Update Inventory BEGIN TRANSACTION Update Products Set Inventory = Inventory - @QuantityOrdered Where ProductID = 12242323 If (Select Inventory from Products Where ProductId = 12242323) < 0 ROLLBACK TRANSACTION COMMIT TRANSACTION t
And SQL.. SQL is a powerful expressive DSL (Domain Specific Language) that many, many people understand.
A vailability C onsistency P artition tolerant MongoDB MySQL SQL Server Oracle RDBMs HBase (Hadoop) Google BigTable Dynamo Couch Cassandra Voldemort Redis SimpleDB CAP
FriendsWhoCook.com A social network of friends who enjoy cooking great food. -Add my Recipes -Add my friends -Show my friends -Like / Comment on my Friends Recipes -Search recipes of my friends, their friends, and so on by.
Friends in RDBMS For a more sophisticated view of modeling graphs in an RDBMs: http://www.slideshare.net/quipo/rdbms-in-the-social-networks-age
Get my Friends Declare @ProfileID int SELECT FirstDegreeProfile.ID, FirstDegreeProfile.FirstName, FirstDegreeProfile.LastName FROMProfile AS FirstDegreeProfile JOIN Friendship ON FirstDegreeProfile.ID = Friendship.FriendID WHERE Friendship.ProfileID = @ProfileID
Friends and their friends Declare @ProfileID int Set @ProfileID = 1 Select FirstDegreeFriendship.FriendId as MyFriendId, SecondDegreeProfile.ID as SecondDegreeId, SecondDegreeProfile.FirstName as SecondDegreeFirstName, SecondDegreeProfile.LastName as SecondDegreeLastName from Profile as SecondDegreeProfile Join Friendship as SecondDegreeFriendship ON SecondDegreeProfile.ID = SecondDegreeFriendship.FriendID join Friendship as FirstDegreeFriendship ON SecondDegreeFriendship.ProfileID = FirstDegreeFriendship.FriendID Where FirstDegreeFriendship.ProfileId = @ProfileId /* Note: A much better solution would use a recursive CTE to compute transitive closure */
Graph Databases Optimized for graphs data Check out Neo4J
Problem 3: Schemaless / Big Data Facebook's Network: Credit Traud & Frost, UNC-Chapel Hill
How do we ask these questions? After we changed the like button icon for half of our users, did we get more or less likes from that sample? Of users who click on our ads, what pages did they spend the most time on? Which hidden patterns might make us competitive that we arent even aware of? Want to get far ahead of the pack? Read The Lean Startup by Eric Ries
Wide Column A Bigtable is a sparse, distributed, persistent multidimensional sorted map Source: http://jimbojw.com/wiki/index.php?title=Understanding_Hbase_and_BigTable
MapReduce Map(k,v) [(k 1, v 1 ), (k 2, v 2 ), (k 1, v 3 ), (k 3, v 4 )] Map(k, v) (list of intermediate key / value pairs) Internal Step: Takes list of intermediate key value pairs and converts to a key / list of values. Reduce(k, [v 1, v 2, v 3 …]) (k, n 1 ), (k, n 2 )
One Down Side… We have to have smart people write MapReduce programs and the problems need to be expressible as Map Reduce.. General solutions are BIG money.
Things to Read Bigtable: A Distributed Storage System for Structured Data Dynamo: Amazons Highly Available Key-value Store MapReduce: Simplified Data Processing on Large Clusters The Google File System Towards Robust Distributed Systems http://jimbojw.com/wiki/index.php?title=Understanding_Hbase_and_Bi gTable
Creative Commons Acknowledgments and Thanks! Bobwitlox rosipaw