Xcode - NSInvalidArgumentException', reason: '*** +[NSString stringWithUTF8String:]: NULL cString' - objective-c

Question

I have the below code that should populate the TableViewController with information from my sqlite file, it lets me add fine, and i can view the file and the information is there, but I'm getting the above error message, and failing miserably at fixing it....
-(NSMutableArray *) stockList
{
NSString *filePath = [self getWritableDBPath];
if(sqlite3_open([filePath UTF8String], &db) == SQLITE_OK)
{
const char *sql = "Select Description, Quantity from StockTable";
sqlite3_stmt *sqlStatement;
if(sqlite3_prepare(db, sql, -1, &sqlStatement, NULL) != SQLITE_OK)
{
NSLog(#"Problem with query: %s", sqlite3_errmsg(db));
}
else
{
while (sqlite3_step(sqlStatement)==SQLITE_ROW)
{
Stock * stock = [[Stock alloc] init];
stock.desc = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, 1)];
stock.qty = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, 2)];
[thestock addObject:stock];
stock = nil;
}
}
sqlite3_finalize(sqlStatement);
}
sqlite3_close(db);
return thestock;
}
thanks for any help, currently googling it myself..
connection strings as mentioned below: (reason being it causes a LINK error and states that MyDB is a duplicate in both views)
TableView:
NSString * MyDB2=#"StockDatabase.db";
AddingView:
NSString * MyDB=#"StockDatabase.db";

Answer 1

One (or both) of the columns you are fetching from the database is NULL:
stock.desc = [NSString stringWithUTF8String:(char *)sqlite3_column_text(sqlStatement, 1)];
stock.qty = [NSString stringWithUTF8String:(char *)sqlite3_column_text(sqlStatement, 2)];
Guard against that with:
const char *desc = sqlite3_column_text(sqlStatement, 1);
if (desc)
stock.desk = #(desc);
const char *qty = sqlite3_column_text(sqlStatement, 2);
if (qty)
stock.qty = #(qty);

Answer 2

I got this error too. How I solved it is by setting the first column text index to "0" instead of "1". And the error went away.
char *charPrice = (char*) sqlite3_column_text(stmt, 0);
NSString *price = [NSString stringWithUTF8String:charPrice];
char *charName = (char*) sqlite3_column_text(stmt, 1);
NSString *name = [NSString stringWithUTF8String:charName];