Data Store API documentation

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Contents

[edit] BETA

[edit] Notices 

[1, 2]
["a", "b"]
{ "1": "a", "2": "b" }    // please make sure to use double quotes for both names and values
  • 10/3/07: We found a bug with our complex data structure handling, and currently they may not work as expected. We will post an update when this is fixed.

[edit] Overview

Data Store API is mainly designed to help our platform application developers to quickly come up with a scalable storage solution that can keep up with rapid growth of their user base. Currently there is no plan or intention to charge people on normal usage. We will impose upper limit to ensure fair use of the service between different applications, and we will post the limit when we have it.

There are 3 groups of API functions:

  • Specialized Tables: Since our goal is to simplify platform application development, we provide specialized and, more importantly, optimized table types that are commonly needed by different applications. Currently, there is only User Preference that's implemented. Developers are more than welcome to express their interest in what types of tables they want to have from us.
  • Distributed Tables: We use "object type" throughout the entire API, but conceptually an object type isn't that much different from a distributed database table. "Distributed" is the key, since we really want to make sure data access can be scaled to millions of rows without degradation of performance. Having a large number of rows isn't uncommon to platform applications, since they normally grow exponentially when they become popular among Facebook users. Storing data in a distributed table upfront will ensure the ultimate success of such applications.
  • Associations: The traditional database approach tends to use indices to help query speed. However, indexing a distributed table normally offers no performance gain, due to uncertainty where target objects are and the scalability requirement of not having centralized directory services. Associations are our way of providing fast lookups of objects without ANY centralized indices or parallel queries. It may take our developers some effort to think in the "association" way, but once this thought process is gone through, the final solution is normally scalable with great performance guarantee. Follow this link to read more about what an association is: data.defineAssociation.

Currently, only application developers can view and update object type and association definitions. Only end users of an application can view or update objects that are defined and created by the same application. There is no sharing between different applications, although Facebook objects are accessible through similar FQL interfaces.

[edit] User Preference API

* data.setUserPreference update one preference
* data.setUserPreferences update multiple preferences in batch
* data.getUserPreference get one preference of a user
* data.getUserPreferences get all preferences of a user

[edit] Object Data Definition API

* data.createObjectType create a new object type
* data.dropObjectType delete an object type and all objects of this type
* data.renameObjectType rename an object type
* data.defineObjectProperty add a new property
* data.undefineObjectProperty remove a previously defined property
* data.renameObjectProperty rename a previously defined property
* data.getObjectTypes get a list of all defined object types
* data.getObjectType get detailed definition of an object type

[edit] Object Data Access API

* data.createObject create a new object
* data.updateObject update an object's properties
* data.deleteObject delete an object by its id
* data.deleteObjects delete multiple objects by ids
* data.getObject get an object's properties by its id
* data.getObjects get properties of a list of objects by ids
* data.getObjectProperty get an object's one property
* data.setObjectProperty set an object's one property
* data.getHashValue get a property value by a hash key
* data.setHashValue set a property value by a hash key
* data.incHashValue increment/decrement a property value by a hash key
* data.removeHashKey delete an object by its hash key
* data.removeHashKeys delete multiple objects by their hash keys

[edit] Association Data Definition API

* data.defineAssociation create a new object association
* data.undefineAssociation remove a previously defined association and all its data
* data.renameAssociation rename a previously defined association
* data.getAssociationDefinition get definition of a previously defined association
* data.getAssociationDefinitions get definitions of all previously defined associations

[edit] Association Data Access API

* data.setAssociation create an association between two objects
* data.setAssociations create a list of associations between pairs of objects
* data.removeAssociation remove an association between two objects
* data.removeAssociations remove associations between pairs of objects
* data.removeAssociatedObjects remove all associations of an object
* data.getAssociatedObjects get ids of an object's associated objects
* data.getAssociatedObjectCount get count of an object's associated objects
* data.getAssociatedObjectCounts get counts of associated objects of a list of objects.
* data.getAssociations get all associations between two objects
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