In Android, check if sqlite database exists fails from time to time

Question

In Android I use the following method to see if the sqlite database exist and if I can open it and use it.

If it fail this test I copy the database file from the assets (this should only happen once, when the user first start the app).

/*
* Check if the database already exist to avoid re-copying the file each time you open the application.
* @return true if it exists, false if it doesn't
*/
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.
    }

    if(checkDB != null){
        checkDB.close();
    }
    return checkDB != null ? true : false;
}

The problem is that I get reports from users saying that their data has been wiped out and when investigating I can see that the database is replaced with the database from the assets. So for some reason even if the user already has a database file sometimes the SQLiteDatabase.openDatabase() throws an error. I haven't been able to reproduce the issue myself but it seems to happen for some users.

Anyone have an idea what the problem might be here? Is there a better way to do this test?

Please help with this http://stackoverflow.com/questions/20728808/android-reading-stored-sqlite-database — gandharv09, Dec 22 '13 at 11:35

score 33 · Accepted Answer · answered Nov 04 '11 at 15:00

33

How about just checking the filesystem to see if the database exists instead of trying to open it first?

You could be trying to open a database that is already open and that will throw an error causing you to think it does not exist.

File database=getApplicationContext().getDatabasePath("databasename.db");

if (!database.exists()) {
    // Database does not exist so copy it from assets here
    Log.i("Database", "Not Found");
} else {
    Log.i("Database", "Found");
}

answered Nov 04 '11 at 15:00

Kuffs

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This does not work for me! See http://stackoverflow.com/questions/18391820/checking-if-database-exists – Ahmed Zafar Aug 22 '13 at 22:37
3

I was just trying to contact the OP so that he might help me. I did post my own question and the link is given above. I'm not 'polluting' anything merely asking for help which is this website's purpose. – Ahmed Zafar Aug 23 '13 at 08:14

score 3 · Answer 2 · answered Jan 26 '14 at 08:35

I want to share a method to check if database exists: Give me a +1 if it runs fine for you, Thanks.

private boolean checkDataBase() {

    SQLiteDatabase checkDB = null;

    try {

        File database=myContext.getDatabasePath(DB_NAME);

        if (database.exists()) {

            Log.i("Database", "Found");

            String myPath = database.getAbsolutePath();

            Log.i("Database Path", myPath);

            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        } else {                

            // Database does not exist so copy it from assets here
            Log.i("Database", "Not Found");

        }

    } catch(SQLiteException e) {

        Log.i("Database", "Not Found");

    } finally {

        if(checkDB != null) {

            checkDB.close();

        }

    }

    return checkDB != null ? true : false;
}

Not a good method as it suffers from the same issue that the OP encountered. If the database exists but cannot be opened it reports that it does not exist. Checking whether a database exists and whether it can be opened should be independent operations if you need to do both. Also this is relying on an exception being thrown to determine the database state which is not good practice. — Kuffs, Jul 28 '15 at 13:24

In Android, check if sqlite database exists fails from time to time

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