Question

we all know the android system database should be stored in /data/data/package name/ directory,there is a existing database i want to use in my application.

some people might tell me just put the orginal database in the /res/raw/ directory,and then use FileInputStream to read it, read into things FileOutStream to write to that directory. that’s a good idea,

But the problem is that not all of the phones have root access for you to access the system directory, And also i can’t just put the db file in the sdcard and read data from there,because you didn’t know if there is a sdcard in the phone either. I really have no idea for this, Did anyone can give me a hand? i appreciate for that.

Answer 1

I have an 80 megabyte SQLite database that I converted from Microsoft Access 10. I download it to 1) the phone’s sdcard, 2) sdcard-ext, or 3) internal storage depending on available space. The SQLite database was created on a PC using SQLite 3.7.4. It runs fine on Androids from version 2.2 (8) and up. For processing I created a DatabaseAdapter class that does not use open helper.

Here’s the database open from my DatabaseAdapter class:

public DatabaseAdapter open() {
    MyLog.d(TAG, "open");
    try {
        String databaseFile = databasePath + File.separator
                + GC.DATABASE_NAME;
        theDB = SQLiteDatabase.openDatabase(databaseFile, null,
                SQLiteDatabase.OPEN_READONLY
                        | SQLiteDatabase.NO_LOCALIZED_COLLATORS);
    } catch (SQLiteException e) {
        MyLog.d(TAG, "open error: " + e.getMessage());
        theDB = null;
    }
    if (theDB == null) {
        return null;
    }
    return this;
}

The constructor passes the path. The sequence of use is

    DatabaseAdapter dbAdapter = new DatabaseAdapter(databasePath);

    if (dbAdapter.open() == null) {
        // ooops. no database open...
        return;
    }

    Cursor cursor = dbAdapter.someQuery(arg1, where, limit);
    if (cursor != null)
        while (cursor.moveToNext()) {
           field1 = cursor.getString(0);
           // etc.
        }
        cursor.close();
    }

    dbAdapter.close();

The key to the external database open is the NO_LOCALIZED_COLLATORS flag. Without it, the open will try to access the Android created localization table. When creating external databases, the table isn’t created and, when run on a phone, a table not found blow up occurs.

To determine the path you want to use for the database, use Environment.getExternalStorageState() and use the sdcard or internal storage accordingly.

Use getExternalStorageDirectory() to get the sdcard directory. Use this.getApplicationContext().getFilesDir()
.getPath() to get the internal storage path. Assuming that you if’d the local or external path into databasePath, you can download the database into an output file created as

File downloadOutput = new File(databasePath, “mysqlite.db”);

After it is downloaded, you can use the open() illustrated above to ready your database for access. (Note: the database can be opened as writable, not just read only as shown.)

Hope I didn’t over explain…