This question is related to Parse.com
I want to build a push query to push a notification from cloud code to all users belonging to 'Moderator' role.
I tried below code, it failed to push as "users" is a relation, not an object.
var moderatorQuery = new Parse.Query(Parse.Role);
moderatorQuery.equalTo("name", "Moderators");
// Push to devices belonging to these moderators
var pushQuery = new Parse.Query(Parse.Installation);
pushQuery.matchesKeyInQuery("installationOwner", "users", moderatorQuery);
Another way of doing this is by fetching the Moderator role object and using the relation.query() or by calling getUsers() on moderator object.
But my requirement is to push to a query directly without fetching(get/find) any object.
How to build such a query ?
I think you need first to get the role, then use it's user relation query as the query to match in the pushQuery, like this:
var moderatorQuery = new Parse.Query(Parse.Role);
moderatorQuery.equalTo("name", "Moderators");
moderatorQuery.first().then(function(moderatorRole) {
var pushQuery = new Parse.Query(Parse.Installation);
var usersQuery = moderatorRole.relation("users").query();
pushQuery.matchesQuery("installationOwner", usersQuery);
// setup push, then send()
});
EDIT - Missed the last sentence of the question. The short answer is that there's no way to query the "many" side of the relationship in a single query.
The longer answer is that it can be done with additional data. You can make the query singular at the cost of keeping additional data up-to-date.
For example, you could keep an (a) isModerator bool on the User, or (b) more generally, a "roles" array of pointers (not a relation, because that's your root problem) on User, or (c) a separate table altogether that joins Role and User with singular pointers.
All of these ideas make the single-query easy (a) query User where isModerator == true, (b) query User where roles isEqual to moderator, (c) query TheJoinTable where role == moderator, include user and select user.
Doing this shifts the burden from the query to keeping the extra data up to date. You could accomplish this pretty simply using beforeSave on either end of the Role-User relation (probably Role).
All that said, you should examine the added constraint of a single query very carefully and make sure its worth the extra trouble.
Related
I'm working on my first laravel project: a family tree. I have 4 branches of the family, each with people/families/images/stories/etc. A given user on the website will have access to everything for 1, 2, or 4 of these branches of the family (I don't want to show a cousin stuff for people they're not related to).
So on various pages I want the collections from the controller to contain stuff based on the given user's permissions. Merge seems like the right way to do this.
I have scopes to get people from each branch of the family, and in the following example I also have a scope for people with a birthday this month. In order to show the right set of birthdays for this user, I can get this by merging each group individually if they have access.
Here's what my function would look like if I showed everyone in all 4 family branches:
public function get_birthday_people()
{
$user = \Auth::user();
$jones_birthdays = Person::birthdays()->jones()->get();
$smith_birthdays = Person::birthdays()->smith()->get();
$lee_birthdays = Person::birthdays()->lee()->get();
$brandt_birthdays = Person::birthdays()->brandt()->get();
$birthday_people = $jones_birthdays
->merge($smith_birthdays)
->merge($lee_birthdays )
->merge($brandt_birthdays );
return $birthday_people;
My challenge: I'd like to modify it so that I check the user's access and only add each group of people accordingly. I'm imagining something where it's all the same as above except I add conditionals like this:
if($user->jones_access) {
$jones_birthdays = Person::birthdays()->jones()->get();
}
else{
$jones_birthdays =NULL;
}
But that throws an error for users without access because I can't call merge on NULL (or an empty array, or the other versions of 'nothing' that I tried).
What's a good way to do something like this?
if($user->jones_access) {
$jones_birthdays = Person::birthdays()->jones()->get();
}
else{
$jones_birthdays = new Collection;
}
Better yet, do the merge in the condition, no else required.
$birthday_people = new Collection;
if($user->jones_access) {
$birthday_people->merge(Person::birthdays()->jones()->get());
}
You are going to want your Eloquent query to only return the relevant data for the user requesting it. It doesn't make sense to query Lee birthdays when a Jones person is accessing that page.
So what you will wind up doing is something like
$birthdays = App\Person::where('family', $user->family)->get();
This pulls in Persons where their family property is equal to the family of the current user.
This probably does not match the way you have your relationships right now, but hopefully it will get you on the right track to getting them sorted out.
If you really want to go ahead with a bunch of queries and checking for authorization, read up on the authorization features of Laravel. It will give let you assign abilities to users and check them easily.
Time to leave the shy mode behind and make my first post on stackoverflow.
After doing loads of research (plugins, performance, indexes, types of update, friends) and after trying several approaches I was unable to find a proper answer/solution.
So if possible I would like to get your feedback/help in a Microsoft Dynamics CRM 2013/2015 plugin performance issue (or coding technique)
Scenario:
Microsoft Dynamics CRM 2013/2015
2 Entities with Relationship 1:N
EntityA
EntityB
EntityB has the following columns:
Id | EntityAId | ColumnDemoX (decimal) | ColumnDemoY (currency)
Entity A has: 500 records
Entity B has: 150 records per each Entity A record. So 500*150 = 75000 records.
Objective:
Create a Post Entity A Plugin Update to "mimic" the following SQL command
Update EntityB
Set ColumnDemoX = (some quantity), ColumnDemoY = (some quantity) * (some value)
Where EntityAId = (some id)
One approach could be:
using (var serviceContext = new XrmServiceContext(service))
{
var query = from a in serviceContext.EntityASet
where a.EntityAId.Equals(someId)
select a;
foreach (EntityA entA in query)
{
entA.ColumnDemoX = (some quantity);
serviceContext.UpdateObject(entA);
}
serviceContext.SaveChanges();
}
Problem:
The foreach for 150 records in the post plugin update will take 20 secs or more.
While the
Update EntityB Set ColumnDemoX = (some quantity), ColumnDemoY = (some quantity) * (some value) Where EntityAId = (some id)
it will take 0.00001 secs
Any suggestion/solution?
Thank you all for reading.
H
You can use the ExecuteMultipleRequest, when you iterate the 150 entities, save the entities you need to update and after that call the request. If you do this, you only call the service once, that's very good for the perfomance.
If your process could be bigger and bigger, then you should think making it asynchronous as a plug-in or a custom activity workflow.
This is an example:
// Create an ExecuteMultipleRequest object.
requestWithResults = new ExecuteMultipleRequest()
{
// Assign settings that define execution behavior: continue on error, return responses.
Settings = new ExecuteMultipleSettings()
{
ContinueOnError = false,
ReturnResponses = true
},
// Create an empty organization request collection.
Requests = new OrganizationRequestCollection()
};
// Add a UpdateRequest for each entity to the request collection.
foreach (var entity in input.Entities)
{
UpdateRequest updateRequest = new UpdateRequest { Target = entity };
requestWithResults.Requests.Add(updateRequest);
}
// Execute all the requests in the request collection using a single web method call.
ExecuteMultipleResponse responseWithResults =
(ExecuteMultipleResponse)_serviceProxy.Execute(requestWithResults);
Few solutions comes to mind but I don't think they will please you...
Is this really a problem ? Yes it's slow and database update can be so much faster. However if you can have it as a background process (asynchronous), you'll have your numbers anyway. Is it really a "I need this numbers in the next second as soon as I click or business will go down" situation ?
It can be a reason to ditch 2013. In CRM 2015 you can use a calculated field. If you need this numbers only to show up in forms (eg. you don't use them in reporting), you could also do it in javascript.
Warning this is for the desesperate call. If you really need your update to be synchronous, immediate, you can't use calculated fields, you really know what your doing etc... Why not do it directly in the database? I know this is a very bad advice. There are a lot of reason not to do it this way (you can read a few here). It's unsupported and if you do something wrong it could go really bad. But if your real situation is as simple as your example (just a calculated field, no entity creation, no relation modification), you could do it this way. You'll have to consider many things: you won't have any audit on the fields, no security, caching issues, no modified by, etc. Actually I pretty much advise against this solution.
1 - Put it this logic to async workflow.
OR
2 - Don't use
serviceContext.UpdateObject(entA);
serviceContext.SaveChanges();.
Get all the records (150) from post stage update the fields and ExecuteMultipleRequest to update crm records in one time.
Don't send update request for each and every record
Why isn't the exception triggered? Linq's "Any()" is not considering the new entries?
MyContext db = new MyContext();
foreach (string email in {"asdf#gmail.com", "asdf#gmail.com"})
{
Person person = new Person();
person.Email = email;
if (db.Persons.Any(p => p.Email.Equals(email))
{
throw new Exception("Email already used!");
}
db.Persons.Add(person);
}
db.SaveChanges()
Shouldn't the exception be triggered on the second iteration?
The previous code is adapted for the question, but the real scenario is the following:
I receive an excel of persons and I iterate over it adding every row as a person to db.Persons, checking their emails aren't already used in the db. The problem is when there are repeated emails in the worksheet itself (two rows with the same email)
Yes - queries (by design) are only computed against the data source. If you want to query in-memory items you can also query the Local store:
if (db.Persons.Any(p => p.Email.Equals(email) ||
db.Persons.Local.Any(p => p.Email.Equals(email) )
However - since YOU are in control of what's added to the store wouldn't it make sense to check for duplicates in your code instead of in EF? Or is this just a contrived example?
Also, throwing an exception for an already existing item seems like a poor design as well - exceptions can be expensive, and if the client does not know to catch them (and in this case compare the message of the exception) they can cause the entire program to terminate unexpectedly.
A call to db.Persons will always trigger a database query, but those new Persons are not yet persisted to the database.
I imagine if you look at the data in debug, you'll see that the new person isn't there on the second iteration. If you were to set MyContext db = new MyContext() again, it would be, but you wouldn't do that in a real situation.
What is the actual use case you need to solve? This example doesn't seem like it would happen in a real situation.
If you're comparing against the db, your code should work. If you need to prevent dups being entered, it should happen elsewhere - on the client or checking the C# collection before you start writing it to the db.
I have a bunch of custom entity records in a List (which comes from a csv file).
What is the best way to check which records are new and create those that are?
The equality check is based on a single text field in this case, but I need to do the same thing elsewhere where the equality check is based on a lookup and 2 text fields.
For arguments sake lets say I was inserting Account records, this is what I currently have:
private void CreateAccounts()
{
var list = this.GetAccounts(); // get the list of Accounts, some may be new
IEnumerable<string> existingAccounts = linq.AccountSet.Select(account => account.AccountNumber); // get all Account numbers in CRM, linq is a serviceContextName variable
var newAccounts = list.Where(account => !existingAccounts.Contains(account.AccountNumber)); // Account numbers not in CRM
foreach (var accountNumber in newAccounts) // go through the new list again and get all the Account info
{
var account = newAccounts.Where(newAccount => newAccount.AccountNumber.Equals(accountNumber)).FirstOrDefault();
service.Create(account);
}
}
Is there a better way to do this?
I seem to be iterating through lists too many times, but it must be better than querying CRM multiple times:
foreach (var account in list)
{
// is this Account already in CRM
// if not create the Account
}
Your current method seems a bit backwards (get everything out of CRM, then compare it to what you have locally), but it may not be too bad depending on how many accounts you have ie < 5000.
For your simple example, you should be able to apply a where in statement.
Joining on multiple fields is a little more tricky. If you are running CRM > R12, you should be able to use the ExecuteMultipleRequests, creating a seperate request for each item in your list, and then batching them all up, so there is one big request "over the wire" to CRM.
how can I build a table of "orders" containing "IdOrder", "Description" and "User"?... the "User" field is a reference to the table "Users", which has "IdUser" and "Name". I'm using repositories.
I have this repository:
Repository<Orders> ordersRepo = new OrderRepo<Orders>(unitOfWork.Session);
to return all Orders to View, I just do:
return View(ordersRepo.All());
But this will result in something like:
IdOrder:1 -- Description: SomeTest -- User: UserProxy123ih12i3123ih12i3uh123
-
When the expected result was:
IdOrder:1 -- Description: SomeTest -- User: Thiago.
PS: I don't know why it returns this "UserProxy123ih12i3123ih12i3uh123". In Db there is a valid value.
The View:
It is showed in a foreach (var item in Model).
#item.Description
#item.User //--> If it is #item.User.Name doesn't work.
What I have to do to put the Name on this list? May I have to do a query using LINQ - NHibernate?
Tks.
What type of ORM are you using? You mention "repositories" but does that mean LinqToSql, Entity Framework, NHibernate, or other?
It looks like you are getting an error because the User field is not loaded as part of the original query. This is likely done to reduce the size of the result set by excluding the related fields from the original query for Orders.
There are a couple of options to work around this:
Set up the repository (or context, depending on the ORM) to include the User property in the result set.
Explicitly load the User property before you access it. Note that this would be an additional round-trip to the database and should not be done in a loop.
In cases where you know that you need the User information it would make sense to ensure that this data in returned from the original query. If you are using LinqToSql take a look at the DataLoadOptions type. You can use this type to specify which relationships you want to retrieve with the query:
var options = new DataLoadOptions();
options.LoadWith<Orders>(o => o.User);
DataContext context = ...;
context.LoadOptions = options;
var query = from o in context.Orders
select o;
There should be similar methods to achive the same thing whatever ORM you are using.
In NHibernate you can do the following:
using (ISession session = SessionFactory.OpenSession())
{
var orders = session.Get<Order>(someId);
NHibernateUtil.Initialize(orders.User);
}
This will result in only two database trips (regardless of the number of orders returned). More information on this can be found here.
In asp.net MVC the foreign key doesn't work the way you are using it. I believe you have to set the user to a variable like this:
User user = #item.User;
Or you have to load the reference sometimes. I don't know why this is but in my experience if I put this line before doing something with a foreign key it works
#item.UserReference.load();
Maybe when you access item.User.Name the session is already closed so NHib cannot load appropriate user from the DB.
You can create some model and initialize it with proper values at the controller. Also you can disable lazy loading for Orders.User in your mapping.
But maybe it is an other problem. What do you have when accessing "#item.User.Name" from your View?