arguments in sqlite3_open()
?: is the ternary operator, explained here.
In this particular instance it's a shortcut way of writing:
int err;if (databasePath) err = sqlite3_open([databasePath fileSystemRepresentation], &db);else err = sqlite3_open(":memory:", &db);if (err != SQLITE_OK) {But, as I'm sure you'll agree, much more concise.
? followed by : is called "Ternary operator".
The line (databasePath ? [databasePath fileSystemRepresentation] : ":memory:") means:
If databasePath is true, use [databasePath fileSystemRepresentation], else use ":memory:".
The line is the one-liner edition of the following:
if(databasePath) { return [databasePath fileSystemRepresentation];} else { return ":memory:";}:memory: is In-Memory Database. See the docs for more information.