the purpose and features of a relational database?

Question

hello guys i just wondered if there is anyone that can give me an answer for this question in a few lines.thanks what is the purpose and features of a relational database?

Sam Hobbs · Answer

I have the impression that the term hierarchical is not clearly defined in this context. Microsoft uses the term in a manner that is consistent with relational data. I thought that hierarchy applies to related data but I was not aware of the use of the term in that context before a couple of days ago. Whatever the terminology XML allows data to deviate from the rows and columns design that is basic to the relational design.

Vulpes · Answer

Yes the relational model is not ideally suited to hierarchical data which of course XML is. Its dominance may also be threatened by document-oriented databases such as Mongo and CouchDB. In fact there was an article about Mongo on this site earlier this month ( http://www.c-sharpcorner.com/UploadFile/b19d5a/6716/ ).

Sam Hobbs · Answer

There are hundreds of books with answers to this question. There are many more sites in the internet with answers. A few more points I want to add is that at the time that relational databases was invented over fourty years ago by Edgar Codd of IBM there were many types of databases and the relational model was designed to be simple and powerful. Also contrary to what many people say XML is like a database format and as a database XML violates the relational model immensely. I will leave it for others to decide whether that is a good thing but I think one reason XML is used so extensively is because the relational model does not work for everything.

Vulpes · Answer

A relational database is used for information management. It is essentially a set of related data organized into tables. Each table contains a number of records (or rows) and each row contains a number of data fields (or columns). Tables are linked by common fields and rows can be uniquely identified by a field (or combination of fields) known as the primary key. The database can be manipulated or queried using a powerful language called SQL.