Do you know which databse Google uses?Its NOSQL ,a schema less database implemented by very big companies like google,facebok,Digg etc. in ordr to provide consistence in data as well as fast indexing as compared to RDMS.Share some more details here .Its indeed an interesting topic as well
Ok i will let you know in brief about it
NOSQL means not Only SQl .means much more than simple sql.It works with more scalability than rdbms.The NoSQL approach presents huge advantages over SQL databases because it allows one to scale an application to new levels. The new data services are based on truly scalable structures and architectures, built for the cloud, built for distribution, and are very attractive to the application developer. There's no need for DBA, no need for complicated SQL queries and it is fast. Hooray, freedom for the people!
Source:-Here (http://xeround.com/blog/2010/12/nosql-the-sequel#comment-7622)
As I know Facebook use MySQL and Google uses it's won db see here for more about google db http://stackoverflow.com/questions/362956/what-database-does-google-use
Thank you my friend for the post really got some idea of the Google database and understood some basic facts after reading the replies quiet, such things are quiet helpful and indeed important for understanding the basic design of Google data structure and analysis ..keep updаting such good content.