Using High-Level Conceptual Data Models for Database Design






Frequently Asked Questions

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Ans: The similarities and differences between conceptual modeling and knowledge representation, and introduces some of the alternative terminology and a few additional concepts.The goal of KR techniques is to develop concepts for accurately modeling some domain of knowledge by creating an ontology that describes the concepts of the domain and how these concepts are interrelated. view more..
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Ans: The basic notation for specialization/generalization is to connect the subclasses by vertical lines to a horizontal line, which has a triangle connecting the horizontal line through another vertical line to the superclass. A blank triangle indicates a specialization/generalization with the disjoint constraint, and a filled triangle indicates an overlapping constraint. view more..
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Ans: For our sample database application, consider a UNIVERSITY database that keeps track of students and their majors, transcripts, and registration as well as of the university’s course offerings. The database also keeps track of the sponsored research projects of faculty and graduate students. view more..
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Ans: Recovery from transaction failures usually means that the database is restored to the most recent consistent state just before the time of failure. To do this, the system must keep information about the changes that were applied to data items by the various transactions. view more..
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Ans: Several types of locks are used in concurrency control. To introduce locking concepts gradually, first we discuss binary locks, which are simple, but are also too restrictive for database concurrency control purposes, and so are not used in practice. Then shared/exclusive locks - also known as read/write locks - which provide more general locking capabilities and are used in practical database locking systems. view more..
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Ans: In this section we discuss the concepts of concurrent execution of transactions and recovery from transaction failures. view more..
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Ans: Conceptual modeling is a very important phase in designing a successful database application. Generally, the term database application refers to a particular database and the associated programs that implement the database queries and updates. view more..
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Ans: Data is converted into information, and information is then evaluated and organised so that it can be used purposefully as knowledge. view more..
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Ans: A database system is a collection of interrelated data and a set of programs that allow users to access and modify these data. A major purpose of a database system is to provide users with an abstract view of the data. That is, the system hides certain details of how the data are stored and maintained. view more..
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Ans: In this section we discuss the concepts of concurrent execution of transactions and recovery from transaction failures view more..
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Ans: This chapter discusses techniques for securing databases against a variety of threats. It also presents schemes of providing access privileges to authorized users. view more..
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Ans: A database system provides a data-definition language to specify the database schema and a data-manipulation language to express database queries and updates. view more..
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Ans: Database design mainly involves the design of the database schema. The design of a complete database application environment that meets the needs of the enterprise being modelled requires attention to a broader set of issues. view more..
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Ans: A relational database is based on the relational model and uses a collection of tables to represent both data and the relationships among those data. view more..
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Ans: A relational database is based on the relational model and uses a collection of tables to represent both data and the relationships among those data. view more..
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Ans: A relational database is based on the relational model and uses a collection of tables to represent both data and the relationships among those data. view more..
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Ans: A database system is partitioned into modules that deal with each of the responsibilities of the overall system. The functional components of a database system can be broadly divided into the storage manager and the query processor components. view more..
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Ans: A transaction is a collection of operations that performs a single logical function in a database application. view more..




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