I have three tables. I want to display all data from cms_planner table together with Topic Name from cms_topic table. To achieve that, I need to go through the cms_subject table.
I want to use belongsToMany but I already have cms_subject table that holds the foreign key for cms_planner and the foreign key for cms_topic. The table name does not represent pivot key.
I also want to use hasManyThrough but it doesn't work. I'm thinking to inverse the hasManyThrough.
How can I achieve that?
1. CmsPlanner
i. planner_id
ii. subject_id
iii. date_start
2. CmsSubject
i. subject_id
ii. topic_id
3. CmsTopic
i. topic_id
ii. topic name
In CmsPlanner model
public function subject(){
return $this->hasManyThrough(
'App\CmsTopic',
'App\CmsSubject',
'topic_id', 'topic_id', 'planner_id');}
In CmsPlanner controller
CmsPlanner::with('subject')->get();
Add this relation on CmsSubject
public function cmsTopic()
{
return $this->belongsTo('App\Models\CmsTopic', 'topic_id', 'topic_id');
}
then add following relation on CmsPlanner
public function cmsSubject()
{
return $this->belongsTo('App\Models\CmsSubject', 'subject_id', 'subject_id');
}
to get data
$cms_planner = CmsPlanner::with('CmsSubject')->where('id', $planner_id)->get();
'user' => $this->business->user
Related
I have a GORM query with a preload that works just fine because I'm binding it to a struct called "companies" which is also the name of the corresponding database table:
var companies []Company
db.Preload("Subsidiaries").Joins("LEFT JOIN company_prod ON company_products.company_id = companies.id").Where("company_products.product_id = ?", ID).Find(&companies)
Now I want to do something similar, but bind the result to a struct that does not have a name that refers to the "companies" table:
var companiesFull []CompanyFull
db.Preload("Subsidiaries").Joins("LEFT JOIN company_prod ON company_products.company_id = companies.id").Where("company_products.product_id = ?", ID).Find(&companies)
I've simplified the second call for better understanding, the real call has more JOINs and returns more data, so it can't be bound to the "companies" struct.
I'm getting an error though:
column company_subsidiaries.company_full_id does not exist
The corresponding SQL query:
SELECT * FROM "company_subsidiaries" WHERE "company_subsidiaries"."company_full_id" IN (2,1)
There is no "company_subsidiaries.company_full_id", the correct query should be:
SELECT * FROM "company_subsidiaries" WHERE "company_subsidiaries"."company_id" IN (2,1)
The condition obviously gets generated from the name of the struct the result is being bound to. Is there any way to specify a custom name for this case?
I'm aware of the Tabler interface technique, however it doesn't work for Preload I believe (tried it, it changes the table name of the main query, but not the preload).
Updated: More info about the DB schema and structs
DB schema
TABLE companies
ID Primary key
OTHER FIELDS
TABLE products
ID Primary key
OTHER FIELDS
TABLE subsidiaries
ID Primary key
OTHER FIELDS
TABLE company_products
ID Primary key
Company_id Foreign key (companies.id)
Product_id Foreign key (products.id)
TABLE company_subsidiaries
ID Primary key
Company_id Foreign key (companies.id)
Subsidiary_id Foreign key (subsidiaries.id)
Structs
type Company struct {
Products []*Product `json:"products" gorm:"many2many:company_products;"`
ID int `json:"ID,omitempty"`
}
type CompanyFull struct {
Products []*Product `json:"products" gorm:"many2many:company_products;"`
Subsidiaries []*Subsidiary `json:"subsidiaries" gorm:"many2many:company_products;"`
ID int `json:"ID,omitempty"`
}
type Product struct {
Name string `json:"name"`
ID int `json:"ID,omitempty"`
}
type Subsidiary struct {
Name string `json:"name"`
ID int `json:"ID,omitempty"`
}
Generated SQL (by GORM)
SELECT * FROM "company_subsidiaries" WHERE "company_subsidiaries"."company_full_id" IN (2,1)
SELECT * FROM "subsidiaries" WHERE "subsidiaries"."id" IN (NULL)
SELECT companies.*, company_products.*, FROM "companies" LEFT JOIN company_products ON company_products.company_id = companies.id WHERE company_products.product_id = 1
Seems like the way to go in this case may be to customize the relationship in your CompanyFull model. Using joinForeignKey the following code works.
type CompanyFull struct {
Products []*Product `json:"products" gorm:"many2many:company_products;joinForeignKey:ID"`
Subsidiaries []*Subsidiary `json:"subsidiaries" gorm:"many2many:company_subsidiaries;joinForeignKey:ID"`
ID int `json:"ID,omitempty"`
}
func (CompanyFull) TableName() string {
return "companies"
}
func main(){
...
result := db.Preload("Subsidiaries").Joins("LEFT JOIN company_products ON company_products.company_id = companies.id").Where("company_products.product_id = ?", ID).Find(&companies)
if result.Error != nil {
log.Println(result.Error)
} else {
log.Printf("%#v", companies)
}
For more info regarding customizing the foreign keys used in relationships, take a look at the docs https://gorm.io/docs/many_to_many.html#Override-Foreign-Key
I have 2 Models, and I want it to show the Name of the Faculty instead of the ID shown below.
enter image description here
I am displaying the User's own Article that has submitted it.
How can I change an ID to a Name Faculty that contains that ID?
Edit your repository by including the foreign key columns like this
public IEnumerable<Article> GetPersonalArticles(string userName)
{
return _dbContext.Articles.Include(a=>a.Faculty).Where(a => a.Author == userName).ToList();
}
I have a problem with Laravel 7 Eloquent. I have 2 tables joined by many to many relation. Table user is connected to PaymentModule by pivot table PaymentModuleUser. I need to use where on pivot table on statement is_active = 1. When i use toSQL() in my model SQL returns good results but when i check my Eloquent Query in Controller, data that i revicive ignore my wherePivot method (return all data from table ignoring is_active = 1 field subscribers = null and get me this user.. I must do it if my pivotWhere = null dont show this user). Could you point me where i get wrong with my code?
My UserTable model:
public function subscriber(){
return $this->belongsToMany(PaymentsModule::class, 'payment_module_user', 'user_id')->withPivot('is_active');
}
MyController:
$users = User::with(['subscriber'=>function($query)
{
$query->wherePivot('is_active','=', 1);
}])->get();
print_r($users);
Try with
$users = User::with('subscriber' => function($query) {
$query->where('payment_module_user.is_active', 1);
})->get();
print_r($users);
The pivot table is already joined by eloquent, so just start using it
Found it here.
In your controller, try using this
$query->wherePivot('is_active', 1);
Instead of,
$query->wherePivot('is_active','=', 1);
Let's say I have a table like this:
CREATE TABLE book (
id INTEGER PRIMARY KEY,
title VARCHAR(32) NOT NULL
);
and I want to support query with offset in order to support API that would return a list of books, ordered by non-unique title field with a given offset and limit.
The question here is what is the most efficient way [1] to define a unique index (or helper column or anything like that) for non-unique title column that could be used as an opaque offset token in queries where I'm using ORDER BY title. I thought about an index created on function that would return a unique numeric position of a row but I'm afraid that this would severely affect timings for INSERTs and UPDATEs for big tables and I think there is an optimal solution for that.
While this is straightforward for ORDER BY {unique_field} queries [2] I don't see an easy way to achieve the same for non-unique fields.
Also let's assume that solution should work in postgresql and mysql.
Notes:
[1] Since straightforward solutions like SELECT id, title FROM book ORDER BY title OFFSET [number] LIMIT [number] work extremely bad for big numeric offset values, I would introduce some sort of opaque token that would represent an offset in a given set in my API for getting book chunks.
So API method that would return a list of books ordered by title with a given offset would look like this (pseudocode):
BookPage getBooks(optional string offsetToken, int limit)
where BookPage is defined as follows:
class BookPage {
nonnull List<Book> books;
nonnull string offsetToken; // expected to be used to return a next page
}
Example use, book table contains 2*N books:
// 1st call
BookPage page1 = getBooks(null, 2); // get first 2 books
BookPage page2 = getBooks(page1.offsetToken, 2); // get next 2 books
BookPage page3 = getBooks(page2.offsetToken, 2); // get next 2 books
//...
BookPage pageN = getBooks(pageN-1.offsetToken, 2); // get last 2 books
and a concatenation of lists page1.books, page2.books, ... pageN.books would produce a list of books ordered by title in ascending order.
[2] For example: If getBooks API would use offset queries where books ordered by id (which is a primary key) offsetToken would be an id of the last book and implementation of getBooks API would look as follows (pseudocode):
BookPage getBook(optional string offsetToken, int limit) {
Long startId = (offsetToken != null ? toLong(offsetToken) : null);
page.books = (SELECT id, title FROM books
WHERE :startId IS null OR id>:startId
ORDER BY id
LIMIT :limit);
page.offsetToken = toString(lastElementOf(page.books).id)
return page;
}
The easiest and simplest solution that I found so far is to use a non-unique column in conjunction with the primary key. It slightly complicates select queries - e.g. for original problem you need to write something like (title = :title AND id > :id) OR (title > :title), where :title and :id constitute offsetToken (last item's title and id).
I have an entity called Books that can have a list of more books called RelatedBooks.
The abbreviated Book entity looks something likes this:
public class Book
{
public virtual long Id { get; private set; }
public virtual IList<Book> RelatedBooks { get; set; }
}
Here is what the mapping looks like for this relationship
HasManyToMany(x => x.RelatedBooks)
.ParentKeyColumn("BookId")
.ChildKeyColumn("RelatedBookId")
.Table("RelatedBooks")
.Cascade.SaveUpdate();
Here is a sample of the data that is then generated in the RelatedBooks table:
BookId RelatedBookId
1 2
1 3
The problem happens when I Try to delete a book. If I delete the book that has an ID of 1, everything works ok and the RelatedBooks table has the two corresponding records removed. However if I try to delete the book with an ID of 3, I get the error "The DELETE statement conflicted with the REFERENCE constraint "FK5B54405174BAB605". The conflict occurred in database "Test", table "dbo.RelatedBooks", column 'RelatedBookId'".
Basically what is happening is the Book cannot be deleted because the record in the RelatedBooks table that has a RelatedBookId of 3 is never deleted.
How do I get that record to be deleted when I delete a book?
EDIT
After changing the Cascade from SaveUpdate() to All(), the same problem still exists if I try to delete the Book with an ID of 3. Also with Cascade set to All(), if delete the Book with and ID of 1, then all 3 books (ID's: 1, 2 and 3) are deleted so that won't work either.
Looking at the SQL that is executed when the Book.Delete() method is called when I delete the Book with an ID of 3, it looks like the SELECT statement is looking at the wrong column (which I assume means that the SQL DELETE statment would make the same mistake, therefore never removing that record). Here is the SQL for the RelatedBook
SELECT relatedboo0_.BookId as BookId3_
, relatedboo0_.RelatedBookId as RelatedB2_3_
, book1_.Id as Id14_0_
FROM RelatedBooks relatedboo0_
left outer join [Book] book1_ on relatedboo0_.RelatedBookId=book1_.Id
WHERE relatedboo0_.BookId=3
The WHERE statment should look something like this for thie particular case:
WHERE relatedboo0_.RelatedBookId = 3
SOLUTION
Here is what I had to do to get it working for all cases
Mapping:
HasManyToMany(x => x.RelatedBooks)
.ParentKeyColumn("BookId")
.ChildKeyColumn("RelatedBookId")
.Table("RelatedBooks");
Code:
var book = currentSession.Get<Book>(bookId);
if (book != null)
{
//Remove all of the Related Books
book.RelatedBooks.Clear();
//Get all other books that have this book as a related book
var booksWithRelated = currentSession.CreateCriteria<Book>()
.CreateAlias("RelatedBooks", "br")
.Add(Restrictions.Eq("br.Id", book.Id))
.List<Book>();
//Remove this book as a Related Book for all other Books
foreach (var tempBook in booksWithRelated)
{
tempBook.RelatedBooks.Remove(book);
tempBook.Save();
}
//Delete the book
book.Delete();
}
Rather than setting the cascade attribute, I think you need to simply empty the RelatedBooks collection before deleting a book.
book.RelatedBooks.Clear();
session.Delete(book);
Cascading deletes is not typically done in a many-to-many relationship because it will delete the object at the other end of the relationship, in this case a Book.
This just got updated:
http://fluentnhibernate.lighthouseapp.com/projects/33236/tickets/115-self-referencing-relationships