Amazon SimpleDB is a highly available and flexible NoSQL data store. Unlike schema-driven relational databases, SimpleDB's flexibility allows you to change your data model on the fly. The infrastructure provisioning, software installation and maintenance, and high availability feature for SimpleDB is managed by AWS; thereby, alleviating the need for typical database administration tasks.
SimpleDB consists of domains where each domain stores a set of records or items. Each of the items has a unique key, and is described by a set of attribute/value pairs. It is not necessary for the items to contain all the attributes. The data in a domain is automatically indexed by each of the attributes, hence enabling access by any one or more attributes. There is no need for a predefined schema and schema changes, in response new attributes are added later on. However, you can run queries on the data stored within a specific domain only. You can also choose...
