Top "Orm" questions

What is the difference between @ManyToOne(optional=false) vs. @Column(nullable=false)

In JPA, I am confused when to use the attribute optional=false and the annotation @Column(nullable=false). What is …

java hibernate orm jpa

How should equals and hashcode be implemented when using JPA and Hibernate

How should model class's equals and hashcode be implemented in Hibernate? What are the common pitfalls? Is the default implementation …

java hibernate orm equals hashcode

What is the difference between fetch="EAGER" and fetch="LAZY" in doctrine

What is the difference between fetch="EAGER" and fetch="LAZY" in annotation @ManyToOne in Doctrine ? /** * @ManyToOne(targetEntity="Cart", cascade={"all"}, …

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PHP ORMs: Doctrine vs. Propel

I'm starting a new project with symfony which is readily integrated with Doctrine and Propel, but I of course need …

php orm symfony1 doctrine propel

Django queries - id vs pk

When writing django queries one can use both id/pk as query parameters. Object.objects.get(id=1) Object.objects.get(…

django orm primary-key

How do I map a composite primary key in Entity Framework 4 code first?

I'm getting to grips with EF4 code first, and liking it so far. But I'm having trouble mapping an entity …

entity-framework orm composite-key

Filter by property

Is it possible to filter a Django queryset by model property? i have a method in my model: @property def …

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Multiple unique constraints in JPA

Is there a way to specify using JPA that there should be multiple unique constraints on different sets of columns? @…

java hibernate jpa orm datanucleus

Is it possible to generate django models from the database?

I've been messing around with Django and the Django ORM at home, and I've got to say, I feel it …

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Why should you use an ORM?

If you are motivate to the "pros" of an ORM and why would you use an ORM to management/client, …

database orm