I have tables
Order(orderno,orderdate,suppid)
Supplier(suppid,suppname)
orderdetails(orderdetailid,orderno)
how to get result like this using JPA orderno,orderdate,suppname,orderdetailid?
#ManyToOne
#Fetch(FetchMode.JOIN)
#JoinColumn(name="suppid",nullable=false,insertable=false,updatable=false)
private Supplier supplierDetails;
This will Join one table to another and fetch the record for you.This code should be inside Order table POJO. and getter setter of supplier details as well.
Related
I have retrieved an entity from the database. I would like to update one field (the modified date field) then insert it back to the database as a new entity. How would I achieve that?
I'm trying to add unique columns on a pivot table created via a ManyToMany association.
I found this page of the documentation explaining how to generate a database unique constraint on some columns with this example:
/**
* #Entity
* #Table(name="ecommerce_products",uniqueConstraints={#UniqueConstraint(name="search_idx", columns={"name", "email"})})
*/
class ECommerceProduct
{
}
But this only works if I create the pivot table via a third entity and, in my case, I created the pivot table using a ManyToMany relation (in the same fashion as this code).
Is there a way to add unique columns on pivot table while still using ManyToMany or do I need to rely on a third entity?
While #Table annotation proposes a uniqueConstraints option, #JoinTable does not. Thus, if you want to add a unique constraint on your association table, you will have to actually create another entity explicitly.
That being said, the default join table should not need anything more than the default configuration set up by Doctrine. Currently, when adding a ManyToMany association, the join table is composed of two fields and a composite primary key relying on both fields is created.
If your association table only contains the two basic fields referring to both sides of your association (which is necessarily the case if you use #ManyToMany), the composite primary key should be all you need.
Here is the generated SQL for the basic example where a User has a ManyToMany association with Group (from this section of the documentation):
CREATE TABLE users_groups (
user_id INT NOT NULL,
group_id INT NOT NULL,
PRIMARY KEY(user_id, group_id)
) ENGINE = InnoDB;
ALTER TABLE users_groups ADD FOREIGN KEY (user_id) REFERENCES User(id);
ALTER TABLE users_groups ADD FOREIGN KEY (group_id) REFERENCES Group(id);
As you can see, everything is properly set up with a composite primary key which will ensure that there can't be duplicate entries for the couple (user_id, group_id).
Of course there is another alternative, Alan!
If you need a Zero to Zero relationship, the only alternative is defining the unique constraint per each pk in the agregated table, to make doctrine figuring out about zero to zero relationship.
The problem is that Doctrine's people hadn't considered zero to zero relationships, so the only alternative for this is manytomany relationship with one unique constraint per pk.
If you have doubts about final-state of your doctrine implementation of your E-R model, I strongly recommend mysql-workbench-schema-exporter. With this php tool, you can easily export your mysql workbench E-R schema to a Doctrine's working classes schema, so you would be able to easily explore all your alternatives ;-)
Hope this helps
I have three tables "category", "product" and "product_category".
First two tables are created from two entity Category and Product.
Third table "product_category" is auto generated by framework doctrine console command.
Now I can get (fetch) product relational data (based on category id) from below query, which is fine.
$this->createQueryBuilder('p')
->leftJoin('p.category', 'c')
->select('p')
->where('c.id = :category_id')
->setParameter('category_id', 2)
->getQuery()->getSQL();
But how can I use Many-to-Many relation to Update Data?
I had Tried with several queries but its not working!!!
( I want to update all product status to inactive (2), whose category status is (2 = Inactive).
When doing a query on a table that has children. You can also just fetch the parent item, and doctrine will automatically handle the child objects. If you have a getCategory within the Product entity, it will resolve the category automatically.
Probably what you are looking for is cascading of events. of which is explained within Doctrine 2 ManyToMany cascade
I'm researching whether to try Doctrine2 or not. One thing that scares me is the over SELECTing of columns I don't need (ie. consider lots of varchars being selected unnecessarily).
You might ask: but don't you want your full entity object filled? Yes, unless I'm looking for an array hydration. However, many times I don't need the full aggregation filled. Take the association shown below. If I query the Users table with a JOIN on Address, will all the columns from the address table be SELECTed as well (and therefore populated into an address object inside of users object)? Now imagine we have more JOINs. This could get really bad. What if I only want the fields from User populated in just a users only object? I guess I'm a little confused at what Doctrine is doing behind the scenes with associations and query JOINs.
/** #Entity **/
class User
{
// ...
/**
* #ManyToOne(targetEntity="Address")
* #JoinColumn(name="address_id", referencedColumnName="id")
**/
private $address;
}
/** #Entity **/
class Address
{
// ...
}
So does Doctrine2 populate all the fields of all the objects within the aggregate after a query (unless I specifiy partial)?
It depends on your query, but generally it is not implicit.
Using the query builder, you can fetch the associated record like this:
<?php
$qb = $em->createQueryBuilder();
$query = $qb->select(array("u", "a"))
->from("User", "u")
->innerJoin("u.address", "a")
->getQuery();
In the select() statement you specify what to fetch, in this case you get both.
If you only fetch the User records, then when you get the associated record with $user->getAddress(), Doctrine will make the query on the fly and hydrate the Address record for you.
That said, performance wise it is better to select both entities so Doctrine will make only one query and not 1+N queries
Good morning. I have been looking all over trying to answer this question.
If you have a table that has foreign keys to another table, and you want results from both tables, using basic sql you would do an inner join on the foreign key and you would get all the resulting information that you requested. When you generate your JPA entities on your foreign keys you get a #oneToone annotation, #oneToMany, #ManyToMany, #ManyToOne, etc over your foreign key columns. I have #oneToMany over the foreign keys and a corresponding #ManyToOne over the primary key in the related table column I also have a #joinedON annotation over the correct column... I also have a basic named query that will select everything from the first table. Will I need to do a join to get the information from both tables like I would need to do in basic sql? Or will the fact that I have those annotations pull those records back for me? To be clear if I have table A which is related to Table B based on a foreign key relationship and I want the records from both tables I would join table A to B based on the foreign key or
Select * From A inner Join B on A.column2 = B.column1
Or other some-such non-sense (Pardon my sql if it is not exactly correct, but you get the idea)...
That query would have selected all column froms A and B where those two selected column...
Here is my named query that I am using....
#NamedQuery(name="getQuickLaunch", query = "SELECT q FROM QuickLaunch q")
This is how I am calling that in my stateless session bean...
try
{
System.out.println("testing 1..2..3");
listQL = emf.createNamedQuery("getQuickLaunch").getResultList();
System.out.println("What is the size of this list: number "+listQL.size());
qLaunchArr = listQL.toArray(new QuickLaunch[listQL.size()]);
}
Now that call returns all the columns of table A, but it lack's the column's of table B. My first instinct would be to change the query to join the two tables... But that kind of makes me think what is the point of using JPA then if I am just writing the same queries that I would be writing anyway, just in a different place. Plus, I don't want to overlook something simple. So what say you stack overflow enthusiasts? How does one get back all the data of joined query using JPA?
Suppose you have a Person entity with a OneToMany association to the Contact entity.
When you get a Person from the entityManager, calling any method on its collection of contacts will lazily load the list of contacts of that person:
person.getContacts().size();
// triggers a query select * from contact c where c.personId = ?
If you want to use a single query to load a person and all its contacts, you need a fetch in the SQL query:
select p from Person p
left join fetch p.contacts
where ...
You can also mark the association itself as eager-loaded, using #OneToMany(lazy = false), but then every time a person is loaded (vie em.find() or any query), its contacts will also be loaded.