One to One Relationships: DBRef Approach

• What is a "DBRef"

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  • A convention for representing a document in another collection

• What are the restrictions in using the "DBRef" approach?

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  • Not all programming language drivers support this
  • DBRefs supported in: C#, Java, JavaScript, PHP, Python, Ruby
  • DBRefs NOT supported in: C, C++ and perl

• How do you store data using the "DBRef" approach?

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  • db.customers.insert({dbref_field:{"$ref":"collection","$id":ObjectId(of linked document),"$db":"database"});

• How do you query data from a "DBRef"?

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  • Use the appropriate class and method supplied by your driver
  • PHP: MongoCollection::getDBRef