Chapter 12 BEC
Which one of the following correctly depicts the hierarchy of storage commonly found in computerized databases, from least complex to most complex?
B. Byte, field, record, file.
deadly embrace
also called a deadlock, can be resolved by a DBMS. This situation occurs when two transactions attempt to update a single data element simultaneously. 1) When a deadly embrace occurs, the DBMS selects one of the transactions as the "victim" and releases the data resources it controls so that the other transaction can run to completion. The victim transaction is then restarted and permitted to run.
bit
b. A bit (sometimes thought of as a contraction of "binary digit") is either 0 or 1 (off or on) in binary code. Bits can be strung together to form a binary (i.e., base 2) number
byte
c. A byte is a group of bits. A byte can be used to signify a character (a number, letter of the alphabet, or symbol, such as a question mark or asterisk).
data structures 1.relations. 2. attributes 3. tuples
1. relations-data structures 2. tables columns refereed as attributes 3. rows are called tuples
database management system (DBMS)
A database management system (DBMS) is an integrated set of software tools superimposed on the data files that helps maintain the integrity of the underlying database.
schema
A particular database's design, called its schema, consists of the layouts of the tables and the constraints on entering new records. To a great extent, a DBMS automates the process of enforcing the schema.
record
A record is a group of fields. All the fields contain information pertaining to an entity, e.g., a specific performance of an orchestral work.
Application software
Application software consists of programs that tell the computer what steps the user wants carried out. It may be purchased from vendors or developed internally. 1) Examples of applications found on desktop computers include word processors, spreadsheets, graphics, and small databases. 2) Applications found on dedicated servers are payroll, human resources, purchasing, accounts payable, general ledger, treasury, etc
5. Relational Databases
In the relational database model, the elements of data "relate" to one another in a highly flexible way.
Prototyping
Prototyping is an alternative approach to application development. Prototyping involves creating a working model of the system requested, demonstrating it for the user, obtaining feedback, and making changes to the underlying code.
Third-generation languages
Third-generation languages (many of which are termed procedural languages) consist of English-like words and phrases that represent multiple machine language instructions, making these languages much easier to learn. These languages must be converted to machine language either by compilation (the whole program is converted at once, then executed) or interpretation (the program is converted and executed one line at a time). Third-generation languages have been deployed for decades with tremendous success. The following is a list of some of the better-known ones:
Utility programs
Utility programs, which perform basic functions that are not particular to a certain application, such as file manipulation (copying, deleting, merging, and sorting data files) and file access control
Step 3. Build or Buy
When an organization acquires a new system by purchasing from an outside vendor, contract management personnel oversee the process. The future end-users of the system as well as IT personnel are also involved, drawing up specifications and requirements.
distributed database
meaning one that is stored in two or more physical sites.
A benefit of using computer-aided software engineering (CASE) technology is that it can ensure that No obsolete data fields A. occur in files. B. Users become committed to new systems. C. All programs are optimized for efficiency. D. Data integrity rules are applied consistently.
Answer (D) is correct. CASE is an automated technology (at least in part) for developing and maintaining software and managing projects. A benefit of using CASE technology is that it can ensure that data integrity rules, including those for validation and access, are applied consistently across all files.
Object-oriented programming (OOP)
-combines data and the related procedures into an object. Thus, an object's data can be operated on only within the object. 2) The basic concepts of object-oriented programming are class and inheritance. Programs are written by describing the creation and interaction of classes. One class of objects can inherit the characteristics of a more general class. Thus, a basic advantage of object-oriented programming is that the code is reusable.
First-generation languages
. First-generation languages (also called machine languages) are written in binary code (a combination of ones and zeros; see Subunit 12.2) unique to each type of computer. Because they are in binary code, first generation languages are understood directly by the computer and require no translation process.
Two vital parts of any DBMS are 1. Data definition language 2. data manipulation language
1) A data definition language, which allows the user to specify how the tables will look and what kinds of data elements they will hold. 2) A data manipulation language, with which the DBMS retrieves, adds, deletes, or modifies records and data elements.
Step 5. The phases and component steps of the traditional SDLC
1) A proposal for a new system is submitted to the IT steering committee describing the need for the application and the business function(s) that it will affect. 2) Feasibility studies are conducted to determine a) What technology the new system will require b) What economic resources must be committed to the new system c) How the new system will affect current operations 3) The steering committee gives its go-ahead for the project.
Third-generation languages examples 1) COBOL (COmmon Business Oriented Language) 2) BASIC 3) C and C++ 4) Java is a high-level
1) COBOL (COmmon Business Oriented Language) was designed in 1959 to be easy to read and maintain, and the standard has been extensively revised and updated over the years. Vast quantities of lines of COBOL are still in use. 2) BASIC (Beginner's All-purpose Symbolic Instruction Code) was developed to teach programming but is not used in large business application processing. Visual BASIC provides a graphical user interface to develop Microsoft Windows applications from code written in BASIC. 3) C and C++ have been very popular languages since their introduction. C++ enhances C by adding features like support for object-oriented programming. 4) Java is a high-level, object-oriented programming language developed by Sun Microsystems that, among other things, is used to write programs embedded in World Wide Web documents. It is designed to allow a user to download from a network only the data and the part of an application needed to perform a given task. When processing is complete, the data and software are erased.
1) Cardinality
1) Cardinality refers to the boundaries of the relationship between certain data elements. a) For example, the Order Table above cannot contain a record where the quantity ordered has a value of 0 or less nor have a value greater than 500.
Step 1. Organization Needs Assessment
1) Determine whether current systems support organizational goals 2) Determine needs unmet by current systems 3) Determine capacity of current systems to accommodate projected growth 4) Propose path for information systems deployment to achieve organizational goals within budgetary constraints
replication, or snapshot
1) In the replication, or snapshot, technique, the DBMS duplicates the entire database and sends it to multiple locations. Changes are periodically copied and similarly distributed.
1) 4th gen The best-known nonprocedural language is Structured Query Language (SQL),
1) The best-known nonprocedural language is Structured Query Language (SQL), which enables the user to read, update, reorganize, and report on data contained in a relational database [see item 2.b.2) on page 8].
operating system
1) The operating system, which is the "traffic cop" of any computer system a) The operating system negotiates the conversation between the computer's hardware, the application the user is running, and the data that the application is working with. b) Examples are Linux and Windows.
2) Generalized audit software (GAS),
2) Generalized audit software (GAS), also known as computer-assisted audit techniques (CAAT), involves the use of computer software packages that may allow not only parallel simulation, but also a variety of other processing func¬tions, such as extracting sample items, verifying totals, developing file statistics, and retrieving specified data fields. Audit Command Language (ACL®) and Interactive Data Extraction and Analysis (IDEATM) are the leading CAAT packages.
fragmentation, or partitioning
2) In the fragmentation, or partitioning, method, specific records are stored where they are most needed. For example, a financial institution may store a particular customer's data at the branch where (s)he usually transacts his/her business. If the customer executes a transaction at another branch, the pertinent data are retrieved via communications lines.
2) Referential integrity
2) Referential integrity means that for a record to be entered in a given table, there must already be a record in some other table(s). a) For example, the Order Table above cannot contain a record where the part number is not already present in the Parts Table.
Hypertext markup language (HTML)
3) Hypertext markup language (HTML) is the authoring software language commonly used to create and link websites. Its key features are formatting the content of a web page and hyperlinking, which allows direct navigation to related web pages.
4) Extensible markup language (XML)
4) Extensible markup language (XML) is an open standard usable with many programs and platforms. Unlike HTML, XML uses codes that are extensible, not fixed, so if an industry can agree on a set of codes, software for that industry can be written by incorporating those codes. For example, XML allows the user to label the UPC (uniform product code)
5) Extensible business reporting language (XBRL)
5) Extensible business reporting language (XBRL) is the specification developed by an AICPA-led consortium for commercial and industrial entities that report in accordance with U.S. GAAP. It is a variation of XML that is expected to decrease the costs of generating financial reports, reformulating information for different uses, and sharing business information using electronic media.
field
A field is a group of bytes. The field contains a unit of data about some entity, e.g., a composer's name.
file
A file is a group of records. All the records in the file contain the same pieces of information about different occurrences, e.g., performances of several orchestral works.
To trace data through several application programs, an auditor needs to know what programs use the data, which files contain the data, and which printed reports display the data. If data exist only in a database system, the auditor could probably find all of this information in a A. Data dictionary. B. Database schema. C. Data encryptor. D. Decision table.
Answer (A) is correct. The data dictionary is a file (possibly manual but usually computerized) in which the records relate to specified data items. It contains definitions of data items, the list of programs used to process them, and the reports in which data are found. Only certain persons or entities are permitted to retrieve data or to modify data
The process of learning how the current system functions, determining the needs of users, and developing the logical requirements of a proposed system is referred to as A. Systems maintenance. B. Systems analysis. C. Systems feasibility study. D. Systems design.
Answer (B) is correct. A systems analysis requires a survey of the existing system, the organization itself, and the organization's environment to determine (among other things) whether a new system is needed. The survey results determine not only what, where, how, and by whom activities are performed but also why, how well, and whether they should be done at all. Ascertaining the problems and informational needs of decision makers is the next step. The systems analyst must consider the entity's key success variables (factors that determine its success or failure), the decisions currently being made and those that should be made, the factors important in decision making (timing, relation to other decisions, etc.), the information needed for decisions, and how well the current system makes those decisions. Finally, the systems analysis should establish the requirements of a system that will meet user needs.
Fourth-generation computer programming languages are represented by A. Procedure-oriented languages, which describe processing procedures. B. Query languages, which allow direct access to a computer database. C. Symbolic languages, which allow direct access to a stored database. D. Machine languages, which describe processing procedures.
Answer (B) is correct. Fourth-generation languages are intended to simplify programming. They are not intended to express a procedure as a specific algorithm. These interactive, English-like languages permit the user to describe the problem to and receive guidance from the computer. Query languages are most often used with databases. They permit reading and reorganization of data but not its alteration.
An important function of a database administrator is A. Reviewing database output for errors and omissions. B. Scheduling daily database operations. C. Redefining and restructuring the database. D. Evaluating internal controls for hardware.
Answer (C) is correct. The database administrator is the individual with overall responsibility for developing and maintaining the database. (S)he uses data definition language to define, create, redefine, and restructure the database. The database administrator also establishes controls over the integrity of the database
One advantage of a database management system (DBMS) is A.Each organizational unit takes responsibility and control for its own data. B.The cost of the data processing department decreases as users are now responsible for establishing their own data handing techniques. C. A decreased vulnerability as the database management system has numerous security controls to prevent disasters. D. The independence of the data from the application programs, which allows the programs to be developed for the user's specific needs without concern for data capture problems.
Answer (D) is correct. A fundamental characteristic of databases is that applications are independent of the database structure; when writing programs or designing applications to use the database, only the name of the desired item is necessary. Programs can be developed for the user's specific needs without concern for data capture problems.
Which of the following programming languages supports object-oriented programming? A. Pascal. B. FORTRAN. C. C. D. C++.
Answer (D) is correct. C++ was originally called "C with classes." As the name implies, C is its foundation. Classes provide a means of encapsulating the logical entities used by the program (which ordinarily represent the program's data) into a well-organized, modular format that is easy to reuse and maintain. Through a process called inheritance, new classes can be derived from existing classes by adding new elements to the existing class design. C++ was specifically designed with these features in mind. Because code segments can
The primary purpose of a database system is to have a single storage location for each A. File. B. Record. C. Database. D. Data item.
Answer (D) is correct. Data organized in files and used by the organization's various applications are collectively known as a database. In a database system, storage structures are created that render the applications independent of the physical or logical arrangement of the data. Each data item has a standard definition, name, and format, and related items are linked by a system of pointers. The programs therefore only need to specify data items by name, not by location. A database management system handles retrieval and storage. Because separate files for different applications are unnecessary, data redundancy (multiple storage locations for a data item) can be substantially reduced.
In which each data record has a pointer field containing the address of the next record in the list. A. In which an index of record pointers of some of the file attributes are maintained B. in a list. That uses an algorithm to convert a record key into a storage address to assist with later retrieval. C. In which records are stored sequentially in a direct access file and organized by a primary key stored in an index record.
Answer (D) is correct. ISAM stores records sequentially in a direct access file that is organized by a primary key kept in an index record. The index contains pointers (addresses) to the records in the file, but the records themselves do not contain pointers. The virtue of ISAM is that it permits sequential processing of large numbers of records while providing for occasional direct access
Writing computer programs in binary code would be tedious. A language allowing symbolic codes to be substituted on a one-to-one basis for binary operating codes and memory addresses is referred to as
Assembly language. languages use language-like symbols to replace binary code. One assembly language instruction ordinarily corresponds to one machine language instruction. A program written in a language other than machine language is a source program
Computer-aided software engineering (CASE)
Computer-aided software engineering (CASE) applies the computer to software design and development. 2) Thus, CASE facilitates the creation, organization, and maintenance of documentation and permits some automation of the coding process.
An advantage of a data dictionary is that its use
Facilitates complete identification of instances of A. use of data items Answer (A) is correct. The data dictionary is a file (possibly manual but usually computerized) in which the records relate to specified data items. It contains definitions of data records and files, the list of programs used to process them, and the reports in which the data are found. Only certain persons or entities are permitted to retrieve data or to modify data items. Accordingly, these access limitations are also found in the data dictionary. Maintaining data integrity is thus a function of a data dictionary.
Fourth-generation languages
Fourth-generation languages (also called problem-oriented or nonprocedural languages) provide still further simplification of programming. These interactive, English-like languages permit a nonspecialized user to describe the problem to, and receive guidance from, the computer instead of specifying a procedure.
Fourth-generation computer programming languages are represented by
Fourth-generation languages are intended to simplify programming. They are not intended to express a procedure as a specific algorithm. These interactive, English-like languages permit the user to describe the problem to and receive guidance from the computer.
The indexed sequential access method (ISAM) is an approach to file organization
ISAM stores records sequentially in a direct access file that is organized by a primary key kept in an index record. The index contains pointers (addresses) to the records in the file, but the records themselves do not contain pointers
Step 6 Design
Logical design consists of mapping the flow and storage of the data elements that will be used by the new system and the new program modules that will constitute the new system. a) Data flow diagrams (DFDs) and structured flowcharts are commonly used in this step. b) Some data elements may already be stored in existing databases. Good logical design ensures that they are not duplicated.
Rapid application development (RAD)
Rapid application development (RAD) is a software development process involving iterative development, the construction of prototypes, and the use of CASE tools 1) The RAD process usually involves compromises in usability, features, and/or execution speed; increased speed of development occurs through rapid prototyping, virtualization of system related routines, and other techniques. However, there is usually decreased end-user utility.
Second-generation languages
Second-generation languages (also called assembly or symbolic languages) use mnemonic symbols to represent groups of binary ones and zeros. Assembly languages must be converted to machine languages in order for the computer to understand them.
key.
Some field or combination of fields on each record is designated as the key. The essence of a key is that it contains enough information to uniquely identify each record, i.e., there can be no two records with the same key.
Step 7 Development
The actual program code and database structures that will be used in the new system are written. 2) Testing is the most crucial step of the process. a) The programmers thoroughly test each new program module of the system, both alone and in concert with other modules.
data dictionary
The data dictionary contains the physical and logical characteristics of every data element in a database. 1) The data dictionary includes, for example, the name of the data element (e.g., employee name, part number), the amount of space required to store the data element (in bytes), and what kind of data is allowed in the data element (e.g., alphabetic, numeric).
4. Network Databases
The network database model allowed child records to have multiple parents. This was an attempt to make queries more efficient, but the huge number of cross-references inherent in this structure made maintenance far too complex.
Implementation Four strategies for converting to the new system can be used 1. parallel operation 2. cutover conversion 3. pilot conversion 4. phased conversion
a) With parallel operation, the old and new systems both are run at full capacity for a given period. b) With cutover conversion, the old system is shut down and the new one takes over processing at once. c) Under pilot conversion, one branch, department, or division at a time is fully converted to the new system. e) In some cases, phased conversion is possible. Under this strategy, one function of the new system at a time is placed in operation.
Step 2. Business Process Design
a. A business process is a flow of actions performed on goods and/or information to accomplish a discrete objective. 1) Examples include hiring a new employee, recruiting a new customer, and filling a customer order.
program change controls
a. Over the life of an application, users are constantly asking for changes. The process of managing these changes is referred to as systems maintenance, and the relevant controls are called program change controls. b. Once a change to a system has been approved, the programmer should save a copy of the production program in a test area of the computer, sometimes called a "sandbox."
Step 4. Systems Development Life Cycle (SDLC)
a. The systems development life-cycle approach is the traditional methodology applied to the development of large, highly structured application systems. A major advantage of the life-cycle approach is enhanced management and control of the development process.
Which of the following programming languages supports object-oriented programming?
process called inheritance, new classes can be derived from existing classes by adding new elements to the existing class design. C++ was specifically designed with these features in mind. Because code segments can be reused in other programs, the time and cost of writing software is reduced. [7] Gleim #: 12.1.7 -- Source: Publisher, adapted Structured Query Language (SQL) is best defined as a A. Programming language in which UNIX is written. B. Report generator used to produce customized business reports. C. Programming language in which many business applications are written. Data manipulation language used in conjunction with a database management system (DBMS). D.
The project initiation phase includes
promptly informing managers and employees about the project, assembling the project team (possibly including systems analysts, programmers, accountants, and users), training selected personnel to improve necessary skills and enhance communication among team members, and establishing project controls (e.g., by implementing a project scheduling technique such as PERT). Preparing the project proposal is a part of the project definition phase, as are conducting feasibility studies, determining project priority, and submitting the proposal for approval
