iphone - Unable to retrieve and view results from a SQLite database -

dear fellow iphone , objective-c developers:

i trying build skills iphone developer, , presently working on using sqlite database. have created sqlite table follows in grocerylistappdelegate.m class:

- (void)applicationdidfinishlaunching:(uiapplication *)application {          self.database = [[[isdatabase alloc] initwithfilename:@"testdb.sqlite"] autorelease];  if(![[database tablenames] containsobject:@"groceryitem"]) {      [database executesql:@"create table groceryitem(primarykey integer primary key autoincrement, name text not null, number integer not null)"];     [database executesql:@"insert groceryitem (name, number) values ('apples', 5)"];     [database executesql:@"insert groceryitem (name, number) values ('oranges', 3)"];  }  [window addsubview:navigationcontroller.view]; [window makekeyandvisible]; 

}

i make sql call in rootviewcontroller.m class:

- (void)viewdidload { [super viewdidload];  grocerylist1appdelegate *appdelegate = (grocerylist1appdelegate *)[[uiapplication sharedapplication] delegate];  self.results = [appdelegate.database executesqlwithparameters:@"select * groceryitem number < ?", [nsnumber numberwithint:6], nil]; 

}

my executesqlwithparameters() method looks this:

- (nsarray *) executesql:(nsstring *)sql withparameters: (nsarray *) parameters {  nsmutabledictionary *queryinfo = [nsmutabledictionary dictionary]; [queryinfo setobject:sql forkey:@"sql"];  if (parameters == nil) {      parameters = [nsarray array];  }  //we add parameters queryinfo  [queryinfo setobject:parameters forkey:@"parameters"];  nsmutablearray *rows = [nsmutablearray array];  //log parameters  if (logging) {      nslog(@"sql: %@ \n parameters: %@", sql, parameters);  }  sqlite3_stmt *statement = nil;  if (sqlite3_prepare_v2(database, [sql utf8string], -1, &statement, null) == sqlite_ok) {      [self bindarguments: parameters tostatement: statement queryinfo: queryinfo];      bool needstofetchcolumntypesandnames = yes;     nsarray *columntypes = nil;     nsarray *columnnames = nil;      while (sqlite3_step(statement) == sqlite_row) {          if (needstofetchcolumntypesandnames) {              columntypes = [self columntypesforstatement:statement];             columnnames = [self columnnamesforstatement:statement];             needstofetchcolumntypesandnames = no;          }          id row = [[nsmutabledictionary alloc] init];         [self copyvaluesfromstatement:statement torow:row queryinfo:queryinfo columntypes:columntypes columnnames:columnnames];         [rows addobject:row];         [row release];      }         }  else {      sqlite3_finalize(statement);     [self raisesqliteexception:[[nsstring stringwithformat:@"failed execute statement: '%@', parameters: '%@' message: ", sql, parameters] stringbyappendingstring:@"%s"]];  }  sqlite3_finalize(statement); return rows; 

}

when build , run code, no results, when in fact, given sql call, should apples, , oranges in list. however, when modify sql code this:

self.results = [appdelegate.database executesql:@"select * groceryitem"]; 

which calls different method: executesql():

- (nsarray *) executesql: (nsstring *)sql {  return [self executesql:sql withparameters: nil]; 

}

in case, end getting results: apples, , oranges. why this? doing wrong? why getting results 1 sql call, , not another?

any appreciated.

if extract .sqlite file simulator or device , open in on command line using sqlite3, query work? enable separate testing database creation code , query code.