type Group struct {
gorm.Model
CreatedBy uint64
GroupOrders []GroupOrder gorm:"many2many:group_orders;association_jointable_foreignkey:group_id;jointable_foreignkey:group_id;"
}
type GroupOrder struct {
gorm.Model
GroupID uint64
OrderID uint64
UserID uint64
Group Group
}
I am trying to insert a record like this
newGroup: = &Group{
CreatedBy: newGroupDetails.UserID,
GroupOrders: []GroupOrder{
{
OrderID: newGroupDetails.OrderID,
UserID: newGroupDetails.UserID,
},
},
}
I am creating a record by using this.
db.Create(newGroup)
It creates a record correctly in Group model but while inserting in GroupOrder model, it is inserting NULL value in group_id column.
After that, it fires a query
INSERT INTO group_orders (group_id) SELECT ? FROM DUAL WHERE NOT EXISTS (SELECT * FROM group_orders WHERE group_id = ?)[30 30] 1 pkg=mysql
And then insert another record in GroupOrder Model with all empty fields but adding the group id field as the previously inserted group_order_id value.
The resultant data in mysql
GroupOrder
| id | group_id | order_id | user_id |
+----+---------------+----------+---------+
| 30 | 0 | 8764822 | 678972 |
| 31 | 30 | NULL | NULL |
Group
| id | created_by |
+----+------------+
| 18 | 678972 |
At least, it should be inserting 18 in place of 30 in the last row group_id column in GroupOrder table.
Why is this happening? Can someone explain if there's a bug.
PS: For brevity, removed a few other columns from both Models.
Found the bug myself. Group has an has-many association with GroupOrder and not many to many. Removed that and it worked clean.
Hope it helps someone :)
Related
I am using laravel eloquent to get the query results. I have two tables below:
users table:
| id | department_id
| 1 | 1
| 2 | 3
| 3 | 2
department table:
| id | name
| 1 | A
| 2 | B
| 3 | C
| 4 | D
| 5 | E
How to get one unassigned ID, not existing department ID, into the users table? Example, 4 & 5 are not yet existing in users table, so how can I get 4 or 5 using an eloquent?
I am thinking of this but this is not correct.
Department::select('department.id as id')
->leftJoin('users', 'users.department_id' ,'department.id')
->pluck('id');
Does anybody know?
Try this
//here you first got all the department which is assigned to user
$assigned_dept = Users::pluck('department_id')->toArray();
$department = array_values($assigned_dept); //output:['1','3','2']
//here you can select department which is not assigned to user with limit
$user = Department::whereNotIn('id',$department)
->limit(1)->get();
hope it works for you..
You can do it like this:
Department::whereNotIn('id', User::pluck('department_id'))->get();
I believe below code will work for you :
Department::select('department.id as id')
->whereNotIn('id', User::whereNotNull('department_id')->pluck('department_id'))
->pluck('id');
From the answers others, there is a problem with the array if department_id is NULL. So, I added whereNotNull and also last() and then the problem is solved. Let me post the answer here:
Department::select('department.id as id')
->whereNotIn('id', User::whereNotNull('department_id')->pluck('department_id'))
->pluck('id')
->last(); // since I only need one row
I have a polymorphic "Relationships" many to many relation that looks like that:
users
id | first_name | last_name
groups
id | group_name
regions
id | region_name
relationships
id | user_id | relationship_id | relationship_type | relationship_level
4 | 13 | 25 | App\Group | Group Manager
5 | 20 | 18 | App\Region | Participant
And the relationship looks like that:
public function regions()
{
return $this->morphedByMany('App\Region', 'relationship')->withPivot('relationship_level')->withTimestamps();
}
public function groups()
{
return $this->morphedByMany('App\Group', 'relationship')->withPivot('relationship_level')->withTimestamps();
}
And vice versa.
When I have an array of IDs, I want to select the relationships that exactly match between the users, this means that all columns (except user_id) match.
And they should only be rows that match among all users. If only 10 out of 12 selected users have the same relationship it should not be included.
If I select 10 users I need to select a pivot record that all those 10 users have (if any).
It doesn't matter if done in eloquent or via the collection after fetching from Database.
Background - I'm creating a system where administrators can create arbitrary fields, which are then combined into a form. Users then complete this form, and the values input against each field are stored in a table. However, rather than overwrite the previous value, I plan on keeping each past value as individual rows in the table. I then want to be able to display the contents submitted in each form, but only the most recently submitted value.
Problem
I have a model, Service, that features a belongsToMany relationship with another model, Field. This relationship is defined as:
public function fields()
{
return $this->belongsToMany('App\Field')->withPivot('id', 'value', 'date')->withTimestamps();
}
The intermediary table has 3 values I wish to retrieve, id, value and date.
A Service may have 1 or more Fields, and for each field it may also have more than 1 pivot row. That is, a single Service/Field pairing may have multiple entries in the pivot table with different pivot values. For example:
Table field_service
id | service_id | field_id | value | created_at
------------------------------------------------------
1 | 1 | 1 | lorem | 2018-02-01
2 | 1 | 1 | ipsum | 2018-01-01
3 | 1 | 1 | dolor | 2017-12-01
4 | 1 | 2 | est | 2018-03-10
5 | 1 | 2 | sicum | 2018-03-09
6 | 1 | 2 | hoci | 2018-03-08
What I want is to get either:
A specific row from the pivot table for each Field associated with the Service, or
A specific value from the pivot table for each Field associated with the Service.
For example - in the table above, I would like the Service with ID 1 to have 2 Fields in the relationship, with each Field containing an attribute for the corresponding pivot value. The Fields attached would be specified by the corresponding pivot table entry having the most recent date. Something akin to:
$service->fields()[0]->value = "lorem"
$service->fields()[1]->value = "est"
I feel there's an obvious, 'Laravel'ly solution out there, but it eludes me...
Update
Somewhat unbelievably this is another case of me not understanding windowing functions. I asked a question 7 years ago that is basically this exactly problem, but with raw MySQL. The following raw MySQL basically gives me what I want, I just don't know how to Laravelise it:
SELECT services.name, fields.name, field_service.value, field_service.created_at, field_service.field_id
FROM field_service
INNER JOIN
(SELECT field_id, max(created_at) as ts
FROM field_service
WHERE service_id = X
GROUP BY field_id) maxt
ON (field_service.field_id = maxt.field_id and field_service.created_at = maxt.ts)
JOIN fields ON fields.id = field_service.field_id
JOIN services ON services.id = field_service.service_id
Try this:
public function fields()
{
$join = DB::table('field_service')
->select('field_id')->selectRaw('max(`created_at`) as `ts`')
->where('service_id', DB::raw($this->id))->groupBy('field_id');
$sql = '(' . $join->toSql() . ') `maxt`';
return $this->belongsToMany(Field::class)->withPivot('id', 'value', 'created_at')
->join(DB::raw($sql), function($join) {
$join->on('field_service.field_id', '=', 'maxt.field_id')
->on('field_service.created_at', '=', 'maxt.ts');
});
}
Then use it like this:
$service->fields[0]->pivot->value // "lorem"
$service->fields[1]->pivot->value // "est"
My pivot table has additional field...
id | user_id | language_id | level
---------------------------------------
and my code:
User::find($this->userId)->languages()->attach(['language_id' => $lang_id, 'level' => $level]);
but the result is:
id | user_id | language_id | level
---------------------------------------
1 1 1 null
1 1 2 null
actually, second line's language_id must be first line's level...
how can i do it properly like this?
id | user_id | language_id | level
---------------------------------------
1 1 1 2
attach() works a bit differently. The first parameter is the id or an instance of the other model and the second parameter are other pivot fields:
User::find($this->userId)->languages()->attach($lang_id, ['level' => $level]);
As #ceejayoz mentioned you also don't have withPivot() defined in your relationship. That means level won't be available in the result. Change that by adding withPivot() to both sides of the relation:
public function languages() {
return $this->belongsToMany('Language')->withPivot('level');
}
Per the docs, you need to define the pivot table's data columns with the relationship.
public function languages() {
return $this->belongsToMany('User')->withPivot('level');
}
I am using the following LINQ query for my profile page:
var userData = from u in db.Users
.Include("UserSkills.Skill")
.Include("UserIdeas.IdeaThings")
.Include("UserInterests.Interest")
.Include("UserMessengers.Messenger")
.Include("UserFriends.User.UserSkills.Skill")
.Include("UserFriends1.User1.UserSkills.Skill")
.Include("UserFriends.User.UserIdeas")
.Include("UserFriends1.User1.UserIdeas")
where u.UserId == userId
select u;
It has a long object graph and uses many Includes. It is running perfect right now, but when the site has many users, will it impact performance much?
Should I do it in some other way?
A query with includes returns a single result set and the number of includes affect how big data set is transfered from the database server to the web server. Example:
Suppose we have an entity Customer (Id, Name, Address) and an entity Order (Id, CustomerId, Date). Now we want to query a customer with her orders:
var customer = context.Customers
.Include("Orders")
.SingleOrDefault(c => c.Id == 1);
The resulting data set will have the following structure:
Id | Name | Address | OrderId | CustomerId | Date
---------------------------------------------------
1 | A | XYZ | 1 | 1 | 1.1.
1 | A | XYZ | 2 | 1 | 2.1.
It means that Cutomers data are repeated for each Order. Now lets extend the example with another entities - 'OrderLine (Id, OrderId, ProductId, Quantity)andProduct (Id, Name)`. Now we want to query a customer with her orders, order lines and products:
var customer = context.Customers
.Include("Orders.OrderLines.Product")
.SingleOrDefault(c => c.Id == 1);
The resulting data set will have the following structure:
Id | Name | Address | OrderId | CustomerId | Date | OrderLineId | LOrderId | LProductId | Quantity | ProductId | ProductName
------------------------------------------------------------------------------------------------------------------------------
1 | A | XYZ | 1 | 1 | 1.1. | 1 | 1 | 1 | 5 | 1 | AA
1 | A | XYZ | 1 | 1 | 1.1. | 2 | 1 | 2 | 2 | 2 | BB
1 | A | XYZ | 2 | 1 | 2.1. | 3 | 2 | 1 | 4 | 1 | AA
1 | A | XYZ | 2 | 1 | 2.1. | 4 | 2 | 3 | 6 | 3 | CC
As you can see data become quite a lot duplicated. Generaly each include to a reference navigation propery (Product in the example) will add new columns and each include to a collection navigation property (Orders and OrderLines in the example) will add new columns and duplicate already created rows for each row in the included collection.
It means that your example can easily have hundreds of columns and thousands of rows which is a lot of data to transfer. The correct approach is creating performance tests and if the result will not satisfy your expectations, you can modify your query and load navigation properties separately by their own queries or by LoadProperty method.
Example of separate queries:
var customer = context.Customers
.Include("Orders")
.SingleOrDefault(c => c.Id == 1);
var orderLines = context.OrderLines
.Include("Product")
.Where(l => l.Order.Customer.Id == 1)
.ToList();
Example of LoadProperty:
var customer = context.Customers
.SingleOrDefault(c => c.Id == 1);
context.LoadProperty(customer, c => c.Orders);
Also you should always load only data you really need.
Edit: I just created proposal on Data UserVoice to support additional eager loading strategy where eager loaded data would be passed in additional result set (created by separate query within the same database roundtrip). If you find this improvement interesting don't forget to vote for the proposal.
(You can improve performance of many includes by creating 2 or more small data request from data base like below.
According to my experience,Only can give maximum 2 includes per query like below.More than that will give really bad performance.
var userData = from u in db.Users
.Include("UserSkills.Skill")
.Include("UserIdeas.IdeaThings")
.FirstOrDefault();
userData = from u in db.Users
.Include("UserFriends.User.UserSkills.Skill")
.Include("UserFriends1.User1.UserSkills.Skill")
.FirstOrDefault();
Above will bring small data set from database by using more travels to the database.
Yes it will. Avoid using Include if it expands multiple detail rows on a master table row.
I believe EF converts the query into one large join instead of several queries. Therefore, you'll end up duplicating your master table data over every row of the details table.
For example: Master -> Details. Say, master has 100 rows, Details has 5000 rows (50 for each master).
If you lazy-load the details, you return 100 rows (size: master) + 5000 rows (size: details).
If you use .Include("Details"), you return 5000 rows (size: master + details). Essentially, the master portion is duplicated over 50 times.
It multiplies upwards if you include multiple tables.
Check the SQL generated by EF.
I would recommend you to perform load tests and measure the performance of the site under stress. If you are performing complex queries on each request you may consider caching some results.
The result of include may change: it depend by the entity that call the include method.
Like the example proposed from Ladislav Mrnka, suppose that we have an entity
Customer (Id, Name, Address)
that map to this table:
Id | Name | Address
-----------------------
C1 | Paul | XYZ
and an entity Order (Id, CustomerId, Total)
that map to this table:
Id | CustomerId | Total
-----------------------
O1 | C1 | 10.00
O2 | C1 | 13.00
The relation is one Customer to many Orders
Esample 1: Customer => Orders
var customer = context.Customers
.Include("Orders")
.SingleOrDefault(c => c.Id == "C1");
Linq will be translated in a very complex sql query.
In this case the query will produce two record and the informations about the customer will be replicated.
Customer.Id | Customer.Name | Order.Id | Order.Total
-----------------------------------------------------------
C1 | Paul | O1 | 10.00
C1 | Paul | O2 | 13.00
Esample 2: Order => Customer
var order = context.Orders
.Include("Customers")
.SingleOrDefault(c => c.Id == "O1");
Linq will be translated in a simple sql Join.
In this case the query will produce only one record with no duplication of informations:
Order.Id | Order.Total | Customer.Id | Customer.Name
-----------------------------------------------------------
O1 | 10.00 | C1 | Paul