Question

I get “unable to open database file” when executing rc = sqlite3_open(“test.db”, &db); ??

sqlite3 *db; // sqlite3 db struct
char *zErrMsg = 0;
int rc;

// Open the test.db file
rc = sqlite3_open("test.db", &db); // <-- creates DB if not found ??

if( rc ){
    // failed
    fprintf(stderr, "ERROR: Can't open database: %s\n", sqlite3_errmsg(db));
} 

Answer 1

sqlite3_open returns an error if the database does not already exist. To create the database if it doesn’t already exist, use sqlite3_open_v2 with the SQLITE_OPEN_CREATE and SQLITE_OPEN_READWRITE flags (both are required):

rc = sqlite3_open_v2(/* DB Path */, &db, SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE, NULL);

Reference

---

To find /* DB PATH */, you need to base the filename off of the documents directory:

- (NSString *) applicationDocumentsDirectory 
{    
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *basePath = ([paths count] > 0) ? [paths objectAtIndex:0] : nil;
    return basePath;
}

You can use this convenience method to combine the documents path with the database name:

NSString *documents = [self applicationDocumentsDirectory];
NSString *dbPath = [documents stringByAppendingPathComponent:@"test.db"];

rc = sqlite3_open_v2([dbPath UTF8String], &db, SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE, NULL);