Exception while reading an empty table

Question

Iam trying to read data from a table. Initially it is empty. If i tried to read at that time it will cause an exception. My code is given Below

-(NSMutableArray *) selectDataFrom:(NSString *) tableName
{   
    NSString *qsql = [NSString stringWithFormat:@"SELECT * FROM '%@' ",tableName];  
    sqlite3_stmt *statement;
    if (sqlite3_prepare_v2( dataBase, [qsql UTF8String], -1, &statement, nil) == SQLITE_OK)
    {
        NSLog(@"INSIDE IF");                    
        while (sqlite3_step(statement) == SQLITE_ROW) 
        {
            NSLog(@"INSIDE WHILE");         
            // my code
        }
    }
    return allData; 
}

The first NSLog("INDISE IF"); is printed. But the second one is not printing.

Mention some books to learn sqlite3 statements of iPhone [ eg: sqlite_prepare_v2();] not SQL

[ Sorry for my poor English]

THIS IS THE FULL CODE

-(NSMutableArray *) selectDataFrom:(NSString *) tableName
{

    allData = [[NSMutableArray alloc] init];
    NSString *qsql = [NSString stringWithFormat:@"SELECT * FROM '%@' ",tableName];
    sqlite3_stmt *statement;

    if (sqlite3_prepare_v2( dataBase, [qsql UTF8String], -1, &statement, nil) == SQLITE_OK)
    {       


        while (sqlite3_step(statement) == SQLITE_ROW) 
        {
            NSLog(@"REACHED 1");            
            myProgram = [[Programs alloc] init];    

            char *date  = (char *) sqlite3_column_text(statement, 0);
            myProgram.nss_Date = [[NSString alloc] initWithUTF8String:date];            

            char *type  = (char *) sqlite3_column_text(statement, 3);
            myProgram.nss_Type = [[NSString alloc]initWithUTF8String:type];

            [nsma_allDonorsMA addObject:d_OneDonor];        
        }
    }
    else {
        //      NSLog(@"failed to select data");

    }
    return allData;
}

This is the exception: *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSMutableArray objectAtIndex:]: index 0 beyond bounds for empty array' *** Call stack at first throw: — new_programmer
– new_programmer, Commented Sep 9, 2010 at 23:37
What happens where you typed // my code? Since you’re not doing anything with an NSMutableArray in the code you showed we can’t say what you did wrong with it. — anon
– anon, Commented Sep 9, 2010 at 23:44
Sven, The problem is when selecting an empty table. When i tried to read a non-empty table , there is no problem. — new_programmer
– new_programmer, Commented Sep 11, 2010 at 16:47

Stefan Arentz · Accepted Answer · 2010-09-10 00:45:55Z

1

Try enabled breakpoints on exceptions and run your app in the debugger. It will show you exactly where you are calling objectAtIndex:. (It is not in the above code)

answered Sep 10, 2010 at 0:45

Stefan Arentz

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1 Comment

new_programmer Over a year ago

Thank you St3fan, I did as you told. I found the reason for exception.

AechoLiu · Accepted Answer · 2010-09-10 00:45:13Z

0

Where is your sqlite3_finalize() ??

You should release sqlite3_stmt structure in your sqlite3_prepare_v2 block, as following.

sqlite3_stmt *sql_stmt; 
if (sqlite3_prepare_v2(...) == SQLITE_OK)
{
    ....

    sqlite3_finalize(sql_stmt);
}

answered Sep 10, 2010 at 0:45

AechoLiu

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1 Comment

new_programmer Over a year ago

Thank you Toro for your reply

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