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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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