What are the requirements of a database to be relational ?

[kALAMATHI]

Hello friends , I an IT student and I am pursuing a graduation course in it , the subject which like the most is the Database management system, because we have a very nice professor for it, yesterday in the session there was a debate about the relational database , an many student had given there comment on this topic to prove themselves , however I could not comprehend to those debates so I am taking your assistance , can anyone please tell me what are the pre-requisite for a database to be relational.

[Villiers]

A relational database is a collection t of tables having data built-in predefined groups. Each relation includes one or more data groups in fields . Each tuple holds a distinct instance of data for the categories described by the fields . You had asked about how a database can be relational , I think EF Codd had mention 12 points that should be there if you want to create a database relational . If you ask me you need to satisfy any six of those 12 points

[Dwarner]

The explanation of a relational database consequences in a relation of metadata or proper descriptions of the relation and its fields along with the domain and its constraint and domains.A relational database has the significant advantage of being simple to expand. After the actual database creation, a new data class can be added without and you need not modify all the existing applications in it .

[Ronchi]

When generating a relational database, you can describe the domain of probable values in a data fields and additional constraints that may be relevant to that data value. For example, a domain of probable students could allow up to ten possible student names but be forced in one table to permitting only any 4 of these student names to be specifiable. Each such relation is recognized by a primary key.

[Jacques25]

A relational database is a set of data items prearranged as a collection of formally-defined tables from which data can be controlled or re accumulated in various ways without having to reorder the database tables. The relational database was brought into picture by E. F. Codd at IBM in 1970. The normal user and software program interface to a relational database is a language called as structured query language and in short it is called as SQL