Question

I initially created an SQLite database on Windows and then had problems accessing it within Android.

Subsequently I created a database on Android and then copied it out. At this point it only had the android_metadata table in it.

I then imported some data via CSV and added it back into my project. The DbHelper class in my project copies the database into /data/data/my.project/databases/.

Now, when I run a raw query from this database, if I try to access the table imported by CSV, I get an error saying that the table doesn’t exist. If I try to access the android_metadata table which I created on Android then there is no error.

The database in my assets definitely has the table in that I wish to copy over to the /data/data/example.project/databases folder and the copy routine is definitely called – I’ve checked with the log output.

Now, if I comment out the copy code, a database is automatically created which contains the android_metadata table in there and it is ~3 KB.

When the copy code is live the database is created as ~8 KB. This is the size of the database in the assets, so it appears that it has been successfully copied. However, when I pull that database back to my desktop from DDMS it is ~8 KB, but it doesn’t contain the table which is in the one in the assets folder. If I manually copy directly from desktop into /data/data… then the database works (but this will not be possible with a market app).

Here is my copy code for copying the database:

public void createDatabase() throws IOException {
    Log.i(TAG, "createDatabase called");

    InputStream assetsDB = mContext.getAssets().open(DATABASE_NAME);
    OutputStream dbOut = new FileOutputStream(DATABASE_PATH);

    Log.i(TAG, DATABASE_PATH);
    Log.i(TAG, assetsDB.toString());

    byte[] buffer = new byte[1024];
    int length;
    while ((length = assetsDB.read(buffer))>0) {
        Log.i(TAG, "WritingDB block" + length);
        dbOut.write(buffer, 0, length);
    }

    dbOut.flush();
    dbOut.close();
    assetsDB.close();
}

How can I fix this problem?

I’ve rectified this using another example which doesn’t override onCreate with the database copy code and handles the copying of the database on its own. I don’t really understand why it doesn’t work when calling the onCreate method.

Answer 1

Have you seen Using your own SQLite database in Android applications?

This page is a good source for the topic. But, there is a little problem. Actually, it is not a problem and explained how to fix in the page. Look at comments.

If your database is sort of largish or smallish (> 1 MB, < 100 KB (I am not sure about these values)). It seems that it is compressed and that causes confusion in the Android read on the InputStream. The trick is to rename your asset to a file that the packager will not try to compress. Renaming the database file from xxx to xxx.mp3 or xxx.txt or something like that does the trick.