What characteristic is associated with the database approach to data management?

Ch4: AUDITING DATABASE SYSTEMS

Multiple choice

All of the following are basic data management tasks except: A) data deletion

Data attribution

The task of searching the database to locate a stored record for processing is called: A) data deletion

Data retrieval

Which of the following is not a problem usually associated with the flat-file approach to data management? A) data redundancy

Restricting access to data to the primary user

Which characteristic is associated with the database approach to data management? A) data sharing

Data sharing

Which characteristic is not associated with the database approach to data management? A) the ability to process data

The inability to determine what data is available

The textbook refers to four interrelated components of the database concept. Which of the following is not one of the components? A) the database manag

The conceptual database

Which of the following is not a responsibility of the database management system? A) provide an interface between

Ensure that the internal schema and external schema are consistent

A description of the physical arrangement of records in the database is: A) the internal view

The internal view

Which of the following may provide many distinct views of the database? A) the schema

The user view

Users access the database: A) by direct query By direct query The data definition language: A) identifies, for the database management system, the

identifies, for the database management system, the

The data manipulation language: A) defines the database to the database man

Enables application programs to interact w/ & manipulate the database Which statement is not correct? A query language like SQL: A) is written in a fourth-generati

Requires user familiarity with COBOL

Which duty is not the responsibility of the database administrator? A) to develop and maintain the

To design application programs

In a hierarchical model: A) links between related records are implicit

The way to access data is by following a predefined data path Which term is not associated with the relational database model? A) tuple

Collision

In the relational database model: A) relationships are explicit

Data is presented on two-dimensional tables

In the relational database model all of the following are true except: A) data is presented to users as tables

Only one-to-many relationships can be supported

In a relational database: A) the user's view of the physical database is the same as

Users perceive that they are manipulating a single table Which of the following is not a common form of conceptual database model? A) hierarchical

Sequential

Which statement is false? A) The DBMS is special software that is programmed to know

The DBMS does not control access to the database

All of the following are elements of the DBMS which facilitate user access to the database except: A) query language

Data access language

Which of the following is a level of the database that is defined by the data definition language? A) user view

All are levels or views of the database

An example of a distributed database is: A) partitioned database

partitioned database

Data currency is preserved in a centralized database by: A) partitioning the database

Using a lockout procedure

Which procedure will prevent two end users from accessing the same data element at the same time? A) data redundancy

Data lockout

The advantages of a partitioned database include all of the following except: A) user control is enhanced

Data transmission volume is increased

A replicated database is appropriate when: A) there is minimal data sharing among

There exists a high degree of data sharing and no primary user What control maintains complete, current, and consistent data at all information processing units? A) deadlock control

Concurrency control

There are number of characteristics that distinguish the database approach from the much older approach of programming with files.

For example, one user, the grade reporting office, may keep files on students and their grades. Programs to print a student’s transcript and to enter new grades are implemented as part of the application. A second user, the accounting office, may keep track of students’ fees and their payments. Although both users are interested in data about students, each user maintains separate files— and programs to manipulate these files—because each requires some data not available from the other user’s files. This redundancy in defining and storing data results in wasted storage space and in redundant efforts to maintain common up-to-date data.

The main characteristics of the database approach (feature of database approach) And how it differs from the traditional file system i.e file-processing approach :

We have described each of these characteristics in a separate section.

For example, an application program written in C++ may have struct or class declarations, and a COBOL program has data division statements to define its files. Whereas file-processing software can access only specific databases, DBMS software can access diverse databases by extracting the database definitions from the catalog and using these definitions. The DBMS catalog will store the definitions of all the files shown. Figure 1.3 shows some sample entries in a database catalog. These definitions are specified by the database designer prior to creating the actual database and are stored in the catalog. Whenever a request is made to access, say, the Name of a STUDENT record, the DBMS software refers to the catalog to determine the structure of the STUDENT file and the position and size of the Name data item within a STUDENT record. By contrast, in a typical file-processing application, the file structure and, in the extreme case, the exact location of Name within a STUDENT record are already coded within each program that accesses this data item.

A database typically has many users, each of whom may require a different perspective or view of the database. A view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored. Some users may not need to be aware of whether the data they refer to is stored or derived. A multiuser DBMS whose users have a variety of distinct applications must provide facilities for defining multiple views. For example, one user of the database may be interested only in accessing and printing the transcript of each student; the view for this user is shown in Figure 1.5(a). A second user, who is interested only in checking that students have taken all the prerequisites of each course
for which they register, may require the view shown in Figure 1.5(b).

+

Characteristics of the Database Approach

Ans: Self-describing nature of a database system Insulation between programs and data, and data abstraction Support of multiple views of the data Sharing of data and multiuser transaction processing view more..

+

View of Data

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..

+

Subclasses, Superclasses, and Inheritance

Ans: The specialization relationship may also be referred to as a superclass-subclass relationship. Higher- and lower-level entity sets also may be designated by the terms superclass and subclass, respectively. The person entity set is the superclass of the employee and student subclasses. view more..

+

what is database management system

Ans: A database-management system (DBMS) is a collection of interrelated data and a set of programs to access those data. view more..

+

Database-System Applications

Ans: Databases are widely used in enterprises, banking and finance, universities, airlines, telecommunication, etc. view more..

+

Specialization and Generalization

Ans: Specialization is the process of defining a set of subclasses of an entity type; this entity type is called the superclass of the specialization. We use the term generalization to refer to the process of defining a generalized entity type from the given entity types. view more..

+

Constraints and Characteristics of Specialization and Generalization Hierarchies

Ans: we discuss differences between specialization/generalization lattices (multiple inheritance) and hierarchies (single inheritance), and elaborate on the differences between the specialization and generalization processes during conceptual database schema design. We discuss constraints that apply to a single specialization or a single generalization. view more..

+

Modeling of UNION Types Using Categories

Ans: it is sometimes necessary to represent a single superclass/subclass relationship with more than one superclass, where the superclasses represent different entity types. In this case, the subclass will represent a collection of objects that is a subset of the UNION of distinct entity types. view more..

+

A Sample UNIVERSITY EER Schema, Design Choices, and Formal Definitions

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..

+

Example of Other Notation: Representing Specialization and Generalization in UML Class Diagrams

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..

+

Data Abstraction, Knowledge Representation, and Ontology Concepts

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..

+

Using High-Level Conceptual Data Models for Database Design

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..

+

Using High-Level Conceptual Data Models for Database Design

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..

+

Using High-Level Conceptual Data Models for Database Design

Ans: In this section we discuss the concepts of concurrent execution of transactions and recovery from transaction failures. view more..

+

Using High-Level Conceptual Data Models for Database Design

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..

What are the characteristics of database management system?

What is database approach to data management?

Which of the following characteristics the data in the database?

What are the four main characteristics of the database approach versus the file processing approach?