I have the following Model Relationship
Models
Sector - [id, name]
Location - [id, sector_id, name]
Sector has many locations
Location belongs to sector
class Location extends Model {
public function sector() {
return $this->belongsTo('App\Sector');
}
}
I want to make the following query using Laravel 5 Eloquent
SELECT * FROM locations WHERE sector_id IN (1,2,3)
I tried,
$location->where('sector_id', 'in', [1,2,3])
But no any records were returned.
You should use whereIn method and use the get method at the end to actually fetch the objects from DB, like this:
$locations = App\Location::whereIn('sector_id', [1,2,3])->get();
Related
I have the following tables in my database:
- Reservation
- TrainStation
- Train
- Traveller
- Reservation_Traveller
- TrainSeats: Attributes are: Train_Id, Seat, Traveller_Id
I want to find the TrainSeats rows of a particular Reservation
I have a Reservation object that contains an ICollection<Traveller> property containing the travellers of which I want to remove their seats from the TrainSeats table. I fetched the reservation object from the database like this:
var reservation = db.Reservation.Where(r => r.Id == id).FirstOrDefault();
So I want to do something like this:
db.TrainSeats.Where(ts => ts.Traveller_Id IN reservation.Travellers)
First select the travelers id:
var ids=reservation.Travellers.Select(e=>e.Id);
Then use Contains extension method which is translated into IN in sql:
var query=db.TrainSeats.Where(ts => ids.Contains(ts.Traveller_Id));
I guess if you use the FK property and navigation properties you can do it in one query:
var query= db.Travellers.Where(e=>e.ReservationId==id).SelectMany(t=>t.TrainSeats);
I am a newbie to Laravel 5.2 and am working on a legacy system and am a bit confused regarding eloquent and would appreciate someone giving me the code.
There are 3 tables:
cards
categories
cards2cat
cards can be part many categories which are kept in cards2cat table.
The cards2cat table has the following structure
id (primary key)
image (card)
category
What I want to do is to have a method in the Cards model called something like getCardsWithCategores which returned the cards info plus the names of the categories from the category table.
The categories table has a key of id and a field category.
Thanks!
Go to your Card2Cats model and add this:
public function categories()
{
return $this->hasOne('App\Categories','id','category');
}
public function cards()
{
return $this->hasOne('App\Cards','id','image');
}
For the query you do this:
$cards = Card2Cat::with('categories','cards')->get();
foreach ($cards as $key => $value) {
echo $value->id.', Card:'.$value->cards->name.', Category:'.$value->categories->category.'<br>';
//$value->cards gives you all column of cards and you can do
//$value->cards->colName
// same goes for $value->categories
}
Make sure the spelling of your classes and table column names are correct before running the code :D
I am developing an application with Laravel 5, I have 2 tables product and Category, the producttable has a column category_id which refers to id of catgeory table
I also have 2 models Category and Product
Question:
I just need to add a simple function to my Category model which return the categories joined by products where the product.sx_code = 0 with eloquent
You can just add a normal relationship method and append a where condition:
public function specialProducts(){
return $this->hasMany('App\Product')->where('sx_code', 0);
}
Im trying to call a stored procedure using Entity framework.
If I go direcly to the web api method it works fine, but when calling it from breeze it causes an exception on the metadata method.
The error is :
"Could not find the CLR type for...".
Anyone know how to fix this?
I had the very same issue, but thank God I figured out a solution. Instead of using a stored procedure, you should use a view, as Breeze recognizes views as DbSet<T>, just like tables. Say you have a SQL server table that contains two tables Customers and Orders.
Customers (**CustomerId**, FirstName, LastName)
Orders (OrderId, #CustomerId, OrderDate, OrderTotal)
Now, say you want a query that returns orders by CustomerId. Usually, you would do that in a stored procedure, but as I said, you need to use a view instead. So the query will look like this in the view.
Select o.OrderId, c.CustomerId, o.OrderDate, o.OrderTotal
from dbo.Orders o inner join dbo.Customers c on c.CustomerId = o.CustomerId
Notice there is no filtering (where ...). So:
i. Create a [general] view that includes the filtering key(s) and name it, say, OrdersByCustomers
ii. Add the OrdersByCustomers view to the entity model in your VS project
iii. Add the entity to the Breeze controller, as such:
public IQueryable<OrdersByCustomers> OrdersByCustomerId(int id)
{
return _contextProvider.Context.OrdersByCustomers
.Where(r => r.CustomerId == id);
}
Notice the .Where(r => r.CustomerId == id) filter. We could do it in the data service file, but because we want the user to see only his personal data, we need to filter from the server so it only returns his data.
iv. Now, that the entity is set in the controller, you may invoke it in the data service file, as such:
var getOrdersByCustomerId = function(orderObservable, id)
{
var query = breeze.EntityQuery.from('OrdersByCustomerId')
.WithParameters({ CustomerId: id });
return manager.executeQuery(query)
.then(function(data) {
if (orderObservable) orderObservable(data.results);
}
.fail(function(e) {
logError('Retrieve Data Failed');
}
}
v. You probably know what to do next from here.
Hope it helps.
I have a statement:
var items = from e in db.Elements
join a in db.LookUp
on e.ID equals a.ElementID
where e.Something == something
select new Element
{
ID = e.ID,
LookUpID = a.ID
// some other data get populated here as well
};
As you can see, all I need is a collection of Element objects with data from both tables - Elements and LookUp. This works fine. But then I need to know the number of elements selected:
int count = items.Count();
... this call throws System.NotSupportedException:
"The entity or complex type 'Database.Element' cannot be constructed in a LINQ to Entities query."
How am I supposed to select values from multiple tables into one object in Entity Framework? Thanks for any help!
You are not allowed to create an Entity class in your projection, you have to either project to a new class or an anonymous type
select new
{
ID = e.ID,
LookUpID = a.ID
// some other data get populated here as well
};
Your code doesn't work at all. The part you think worked has never been executed. The first time you executed it was when you called Count.
As exception says you cannot construct mapped entity in projection. Projection can be made only to anonymous or non mapped types. Also it is not clear why you even need this. If your class is correctly mapped you should simply call:
var items = from e in db.Elements
where e.Something == something
select e;
If LookupID is mapped property of your Element class it will be filled. If it is not mapped property you will not be able to load it with single query to Element.