Introduction to Database Security Issues






Frequently Asked Questions

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Ans: The basic structure of an SQL query consists of three clauses: select, from, and where. view more..
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Ans: The set of relations in a database must be specified to the system by means of a data-definition language (DDL). view more..
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Ans: IBM developed the original version of SQL, originally called Sequel, as part of the System R project in the early 1970s. 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: The natural join operation operates on two relations and produces a relation as the result. view more..
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Ans: Reason to rename a relation is a case where we wish to compare tuples in the same relation. view more..
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Ans: SQL permits a variety of functions on character strings. Read to know about them. view more..
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Ans: The company is organized into departments. Each department has a unique name, a unique number, and a particular employee who manages the department. We keep track of the start date when that employee began managing the department. A department may have several locations.  A department controls a number of projects, each of which has a unique name, a unique number, and a single location view more..
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Ans: Entities and Their Attributes. The basic object that the ER model represents is an entity, which is a thing in the real world with an independent existence. An entity may be an object with a physical existence (for example, a particular person, car, house, or employee) view more..
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Ans: A database usually contains groups of entities that are similar. For example, a company employing hundreds of employees may want to store similar information concerning each of the employees. These employee entities share the same attributes, but each entity has its own value(s) for each attribut view more..
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Ans: An entity type DEPARTMENT with attributes Name, Number, Locations, Manager, and Manager_start_date. Locations is the only multivalued attribute. We can specify that both Name and Number are (separate) key attributes because each was specified to be unique view more..
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Ans: There are several implicit relationships among the various entity types. In fact, whenever an attribute of one entity type refers to another entity type, some relationship exists. For example, the attribute Manager of DEPARTMENT refers to an employee who manages the department; the attribute view more..
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Ans: Select clause uses. view more..
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Ans: Entity types that do not have key attributes of their own are called weak entity types. In contrast,regular entity types that do have a key attribute—which include all the examples discussed so far—are called strong entity types view more..
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Ans: If some cardinality ratio or dependency cannot be determined from the requirements, the users must be questioned further to determine these structural constraints view more..
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Ans: The individual entity instances in an entity set and the individual relationship instances in a relationship set. In ER diagrams the emphasis is on representing the schemas rather than the instances. view more..
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Ans: The UML methodology is being used extensively in software design and has many types of diagrams for various software design purposes. We only briefly present the basics of UML class diagrams here, and compare them with ER diagrams view more..
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Ans: we defined the degree of a relationship type as the number of participating entity types and called a relationship type of degree two binary and a relationship type of degree three ternary view more..




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