Viewing sqlite3_stmt* in command window - objective-c

Question

I have inherited a SQLite database that is poorly commented and I need to understand what it is querying and receiving. Is there a way to see the value a sqlite3_stmt pointer is pointing to? Is it something that can be printed to the console in a printf() or NSLog()?
Thanks

Answer 1

The best way to do it is to trace the compiled statement. I've found a solution with the help of this question:
The sqlite3_trace command triggers a callback, which you need to code yourself. Once the trace is turned on it will execute for the rest of the program.
I've got all my database access routines in a single class, and I've used this as the callback function (it's a C function, not a method).
void traceCallback( void* udp, const char* sql )
{
printf("{SQL} [%s]\n", sql);
}
I turned the trace on in an init database method: it's turned on once the database is opened.
-(void)initializeDatabase
{
NSString *path = [self createEditableCopyOfDatabaseIfNeeded];
// open the db
if (sqlite3_open([path UTF8String], &db) == SQLITE_OK)
sqlite3_trace(db, traceCallback, NULL);
else {
// error - cleanup
sqlite3_close(db);
NSLog(#"Error opening db");
NSLog(#"Path: %#",path);
}
}
This will turn a SQL statement with bound variables into a string.
From this:
const char *sql2 = "select a.key, b.key from words a left outer join known_words b on a.key = b.word_id where a.word_foreign = :word_foreign";
To this:
{SQL} [select a.key, b.key from words a left outer join known_words b on a.key = b.word_id where a.word_foreign = 'bak.']