Question

I am trying to read from a database file (performing a simple select all functions).

I am using FMDB.

Here’s how i created the DB;

Pro:~ dd$ sqlite3 db.db
SQLite version 3.7.7 2011-06-25 16:35:41
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> create table cus(id integer primary key, firstname varchar(30));
sqlite> inser into cus(firstname)values('f');
Error: near "inser": syntax error
sqlite> insert into cus(firstname)values('f');
sqlite> select * from cus;
1|f
sqlite> 

I copied the file (db.db) to my resource folder in xCode. changed the name of the db file to db.db in the app delegate. Code for my program is exactly yhe same as this tutorial.

Here’s the code ;

-(NSMutableArray *) getCustomers
{
    NSMutableArray *customers = [[NSMutableArray alloc] init];


    NSString * path = [(AppDelegate*)[[UIApplication sharedApplication]delegate]databasePath];
    NSLog(@"DB path %@ ",path);
    FMDatabase *db = [FMDatabase databaseWithPath:path];

    [db open];

    FMResultSet *results = [db executeQuery:@"SELECT * FROM cus"];
     NSLog(@"result %@ ",results);
    while([results next]) 
    {
        NSLog(@"result %@ ",results);
        Customer *customer = [[Customer alloc] init];

        customer.customerId = [results intForColumn:@"id"];
        customer.firstName = [results stringForColumn:@"firstname"];

        [customers addObject:customer];

    }

    [db close];

    return customers; 

}

My problem;

Eventhough there is 1 record in the DB, the result of the Select statement is NULL. Why is this and how can i correct it ?

Answer 1

Assuming that the database was created and imported into the project successfully, try the following:

-(NSMutableArray *) getCustomers
{
 NSMutableArray *customers = [[NSMutableArray alloc] init];
 NSString * path = [(AppDelegate*)[[UIApplication sharedApplication]delegate]databasePath];
 NSLog(@"DB path %@ ",path);
 FMDatabase *db = [FMDatabase databaseWithPath:path];

 if(![db open])
 {
   NSLog(@"Could not open DB, try again");
   return nil;
 }

 FMResultSet *results = nil;
 results = [db executeQuery:@"SELECT * FROM cus"];
 NSLog(@"result %@ ",results);
 while([results next]) 
 {
   Customer *customer = [[Customer alloc] init];

   customer.customerId = [results intForColumn:@"id"];
   customer.firstName = [results stringForColumn:@"firstname"];

   NSLog(@"Customer object %@", customer);
   [customers addObject:customer];
   [customer release];
 }

 [db close];

 return customers; 
}