I have the following Database tables:
tour
idtour
other_columns
day
idday
other_columns
tour_has_day
idtour
idday
Each tour has many days, and the days can be used in other tours
So, in the Tour.php model I add this function:
function days () {
return $this->hasManyThrough('App\Day', 'App\Tour_has_day', 'idtour', 'idday');
}
It gives me the correct number of related days but all rows have the same content
I debug the query that it returns:
select
`day`.*,
`tour_has_day`.`idtour`
from `day`
inner join
`tour_has_day` on `tour_has_day`.`idtour` = `day`.`idday`
where
`tour_has_day`.`idtour` = '1'
And it returns
You'll need a many-to-many relation with a pivot table like the one you have for that. The has-many-through relation is for when you have a parent and a child, and the child is the parent of another child.
Related
I am developing a p2p app with laravel. I have two tables namely users and loans.
Firstly, a user can be a lender or borrower.
Then users can have multiple loans and multiple loans belong to multiple users.
Also, a loan can belong to one borrower and also to multiple lenders.
To explain it further, the loan record will be created by the borrower(or the user). Then the system will distribute the loan and assign it to multiple lenders.
Example: Let's say, one borrower wants a loan of 3000. Our system will distribute the loan as 2000 and 1000 (or 1500 and 1500, or 2500 and 500, etc.). Then assign it to two lenders.
Now it could be more lenders or bigger amounts.
So how can I define something like this with laravel eloquent?
Here's what I thought of till now.
Users and loans will have a many-to-many relationship.
Loans table will have a lender_data column which will be an array that contains lender_id and amount.
But I can't really figure out a way to fetch all the loans of a single lender. So how can I do that?
That's a lot of words. Thank you for reading.
First of all, this question is quite vague and doesn't show any code which I think all questions should. Its harder to answer questions like this that don't necessarily have predefined answers.
Personally, I'd look into intermediate table models:
https://laravel.com/docs/8.x/eloquent-relationships#defining-custom-intermediate-table-models
That way you can have a Lenders table, a Loan table, a Users table, and this "in between" table that could be something like a LoanAmount table. The LoanAmount table is mostly a pivot table (allowing the many to many relationship between Lenders and Loans), however it can also store data like:
loan_id lender_id amount
1 1 1000
1 2 1000
Then the loan table would just be
user_id amount
1 2000
So a User can have many Loans, but it's the Loans that can have many LoanAmounts.
I'd go with next:
class User extends Model
{
public function loans()
{
return $this->belongsToMany(Loan::class)->using(LoanUser::class)->withPivot(['amount', 'percentage']);
}
}
class Loan extends Model
{
public function users()
{
return $this->belongsToMany(User::class)->using(LoanUser::class)->withPivot(['amount', 'percentage']);
}
}
class LoanUser extends Pivot
{
protected $with = [
'landers',
];
public function landers()
{
return $this->belongsToMany(Lander::class)->withPivot(['percentage']);
}
}
class Lander extends Model
{
public function loanUsers()
{
return $this->belongsToMany(LoanUser::class)->withPivot(['percentage']);
}
}
In loan_user pivot table you should make field called percentage that will go to user from full amount. In second pivot between LoanUser and Lander lander_loan_user you should also need percentage field that you would assign to each lander_loan_user relation. It would be second pivot table data.
After you save loan_user data, you would need to attach landers to first pivot model (second pivot table doesn't require pivot model per description). Since there are eager loaded landers to pivot model, when you query some user and their loan
$user = User::where(['loan.amount' => 3000])->first();
$user->pivot->landers;// will get you related landers
You already have full amount in first pivot table and with percentage from same table you know how much user (borrower) gets and in pivot's relation to landers table you will know how much each lander gets from that loan.
It is like "T" relation where upper ends of 't' letter are Loan and User, that crossroad is LoanUser pivot and lower end (base) of the letter 't' are landers.
To avoid hard time as much as possible, keep up with eloquent's convention (check good practice here) and for example, instead of borrower_id call that loan_id, also pivot table to be loan_user (pay attention on pivot singular).
This was written from top of head and not tested but this is the idea/way how task can/should be finished.
I am new to DAX and PowerBI and have a problem to write DAX formulas for my case:
I have two tables: Assets and Tickets. Each have an Id, and the Assets have a ParentAssetId (can be 0 or None).
In a DAX expression: I would like to count (and list) all the tickets attached to an Asset and its children.
I tried this way but without success:
nbChildTickets =
VAR mykey =
SELECTEDVALUE ( Assets[AssetKey] )
VAR mypar =
SELECTEDVALUE ( Assets[ParentId] )
RETURN
CALCULATE(
COUNTX(Tickets, Tickets[TicketKey]),
FILTER(Tickets, RELATED(Assets[ParentId]) = mykey)
)
The Tables and the Canvas
It is the asset table which contains both the AssetKey and the ParentId colums.
Have any idea or tuto to do this ?
Thanks
A question, are these tables already related? In case they are, it seems that you wouldn't need a measure like that to get the count of # of tickets by asset and its parent. I would do it in the next two ways. Supposing you need it in a table:
Option 1.
Create a simple count measure to get the number of tickets in Tickets table, it could be something like Number of Tickets = COUNTROWS('Tickets')
Drag a table to the canvas.
Add to the table Assets and its children columns, finally add your new measure to the table
Option 2. In case each ticket has an ID.
Drag a table to the canvas.
Add to the table Assets and its children columns. Also add your tickets Id.
At Fields section (where you drag and drop your columns, right click and select the Count option.
Done
Remember, it is important that your both tables are already related to work. Otherwise Power BI will not know how to calculate and displays this combination of data for you.
First create two relationships between Assets and Ticket table. One relationship will be active (one to many) on column AssetKey Column.
Second relationship will be Inactive. Asset[AssetKey] = Ticket[ParentID]
Now use the below Measures -
Number Of Tickets = COUNT(Tickets[TicketKey])
Number of Child = CALCULATE(COUNT(Tickets[AssetKey]),USERELATIONSHIP(Asset[AssetKey],Tickets[ParentId]))
Relationship diagram is in below image :
Output is mentioned below:
The blank row can be eliminated from visual filters :
I am trying to get a list from the database containing two or more lists inside that list.(using .net core, entity framework).Assume I have two table call header and details table.
Header Table
Detail Table
And I want the result like this:
{
"data":[
{
"Country":"Singapore",
"Hospital_List":[
{
"Hospital_Name":"SG Host A"
},
{
"Hospital_Name":"SG Host A"
}
]
},
{
}
]
}
I only know two ways to get the result like this,First Way, select Country list data with blank Hospital list as List,then for loop that list to select related Hospital list from db again.
And Second Way,select Country list data with blank Hospital list as IQueryable List,and then select related Hospital list via jointing with Hospital Table.So my question is
Which way should i used to get higher performance? And Is any other way?
Please remember there has a lot of field and data in my real table.
For loop give give you the lowest perfomance, because you will create SQL query for each iteration. Instead of this, try following solution:
from hospital in hospitals
group hospital by hospital.CID into gh
join country in countries
on gh.FirstOrDefault().CID equals country.CID
select new
{
Country = country.Country,
Hospital_List = from h in gh select h
}
EDITED:
And if your model created right you can use this code:
from hospital in hospitals
join country in countries
on hospital.Country equals country
group hospital by hospital.CID into gh
select new
{
Country = from h in gh select h.Country.Country,
Hospital_List = from h in gh select h
}
I have 2 Models first one is(Plan) and the second is (PlanPrice)
I have this columns in table plan_price:
$table->float('price')->comment('Price for one month or one year depends
on country code');
$table->string('country_code')->default('EG');
What I want is to get a plan with price depends on the user country code.
I think you should do this:
return $this->hasOne(PlanPrice::class, 'plan_id')->where('country_code',
$what_ever_your_code_is);
I want to get count from deep table and the relationship is A->B->C->D and I want total count of D.
For example;
A: 3 Boss
B: 5 Managers
C: 8 Human Resources
D: 25 Employees
Imagine that every boss has managers and every manager has human resources and also every human resource has employees. How can I get total count every boss's employees' with Laravel. (For instance, first boss has 7 employees at the end.) Should I have to write hard sql code like joins or can I handle with eloquent?
By the way, my tables:
A: id, name
B: id, name
A and B has pivot table.
C: id, name
B and C has pivot table
D: id, name
C and D has pivot table
So far, I tried to:
$a = Boss::with("a.b.c.d")->where("id", 10)->first();
dd($a->b->c->d->count());
It just gave me d's count but I want to all of a's.
There is no native relationship for this case.
I created a HasManyThrough relationship with unlimited levels: Repository on GitHub
After the installation, you can use it like this:
class A extends Model {
use \Staudenmeir\EloquentHasManyDeep\HasRelationships;
public function d() {
return $this->hasManyDeep(D::class, ['a_b', B::class, 'b_c', C::class, 'c_d']);
}
}
$count = A::find($id)->d()->count();