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Describe entity referential integrity and integrity. Give an example of each.
Entity Integrity Rule - If there is a attribute A of relation R is a prime attribute of R then A cannot accept null values.
Referential Integrity Rule - In referential integrity, it is ensured in which a value in which appears in one association for a given set of attributes also appears for a certain set of attributes in another relation.
For example:
Roll No is the primary key within the relation STUDENT and Roll No + Course is the primary key of the relation GRADE. (Entity Integrity) Roll No in the relation GRADE (child table) is a foreign key, which is referenced from the relation STUDENT (parent table). (Referential Integrity).
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Show a centralised schema to support the operation of the system you have chosen, including in particular: the product catalogue; the outlets and respective stocks; customer record
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Spanned and unspanned organisation? Spanned and unspanned organization: If records are not permited to cross block boundaries then the organisation is called unspanned record
WHY SHOULD NULL IN A RELATION BE AVOID AS possible?
Illustrate the collaboration and relationship diagram A collaboration is the society of interfaces, classes and other elements which work together to provide some cooperative b
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