Explain Dr.EF code rules of RDBMS

Dr.EF code published twelve rules to define an ideal relational database & provided guidelines to design the software’s. Strictly speaking no RDBMS should satisfy all these twelve rules

1. The information rule:

All the database must be present in a table in the form of columns & rows.

2. Guaranty access rule:

The data should be accessible with any ambiguity confusion .

3. Systematic treatment of null values:

A file should be allowed to remain empty this involves the support of a null value which is distinct from an empty string or a number with a value of zero. This cannot be applied to a primary key.

4. Dynamic online catalogue based on the relational database model

A relational database must provide access to its structure through some of the tools that are used the access the data. This can be accomplished by storing the structure definition with in the special table .

5. Comprehensive database language rule:

The database must support at least one clearly defined language. That includes the functionality such as data definition, data manipulation, data integrity constraints & database transaction controls. Such a language is known as structured query language (SQL). Simply pronounced as sequel for all commercial.

6. View updating rules:

Data can be presented in different logical combinations called views. Each view should support the same range of data manipulations that have direct acts as to a table. In practice providing update & delete access two logical views is difficult are not fully supported any relational data base.

7.High level insert, update & delete rule:

Data can be retrieved in RDBMS as a set of constructed data in multiple rows for multiple tables. This rule states the data must be provided for data anomalies such as insert, update & delete information from the tables.

8.Physical data independence:

The user must be allowed from the physical methods of sharing and retrieving information from the data base. The changes can be made to the underlying architecture, i.e. with in the hardware with the help of software in the disc storage without effecting how the user access it.

9.Logical data independence:

This rule specifies how the data is viewed should not be changed when the structure of the database changes. This is particularly difficult to satisfy because most data bases strongly tie in between the data viewed & actual structure of table.

10.Integrity independence:

The data base language supports integrity constraints on the user input. It is the validation of input at the time of user entry to apply some of the constraints such as no primary key can have a null value (or) remains empty.

11.Distribution independence:

The user should not aware whether the data base is distributed (or) not. The data base must support concurrent access of multiple tables in the distributed system.

12.Non –subversion rule:

There should not be a way to modify the database structure other than RDBMS language.