silpi jain

• Sep 26th, 2005

 

twelve rules has introduced by Fcodd,but oracle support 11 rules.

Dinesh Kumar Dubey

• Dec 13th, 2005

 

Which one is not supported?Pls clarify.

Murali

• Dec 22nd, 2005

 

Oracle 8i satisfies 8.5 codde rules

dhpuneet

 Profile Answers by dhpuneet 

• Jan 24th, 2006

 

Hi shilpi

thanks for the info. But please also tell us which rules oracle satisfies & which one it does not. Or if you could provide a site or link that elaborate on this matter it will be great benefit to us.

Quick response will be highly appreciated

Regards,

punu

sreelakshmiI

• Feb 16th, 2006

 

12 rules were proposed by e.f codd

km1102us

 Profile Answers by km1102us Questions by km1102us

• Mar 6th, 2006

 

The 12 codd rule which oracle does not satisfy is

Codd rule says view should be updatable , but views in oracle

are updatable but with constraints i.e two tables are joined to form a view

Pawan Ahuja

• Mar 7th, 2006

 

11 rules is supported out of 12.

the only oracle datbase that support maximum rules.

Regards

Pawan Ahuja

siva

• Mar 23rd, 2006

 

hai

oracle supports 11 codd rules out of 12

view updatation is not support always

view updation is suuported as some extent

RGs

Shiva

Rana

• Apr 5th, 2006

 

Dr. E.F.Codd proposed relational model for database system in 1970

Relational model consist of fallowing:

• Collection of objects or relations
• Set of operators to act on relation
• Data integrity for accuracy and consistancy

12 Rules

Rule 1: The Information Rule
All data should be presented to the user in table form. Last week's newsletter already discussed the basics of this rule.

Rule 2: Guaranteed Access Rule
All data should be accessible without ambiguity. This can be accomplished through a combination of the table name, primary key, and column name.

Rule 3: Systematic Treatment of Null Values
A field 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. Of course, this can't apply to primary keys. In addition, most database implementations support the concept of a nun- null field constraint that prevents null values in a specific table column.

Rule 4: Dynamic On-Line Catalog Based on the Relational Model A relational database must provide access to its structure through the same tools that are used to access the data. This is usually accomplished by storing the structure definition within special system tables.

Rule 5: Comprehensive Data Sublanguage Rule
The database must support at least one clearly defined language that includes functionality for data definition, data manipulation, data integrity, and database transaction control. All commercial relational databases use forms of the standard SQL (Structured Query Language) as their supported comprehensive language.

Rule 6: View Updating Rule
Data can be presented to the user in different logical combinations, called views. Each view should support the same full range of data manipulation that direct-access to a table has available. In practice, providing update and delete access to logical views is difficult and is not fully supported by any current database.

Rule 7: High-level Insert, Update, and Delete
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
The user is isolated from the physical method of storing and retrieving information from the database. Changes can be made to the underlying architecture ( hardware, disk storage methods ) without affecting how the user accesses it.

Rule 9: Logical Data Independence
How a user views data should not change when the logical structure (tables structure) of the database changes. This rule is particularly difficult to satisfy. Most databases rely on strong ties between the user view of the data and the actual structure of the underlying tables.

Rule 10: Integrity Independence
The database language (like SQL) should support constraints on user input that maintain database integrity. This rule is not fully implemented by most major vendors. At a minimum, all databases do preserve two constraints through SQL.

• No component of a primary key can have a null value. (see rule 3)
• If a foreign key is defined in one table, any value in it must exist as a primary key in another table.

Rule 11: Distribution Independence
A user should be totally unaware of whether or not the database is distributed (whether parts of the database exist in multiple locations). A variety of reasons make this rule difficult to implement; I will spend time addressing these reasons when we discuss distributed databases.

Rule 12: Nonsubversion Rule
There should be no way to modify the database structure other than through the multiple row database language (like SQL). Most databases today support administrative tools that allow some direct manipulation of the datastructure.

Ram,esh

• Jul 14th, 2006

 

Hi, I want to know which rule is not supported by Oracle. What is the reason? Explain in detail.

rajakumar_na

 Profile Answers by rajakumar_na 

• Nov 14th, 2007

 

Oracle supportes 11.5 of E.F. CODD Rule. The .5 missing was according to E.F. CODD Rule DML operation through a complex view is possible. But in oracle DML operation through a complex view is not always.

rajakumar_na

 Profile Answers by rajakumar_na 

• Nov 14th, 2007

 

Oracle supportes 11.5 of E.F. CODD Rule. The .5 missing was according to E.F. CODD Rule DML operation through a complex view is possible. But in oracle DML operation through a complex view is not always.

chandusek

 Profile Answers by chandusek 

• Dec 5th, 2007

 

They are 12 codd rules which were proposed by E.F.Codd in 1985(published). 11 rules are supported by oracle. The only one rule which is not supported by the oracle is View Updating Rule why because according to codd every view should support full range of data manipulation but here in oracle the formation of view cant be done by one table. such that it requires two tables so there is no possibility of view updating.

aaravindkumar

 Profile Answers by aaravindkumar 

• Dec 12th, 2007

 

The only rule that is not satisfied by oracle db is the systamatic treatment of NULL values. NULL in oracle is treated as absence of a value or unknown status (in case of comparision of values) and it doesn't have any systamatic representation. In oracle db, no two NULL values are equal (as this will always return a NULL which is treated as unknown by oracle). If there is a systamatic representation then NULL should be comparable.

In case of updatable view, I believe oracle db satisfies the rule as per my understanding of the rule.

Sampath Kumar

• May 24th, 2016

 

Does Oracle 12c supports these 12 Codd Rules