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Re: Codd's Rule of RDBMS [message #101925] Mon, 26 November 2001 04:27 Go to next message
rajesh
Messages: 173
Registered: November 1998
Senior Member
12 codd's rule statements

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Re: Codd's Rule of RDBMS [message #102093 is a reply to message #101925] Sun, 10 February 2002 19:54 Go to previous messageGo to next message
amitart1@mailcity.com
Messages: 1
Registered: February 2002
Junior Member
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Re: Codd's Rule of RDBMS [message #102695 is a reply to message #101925] Sat, 31 August 2002 00:03 Go to previous messageGo to next message
Iram
Messages: 1
Registered: August 2002
Junior Member
Plz send these rule
Re: Codd's Rule of RDBMS [message #103069 is a reply to message #101925] Sun, 26 January 2003 05:17 Go to previous messageGo to next message
S.RAJESH KUMAR
Messages: 1
Registered: January 2003
Junior Member
THE RULES : 0. (Yes, there is a Rule 0!)
For a system to qualify as a RELATIONAL, DATABASE, MANAGEMENT system, that system must
use its RELATIONAL facilities (exclusively) to MANAGE the DATABASE.

1. The information rule
The information rule simply requires all information in the database to be represented
in one and only one way, Namely by values in column positions within rows of tables.

2. The guaranteed access rule
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 mane of the containing table, the name of the containing column and the
primary key value of the containing row.

3. Systematic treatment of null values
The DBMS is required to 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.

4. Active online catalog based on the relational model
The system is required to support an online, inline, relational catalog that is
accessible to authorized users by means of their regular query language.

5. The comprehensive data sublanguage rule
The system must support a least one relational language that
(a) has a linear syntax,
(b) can be used both interactively and within application programs,
and (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).
6. The view updating rule
All views that are theoretically updatable must be updatable by the system.

7. High-level insert, update, and delete
The system must support set-at-a-time INSERT, UPDATE, and DELETE operators.

8. Physical data independence
Self-explanatory.

9. Logical data independence
Self-explanatory

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.

11. Distribution independence
Existing applications should continue to operate successfully
(a) when a distributed version of the DBMS is first introduced;
(b) when existing distributed data is redistributed around the system.

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 (e.g.) bypassing a relational
security or integrity constraint.

ASK FOR ANY DOUDTS I CAN CLEAR U"R DOUDTS

contact me:rajeshctindia@yahoo.com
queries [message #103443 is a reply to message #103069] Sat, 27 September 2003 06:26 Go to previous message
Mukhtar
Messages: 1
Registered: September 2003
Junior Member
1. How many codd's rule does Oracle9i obeys.

2. What are advantages of Oracle database than any other like SAP,DB2,Informix,SQL Server.

3. How Oracle is more fast & secure than any others.
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