One to Many 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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  • var id = ObjectId()
  • db.child_collection.insert({_id:id, field:value})
  • db.parent_collection.insert({dbref_field:{"$ref":"parent_collection","$id":id,"$db":name_of_child_database"})

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

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  • Use the appropriate class supplied by your driver