Key/Value Store
With the burst of cloud computing on the web a “new” type of database approach has become a more suitable option for some database solutions. Key/Value store also known as NoSQL, has become an increasingly accepted solution for applications with scalability in mind.
Properties of a key/value database model
1. Contain domains which are like tables in the relational model, but unlike a table
you do not define a schema at the domain.
2. Items are identified by keys, and an item can have a dynamic set of attributes attached
to it.
3. No relationships are explicitly defined
Car
Key Attributes 1 Make : Honda Model : Civic Color : Black Year :2002 2 Make: Honda Model : Civic Color : Black Color : White Year : 2000 Transmission : Auto
Example of Key/Value Domain
Key/value databases are item-oriented, which means that all relevant data associated with an item is stored within that item (see diagram). A domain, which is like a relational table, may contain data items that differ greatly in type and size. This model allows a single item to contain all relevant data, which improves scalability by eliminating the need to join data from multiple tables.
Because of key/values ability to scale it has become the database for choice for vendors of web platform data stores. Users of this type of database service will pay only for what they need, and allows the vendor to scale the platform dynamically with minimal limitation on the entire size. Current companies that provide key/value data stores include Amazon’s SimpleDB and Google’s AppEngine.