CODD’S RULES

CODD’S RULES

0)      Single Foundation Rule :

                                                    RDBMS must manage every aspect within itself. Without using an external language. Processing should not be done with external storage.

– Define :

                                Each RDBMS has it own file system not use the operating system file. Oracle has its own file system. It initializes in memory at the time of start up & storage is also in oracle file system & can’t access by explorer (windows explorer). It can’t take any type of help with other file system.

1)      Information Rule :

                                           Information can be represented in one and only way that is “TABLES”.

– Define :

                  RDBMS store its information in the form of table even the data about data is also store in table form.

2)      Guaranteed Access :

                                     Access to tables follow the sequence of table name, tupuole, attributes. Every step of data guarantee has been identified access to your work area involves qualifying the user “name” and “passwords”.

–  Define:

                   Oracle has the account of user and its password. Without it user can’t access it. It can create by a DBA against the request of user.

3)      System able Treatment of Null :

                                                        RDBMS should be able to operate with “null value”. Operations with null should be performing by a single command.

– Define:

                 ‘Null’ means nothing. Oracle has the facility to handle the null value. If we assign any field ‘not null’ we must enter the record in this key like the primary key of record. We can insert the ‘0’ value easily on that place where the value is ‘null’

4)      Active On-line Catalog :

                                            The RDBMS should maintain data dictionary tables (catalog).

– Define:

                  All the data in any table but that information is in summary form present in ‘catalog’ access by ‘DBA’. The another name of catalog is ‘active online catalog’. Catalog is the main characteristics of RDBMS. Catalog has the data about data called “META DATA”. Like ‘fat’ on disk have the data about data on disk.                 

5)      Comprehensive Data Sub-Language:

                          (DSL)  RDBMS should have transactional.

                            (DDL) Data definition language.

                          (DML) Data manipulation language

                            (DCL) Data control language)

– Define:

                 Oracle has some sub-languages like.

       DDL (data definition language)

                    Define table

      DML (data manipulation language)

                    Data manipulation

     DCL  (data control language)

                   Create user, create table etc.

    DRL  (data retrial language)

                    Retrieve data with commands

                                                                                              

6)      View Updating Rule :

                                         Each distinct row of a view must correspond to a distinct and uniquely identifiable row of the base table.

– Define:

                DBA gives the right to access any table. DBA design a view in which user access only those records in which BDA gives the rights. if we changing in view already effect in table. If we changing in table take already in view. User rights gives by DBA.

7)      High Level Global Insert,Detete & update :

                                                                            By single command insertions, deletions and replacements should be possible.

– Define:

                  In oracle insertion, Deletion, updating must be held on one command. Means one command for insertion, one for deletion and one for updating.        

8)      Physical Data Independence :

                                                     Recording on the data base should be left to the desecration of the type of system used.

– Define:

                  In oracle if we store any application there is no effect on operating system.

9)      Logical Data Independence :

                                                   Should not be recompiled. Programming efforts should not be wasted as to change logic. Depending on the storage style.

– Define:

                 In oracle the compilation result store in the buffer. If the other user write the some command than compiler give the result of if which they already store in the buffer. But there is a limited data store in the buffer.

10)  Integrity Independence:

                                             Data available should pose no limitations in terms of integration.

– Define:

                    Integrity Independence RDBMS software has no limitation of linking data. Only in the case of hardware capacity. If the hardware capacity is full then we can’t open other table.

11)  Distribution Independence:

                                                   Should look like a centralized system to the user.

– Define:

                 According to this rule user can’t see the complexity of back end environment. They work on simple front-end environment.

12)  Non-Sub Version Rule :

                                            In case of help rendered by some other languages rules governing RDBMS should not be implemented.

– Define:

                 In oracle there is no version clash. We run the oracle 5 commands in oracle 6.

Thanks & Regards,

"Remember Me When You Raise Your Hand For Dua"
Raheel Ahmed Khan
System Engineer
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