); | |
if (cursor.moveToFirst()) { | |
do { | |
list.add(cursor.getString(0)); | |
} | |
while (cursor.moveToNext()); | |
} | |
if (cursor != null && !cursor.isClosed()) { | |
cursor.close(); | |
} | |
return list; | |
}//selectData | |
public void insertData(String tableName, String nullColumnHack, ContentValues values) { | |
try { | |
myDatabase.insert(tableName, nullColumnHack, values); | |
} catch (Exception e) { | |
Log.e("Error :", "unable to insert data"); | |
}//catch | |
}//insertData | |
//edit row | |
public void updateData(String tableName, ContentValues values, String whereClause, String[] whereArgs) { | |
try { | |
myDatabase.update(tableName, values, whereClause, whereArgs); | |
} catch (Exception e) { | |
Log.e("Error :", "unable to update data"); | |
}//catch | |
}//updateData | |
public void deleteRow(String tableName, String whereClause, String[] whereArgs) { | |
try { | |
myDatabase.delete(tableName, whereClause, whereArgs); | |
} catch (Exception e) { | |
Log.e("Error :", "unable to delete row"); | |
}//catch | |
}//deleteRow | |
} |
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this code segment doesn
t work, you don
t want to use this.