Question

I have a view in which I am inserting data in a background thread to sqlite database coming from server. Now when user taps and navigate to another view in which I have to read the contents from this database, but I am not able to fetch the contents as the database is already open in background thread of last view and it gives error “database is locked”.

NOTE: both the operations are in different Tables i.e I am writing in different table and reading from other table.

Does sqlite support multi threading, If yes then how can I remove the lock from database?

Answer 1

SQLite supports multithreading. You can share your connection handle/object between threads, they’ll sync their access nicely.

EDIT: pass the sqlite3 object (the one that sqlite3_open() returns as the second parameter) to the thread instead of reopening the database in the thread. Something like this:

sqlite3 *MyDatabase; //Initialized somewhere
NSArray *DataForThread = [NSArray arrayWithObjects:
    request,
    [NSValue valueWithPointer: MyDatabase],
    nil];

[self performSelectorInBackground:@selector(processResponseInBackground:)        withObject:DataForThread];

Inside the thread, recover the SQLite3 object like this:

sqlite3 *MyDatabase = [[ThreadData objectAtIndex:1] pointerValue];