CODD'S 3rd RULE

CODD'S 3rd RULE - fields. There is no value for that field....

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CODD’S 3 rd RULE Systematic Treatment of Null Values
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PRESENTED BY: PRADEEP KUMAR PAL DIPAL GAJJAR NISHIT DOSHI
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THE RULE Null values are supported in a fully relational DBMS for representing missing information and inapplicable information in a systematic way, independent of the data type.
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RULE ( CONTD…) A null value can mean that data is not there, is not known, or is irrelevant. The null value represents empty database
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Unformatted text preview: fields. There is no value for that field. A primary key should never have an empty field. This is part of the definition of the primary key. This protects the integrity of the database EXAMPLE OF NULL VALUE Roll No. Name Stream Mobile No. 19 PRADEEP AST 9823514543 20 DIPAL AST 21 NISHIT AST 9890198902 PRIMARY KEY NULL VALUE THANK YOU...
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This note was uploaded on 07/15/2011 for the course ECO 2023 taught by Professor Mr.raza during the Summer '10 term at FAU.

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CODD'S 3rd RULE - fields. There is no value for that field....

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