Load column form parse in to an Array - ios

I am working on a little app with parse.com. I want to download all objects from a column (Array) called "Firstname". I found some code, but when I log "object" it shows the class completely:
PFQuery *query = [PFQuery queryWithClassName:#"Name"];
[query selectKeys:#[#"Firstname"]];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
NSLog("%#", objects);
}];
Edit:
PFQuery *query = [PFQuery queryWithClassName:#"Name"];
[query selectKeys:#[#"Firstname"]];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
self.FirstnameArray = [objects valueForKey:#"Firstname"];
NSLog(#"%#", self.FirstnameArray);
[self.myTableView reloadData];
}];

A query always returns objects of the class associated with the query. Using selectKeys just limits the data that comes back.
You can extract an array of just the values from the returned array with:
NSArray *values = [objects valueForKey:#"Firstname"]

Thats normal, you will get back the whole object - aka a row from that class you are performing the query on. If I recall correct, SelectKey will return any associated object - ie a relation object. So in your case you do not need to use select.

Related

sort the query depends on the data in an array

In one condition, sort the query depends on the objectId in the array.If the objectId is in the arraym, i want show it top.My code
PFQuery *query = [PFQuery queryWithClassName:#"Group"];
[query orderByDescending:#"pinUser" ]; //Normal Sort
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
------
---------
}
}];
I want to change the change the normal sort to my requirement.
Apply your sorting on resulted objects in block. u can check the objectId of objects in ur arrayM or not on resulted array of objects , not with PFQuery

IOS Parse how do I retrieving objects from a query based on two classes?

I have two classes User and Post. The User class has a userType field and I want to retrieve all of the posts from a given userType lets call them group x. In the Post class I have a pointer to the User class.
I was trying to do something like, first retrieve all user Ids for the type of user I want:
PFQuery *queryUser = [PFQuery queryWithClassName:kFTUserClassKey];
[queryUser whereKey:kFTUserTypeKey equalTo:kFTUserTypeX];
[queryUser whereKey:kFTUserLocationKey nearGeoPoint:nearGeoPoint withinMiles:miles];
[queryUser findObjectsInBackgroundWithBlock:^(NSArray *usersTypeX, NSError *error) {
if (!error) {
NSMutableArray *objectIds = [[NSMutableArray alloc] init];
// Add ambassador ids into query
for (PFObject *userX in usersTypeX) {
[objectIds addObject:[PFObject objectWithoutDataWithClassName:kFTUserClassName objectId: userX.objectId]];
}
}
}];
And then I wanted to query based on these objectIds but I am not sure how to query on this array or if this is even the correct way to do this. How can this be done?
Parse provides a matchesQuery method on query, so ...
PFQuery *innerQuery = [PFQuery queryWithClassName:#"User"];
[innerQuery whereKey:#"userType" equalTo:#"X"]; // fix with your real user type
PFQuery *query = [PFQuery queryWithClassName:#"Post"];
[query whereKey:#"user" matchesQuery:innerQuery];
[query findObjectsInBackgroundWithBlock:^(NSArray *posts, NSError *error) {
// posts are posts where post.user.userType == X
}];

iOS Parse SDK: Multiple query results put into an Array

Scenario = I have an app where users can send each other Messages, Comments, and Pokes that are queried to populate the current user's notificationsTableView. There are 3 queries that must take place, one for Messages, two for Comments, and three for Pokes. The code I'm using is below...
PFQuery *messageQuery = [PFQuery queryWithClassName:#"Message"];
[messageQuery whereKey:#"receiverID" equalTo:[PFUser currentUser][#"userID"]];
[messageQuery orderByDescending:#"createdAt"];
[messageQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
messages = objects;
}];
PFQuery *pokeQuery = [PFQuery queryWithClassName:#"Poke"];
[pokeQuery whereKey:#"receiverID" equalTo:[PFUser currentUser][#"userID"]];
[pokeQuery orderByDescending:#"createdAt"];
[pokeQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
pokes = objects;
}];
PFQuery *commentsQuery = [PFQuery queryWithClassName:#"Comment"];
[commentsQuery whereKey:#"receiverID" equalTo:[PFUser currentUser][#"userID"]];
[commentsQuery orderByDescending:#"createdAt"];
[commentsQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
comments = objects;
}];
What is desired = To consolidate the following arrays: "messages", "pokes", and "comments" into a single array (notificationsArray) that I can sort by "createdAt" and populate my notificationsTableView with notificationsArray objectAtIndexPath:indexPath.row.
Problems I have encountered = (there are two)
(1) When I NSLog the results of any of these queries like so...
PFQuery *messageQuery = [PFQuery queryWithClassName:#"Message"];
[messageQuery whereKey:#"receiverID" equalTo:[PFUser currentUser][#"userID"]];
[messageQuery orderByDescending:#"createdAt"];
[messageQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
messages = objects;
}];
NSLog(#"messages = %#", messages);
It logs "messages = (null)". I can not for the life of me figure out why it is not being set. I know there are messages because when I NSLog the "objects" Array that comes from the query it gives me what I want. It's like the contents of the query will not leave the scope of the query itself. All of the queries above do this. If I can not get the contents of the query out of that block then I can not create an array of all of the arrays to populate the notificationsTableView with, so I'm screwed. Please help.
(2) Even if I do get the results from the queries into individual arrays, I am not sure how to create an array of arrays and order them by a key. Can anyone help me with this? Please.
You are probably looking for the +orQueryWithSubqueries:(NSArray *)queries method, but I don't understand what the return value description is:
a PFQuery that is the or of the passed in PFQueries
I'm thinking this means || (or) ?
You would do it like this:
NSArray *queryArray = [NSArray arrayWithObjects:messageQuery,pokeQuery,commentsQuery,nil];
PFQuery *allQueries = [PFQuery orQueryWithSubqueries:queryArray];
[allQueries findObjects... {
As for the second error, you are right, value is not retained because when the block loses scope all of the local variables inside get destroyed in the autoreleasepool. You need to retain this by using a strong property. self.messages = objects;
(1) You are logging messages outside of the callback function, and the log comes before the callback function returned. Try to log messages into your callback, just after assigning it.
[messageQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
messages = objects;
NSLog(#"messages = %#", messages)
}];
(2) Before sorting, create a NSMutableArray and use the addObjectsFromArray: method with each retrieved array.
To sort notifications, you should use a NSSortDescriptor, which is a mechanism that describes how to sort an array according to the format of contained objects. Here's an example that could match your needs:
NSSortDescriptor *createdAtDescriptor = [[NSSortDescriptor alloc] initWithKey:#"createdAt" ascending:YES];
notificationsArray = [messages sortedArrayUsingDescriptors:#[createdAtDescriptor]];
Hope this help!
EDIT: you can embed your temporary NSMutableArray into an autorelease pool to avoid useless memory leaks, so that the dedicated memory is freed just after you proceed to display.
EDIT: you can use orQueryWithSubqueries Parse method to merge several requests into a single one. It's not annoying in your case cause you're sorting PFObject according to their createdAt key, which is common to every PFObject. In any case, you will have to check PFObject types to display them according to their type. Please see full documentation here. Does not work for queries returning several kind of objects!

Query on Parse relational data is not coming back ordered using orderedByAscending

I'm querying relation data on parse and I would like the objects to come back ordered by the date they were created. I've had this method work before but haven't been able to get an ordered query using relational data. The query return is in a random order. Thanks in advance! Here's my code:
PFQuery *postQuery = [PFQuery queryWithClassName:#"Post"];
[roomQuery whereKey:#"name" equalTo:self.postName];
NSError *error;
//done on main thread to have data for next query
NSArray *results = [postQuery findObjects:&error];
PFObject *post;
if ([results count]) {
post = [results objectAtIndex:0];
NSLog(#"results were found");
} else {
NSLog(#"results were not found");
}
PFRelation *commentsRelation = [#"Comments"];
[commentsRelation.query orderByAscending:#"createdAt"];
[commentsRelation.query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (error) {
NSLog(#"Error Fetching Comments: %#", error);
} else {
NSArray *comments = objects;
}
I'm a little confused by your code,
you create a "postQuery", and call it, but never use any of its data.
There's also a roomQuery that never seems to have been allocated, or used.
You're querying a specific post by its name. Are you controlling its name? If not, you should use id's
what is PFRelation commentsRelation = [#"Comments"];
Probably because it's just a snippet, this stuff is dealt with elsewhere; however, for my answer, I'm assuming that your "comments" field is an array of "Comment" class objects.
Option 1:
PFQuery * postQuery = [PFQuery queryWithClassName:#"Post"];
[postQuery whereKey:#"name" equalTo:self.postName];
// again, possibly an id field would be more reliable
// [postQuery whereKey:#"objectId" equalTo:self.postId];
[postQuery includeKey:#"Comments"];
PFObject * post = [postQuery getFirstObject];// no need to download all if you just want object at [0]
// this will contain your post and all of it's comments with only one api call
// unfortunately, it's not sorted, so you would have to run a sort.
NSArray * comments = [post[#"Comments"] sortedArrayUsingComparator: ^(id obj1, id obj2) {
return [obj1[#"createdAt" compare: obj2[#"createdAt"];
}];
Option 2:
Perhaps a better option is to rework your data structure and instead of associating the comments to the post, you could associate the post to the comments (as in the parse docs)
PFQuery * postQuery = [PFQuery queryWithClassName:#"Post"];
[postQuery whereKey:#"name" equalTo:self.postName];
// again, possibly an id field would be more reliable
// [postQuery whereKey:#"objectId" equalTo:self.postId];
PFQuery * commentQuery = [PFQuery queryWithClassName:#"Comment"];
[commentsQuery whereKey:#"parent" matchesQuery:postQuery]; // when creating a comment, set your post as its parent
[commentsQuery addOrderDescending:#"createdAt"]
[commentQuery findObjectsInBackgroundWithBlock:^(NSArray *comments, NSError *error) {
// comments now contains the comments for myPost
}];
Both of the above solutions avoid making extra unnecessary api calls (parse charges based on calls after all!).

How to fetch all values for a single key from Parse.com

I'm trying to fetch all the names from my PeopleName class from Parse. It's not showing any build error, but I get a runtime error Error: field Name cannot be included because it is not a pointer to another object (Code: 102, Version: 1.2.17).
Here is code. Any help?
PFQuery *query = [PFQuery queryWithClassName:#"PeopleNames"];
[query includeKey:#"Name"];
[query selectKeys:#[#"Name"]];
[query findObjectsInBackgroundWithBlock:^(NSArray *results, NSError *error) {
for (PFObject *object in results) {
[self.boyNames addObject:[object objectForKey:#"Name"]];
}
}];
[query selectKeys:#[#"Name"]]; is correct to limit the returned data to only the names. [query includeKey:#"Name"]; is not required as it is the way to include the destination objects at the other end of a relationship (which you don't have).
So, keep [query selectKeys:#[#"Name"]]; and remove [query includeKey:#"Name"]; and you'll get what you want.

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