what are the stirict criterion that a DBMS package to be termed as RDBMS?

Question

RDBMS-criterions for a DBMS package to be Termed as RDBMS

Answer 1

If it adheres to the 12 rules as stated by E.F. Codd

rules
Rule 0: The system must qualify as relational, as a database, and as a management system.

For a system to qualify as a relational database management system (RDBMS), that system must use its relational facilities (exclusively) to manage the database.

Rule 1: The information rule:
All information in the database is to be represented in one and only one way, namely by values in column positions within rows of tables.

Rule 2 : The guaranteed access rule:
All data must be accessible with no ambiguity. This rule is essentially a restatement of the fundamental requirement for primary keys. It says that every individual scalar value in the database must be logically addressable by specifying the name of the containing table, the name of the containing column and the primary key value of the containing row.

Rule 3: Systematic treatment of null values:
The DBMS must allow each field to remain null (or empty). Specifically, it must support a representation of "missing information and inapplicable information" that is systematic, distinct from all regular values (for example, "distinct from zero or any other number," in the case of numeric values), and independent of data type. It is also implied that such representations must be manipulated by the DBMS in a systematic way.

Rule 4: Active online catalog based on the relational model:
The system must support an online, inline, relational catalog that is accessible to authorized users by means of their regular query language. That is, users must be able to access the database's structure (catalog) using the same query language that they use to access the database's data.

Rule 5: The comprehensive data sublanguage rule:
The system must support at least one relational language that
(a) Has a linear syntax
(b) Can be used both interactively and within application programs,
(c) Supports data definition operations (including view definitions), data manipulation operations (update as well as retrieval), security and integrity constraints, and transaction management operations (begin, commit, and rollback).

Rule 6: The view updating rule:
All views that are theoretically updatable must be updatable by the system.

Rule 7: High-level insert, update, and delete:
The system must support set-at-a-time insert, update, and delete operators. This means that data can be retrieved from a relational database in sets constructed of data from multiple rows and/or multiple tables. This rule states that insert, update, and delete operations should be supported for any retrievable set rather than just for a single row in a single table.

Rule 8: Physical data independence:
Changes to the physical level (how the data is stored, whether in arrays or linked lists etc.) must not require a change to an application based on the structure.

Rule 9: Logical data independence:
Changes to the logical level (tables, columns, rows, and so on) must not require a change to an application based on the structure. Logical data independence is more difficult to achieve than physical data independence.

Rule 10: Integrity independence:
Integrity constraints must be specified separately from application programs and stored in the catalog. It must be possible to change such constraints as and when appropriate without unnecessarily affecting existing applications.

Rule 11: Distribution independence:
The distribution of portions of the database to various locations should be invisible to users of the database. Existing applications should continue to operate successfully :
(a) when a distributed version of the DBMS is first introduced; and
(b) when existing distributed data are redistributed around the system.

Rule 12: The nonsubversion rule:
If the system provides a low-level (record-at-a-time) interface, then that interface cannot be used to subvert the system, for example, bypassing a relational security or integrity constraint.

Retrieved from "http://en.wikipedia.org/wiki/Codd%27s_12_rules"

Answer 2

Who is selling or buying dbms?. Even RDBMS is being replaced by ORDBMS, which is a very powerful solution.

Answer 3

The ability to relate information stored in differnt tables so as to extract data in a grouping or set based upon some logic rule.

For example :
2 tables CarSalemen & CarSold

You have a list of carsales men with their personal infor such as name ecit. Each unique saleman has a single record

Cars sold is a list of type of car its price and who sold it.
Each uique vehicle sold has its own record. A saleman could hove sold 10 different cars then his name would appear in 10 different records for each car he sold

You link the two tables by relating the salesman name in both tables. This allows information appearing in one record in a single record like a salesman phone number to be displayed along side a list of each car sold in a particular month.

We have related one salesman record to many different car records.

The power of this is that if the phone number is changed for example you only have to change it in a single location (saleman data table) and not in the many different records of the cardata table.