Question

I created in-memory database in Android. I put null in name parameter in SQLiteOpenHelper constructor:

SQLiteOpenHelper(context, null, null, 1);

Also I created some doc_orders_products table in the in-memory db.

Now I’m trying attach this in-memory db to my main on-disk db.
What name of in-memory db should I use in ATTACH command?

I tried:

mainDB.execSQL("ATTACH DATABASE ':memory:' AS temp_db");

and

mainDB.execSQL("ATTACH DATABASE '' AS temp_db");

Both ATTACH command performs well even when in-memory db isn’t created at all.
But when I try get access to tables in the in-memory db, they are not present. I get exception. E.g.:

10-11 14:07:46.782: E/AndroidRuntime(2107): Caused by: 
android.database.sqlite.SQLiteException: no such table: 
temp_db.doc_orders_products (code 1): , while compiling: 
INSERT INTO temp_db.doc_orders_products SELECT * FROM 
main.doc_orders_products WHERE doc_id=3

Is it possible to attach in-memory db to on-disk db? What correct way is to do it?

Thanks.

Answer 1

Every new connection to an in-memory database creates a new, empty database.
So your ATTACH commands attached to a different database.

What you should do is to use the ATTACH command and then create your tables, through the mainDB connection, in the temp_db database; e.g. CREATE TABLE temp_db.doc_orders_products(....