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     RDBMS


RDBMS:

  • It stands for relational database management system
  • so the data is stored in the form of the relational model
  • The RDBMS is developed by CODD   when he was working at IBM company in the year 1970
  • so CODD came up with one decision he decided that any information must come to the table





CODD'S RULES

  •  If we satisfy more than 7 rules we can say it is a relational database model

RULE NO 1:- INFORMATION RULE

  •  Every  information must be in the form of rows and columns only
  • any kind of information that must be displayed the basics of  information

RULE NO 2:- GUARANTEED ACCESS RULE

  • It means every piece of information must be accessed and have permission to read and make changes 

  • Every single data element (value) is guaranteed to be accessible logically with a combination of the table name, primary key (row value), and attribute name (column value).

RULE NO 3:-SYSTEMATIC TREATMENT OF NULL VALUES

  • The NULL values in a database must be given a systematic and uniform treatment.
  • If there are no values we can say it contains NULL values
  • Whatever data does not come into the  table we can be called NULL values
  • NULL values means missing values, inconsistent data ..etc

RULE NO 4:-DYNAMIC ONLINE CATALOG BASED ON RELATIONAL MODEL                                    





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