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(a) Design a query plan for the following distributed query: An application at site B wants to compute a join of STUDENT ?Id=StudId TRANSCRIPT where STUDENT (Id,Major) is at site B and TRANSCRIPT (StudId, CrsCode) is at site C. The result should be returned to B. Assume that semijoin is not used. Also assume that
(b) Estimate the cost of computing σMajor='CS' (STUDENT) ?Id = StudId TRANSCRIPT using the semijoin strategy. Use the sizes of the STUDENT and TRANSCRIPT relations and of their attributes from the part (a) above. In addition, assume that 10% of the students major in CS. Compare this with the solutions in part (a) above that do not use the semijoin.
Explain what is Aggregation ? Aggregation: This is used whenever we intend to show a relationship between an entity and the relationship. There is no provision for this in th
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Explain the Static or conservative Two Phase Locking: Static (or conservative) Two Phase Locking: In this type of scheme, all the data items are locked earlier than any opera
What is foreign key? A relation schema r1 derived from an ER schema may contain among its attributes the primary key of another relation schema r2.this attribute is known as a
Describe briefly models which define the operations on classes. The three models which are used to define operations on classes are as: Object Model = data dictionary + Obje
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how oracle can be used
OPENCART - Want Massive amount of products Imported through CSV We have a massive list of products that would take completely too long to do data entry. We require a slick progr
Ask qu. Write a XML with database with book details (Book ID, Title, Author, subject, published year, language, vendor, and price).estion #Minimum 100 words accepted#
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