Implementation and maintenance

After the plan for an information system is approved, it’s time to start building it. The implementation phase can include: purchase and install hardware and/or software, create applications, test applications, finalize documentation, train users, convert data, convert to new system.

Application testing is performed in three ways: unit testing, integration testing, and system testing. Unit testing and integration testing are usually performed in a test area. A test area might to be located in an isolated section of storage on the computer system that runs the organization’s regular information system, or might be located on an entirely separate computer system. When a problem is discovered during unit testing or integration testing, the team must track down the source of the problem and correct it. Unit testing and integration testing are then repeated to make sure the problem is corrected, and no new problems were introduced when the original problem was fixed.

The data for a new information system might exist in card files, file folders, or an old information system. This data must be loaded into the new system - a process called “data conversion”. When converting data from a manual system to a computer system, the data can be typed or scanned electronically into the appropriate storage media. When converting data from an existing computer system to a new system, a programmer typically writes conversion software to read the old data and convert it into a format that is usable by the new system.

System conversion refers to the process of deactivating an old information system and activating a new one. It is also referred to as “cutover” or “go live”. There are several strategies for converting to a new system. They are a direct conversion, a parallel conversion, a phased conversion, a pilot conversion.

A new or upgraded information system undergoes a final test called acceptance testing. It includes the use of real data to demonstrate that the system operates correctly under normal and peak data loads. The term “maintenance phase” is a bit misleading because it seems to imply that the information system is maintained in a static state. On the contrary, during the maintenance phase, an information system is likely to undergo many changes to meet an organization’s needs. They can include the following: upgrades to operating system and commercial software, user interface revisions to make the system easier to use, application software revisions to fix bugs and add features, hardware replacements to enhance performance, security upgrades.

To combat an escalating number of viruses, worms, Denial of Service attacks, and intrusions, security has become a top priority for the maintenance phase of an information system’s life cycle. Maintaining security is an ongoing activity. A system operator and a systems programmer are responsible for system maintenance. Even after in-depth training, employees sometimes forget procedures or have difficulty when they encounter a new set of circumstances. Many organizations establish a help desk to handle end-user problems. For example, suppose you encounter a problem with an update procedure and call the help desk. The help desk technician begins to troubleshoot the problem and soon realizes that it is caused by a programming error not caught during system testing. This bug is recorded in a “bug report” that is routed to the programming group, which can determine its severity and take steps to fix it.

 

Comprehension check. Match the beginnings of the sentences in the first column with the endings in the second.

1. Unit testing and integration testing are 2. When a problem is discovered during unit testing or integration testing 3. System conversion refers 4. When converting data from an existing computer system to a new system 5. A system operator and a systems programmer are 6. The help desk technician begins

a) responsible for system maintenance. … a programmer typically writes. b) conversion software to read the old data and convert it into a format that is usable by the new system. c) … usually performed in a test area. d) … the team must track down the source of the problem and correct it. e) … to troubleshoot the problem and soon realizes that it is caused by a programming error not caught during system testing. f) … to the process of deactivating an old information system and activating a new one.

 

Vocabulary practice

1. Put the letters in the following words into the correct order.

sienncovor ruvis sinrution shoyubtleroot cascumcriten agerost

 

2. Fill in the blanks choosing from the variants given.

1. Application testing is performed in three ways: integration testing, unit testing and ….

a) data testing b) program testing c) system testing

2. When a problem is discovered during unit testing or integration testing, the team must … the source of the problem and correct it.

a) investigate b) produce c) include

3. Unit testing and integration testing are repeated to make sure the problem is ….

a) activated b) converted c) solved

4. System conversion refers to the process of deactivating an old … system and activating a new one.

a) information b) operating c) support

5. An information system is likely to undergo many … to meet a company’s needs.

a) changes b) formats c) systems

6. Many organizations establish a help desk … end-user problems.

a) to divide b) to manage c) to enlarge

7. The help desk technician begins to troubleshoot the problem and soon … that it is caused by a programming error not caught during system testing.

a) forgets b) repeats c) understands

3. Match the beginnings and the endings of the instructions/steps given and put them into correct order.

 

1. Create debugger as a system software that helps programmers 2. After that write the specifications and design the computer system and the methods for the information system 3. Write the program in a specific programming language, that specifically refers 4. Depending on the organization and its size, the systems analyst’s tasks are 5. Next step is to interview the people who will be using the system 6. With the help of testing and acceptance, make sure the system works properly and 7. Then determine which people and what kind of software, hardware, and monetary resources are 8. Keep system working properly and, if business procedures or conditions are changed,

a) to determine their needs, problems, and expectations. b) to solve the problem. c) turn it over to the users with accompanying training, as necessary. d) to writing source code. e) necessary or available to solve the problem. f) to analyze the problem to be solved, the data to be input, the expected output, and other system considerations. g) identify errors. h) improve them.

 

4. Fill in the gaps in the text.

During the ___ phase of the SDLC, the project team supervises the technicians who set up new hardware, install programming languages and other application ___ tools, create and test applications, and customize software. The team also finalizes the system documentation and trains users. In this phase, three types of testing ensure that new software works correctly. ___ testing is performed on each module, and then ___ testing is performed to make sure that all of the modules work together correctly. ___ testing ensures that the software components work correctly on the hardware and with other, perhaps older, elements of the information system.

When application testing is complete, data is converted from the old system to the new one, users are trained, and the new system goes live. Four types of information system “go live” conversions are possible. At the end of the conversion process, the information system undergoes a final test called ___ testing, designed to assure the system’s owner that the new system works as specified.

After installation, an information system enters the ___ phase of its life cycle.

Speaking. Discuss the following questions.

1. Does a new information system typically require new hardware?

2. What the next step in the implementation phase?

3. What is application testing?

4. What documentation does the project team create during the implementation phase?

5. How do employees learn how to use the new information system?

6. How does a business switch from the old information system to the new system?

7. What happens during the maintenance phase?

8. How important is system security during this phase?

9. Who is responsible for system maintenance?

10. Why do maintenance activities include user support?

 

Critical thinking. Read the article and express your opinion on the problem.

Online Voting

 

The idea of online voting surfaced years ago as the Internet gained popularity. The term online voting usually refers to a remote voting system that allows voters to cast their ballots from any computer connected to the Internet.

Because of its advantages, online voting has the potential to attract net-savvy young voters who historically have voted in lower numbers than other segments of the population. It also simplifies the voting process for elderly and homebound voters. The convenience of online voting might also increase participation in local elections.

Online voting has the potential to decrease the number of ballots that are invalidated because of procedural problems, such as failing to completely punch out the “chad” on a ballot card, or checking more than one candidate on a paper ballot. Voting software can prevent voters from erroneously selecting more than one candidate and make sure that voters can revise their selections without invalidating their ballots.

Although there are plenty of supporters of this form of elections there are lots of opponents because of the risk of some technological issues with Internet security.

In addition to them online voting opponents have concerns about voter fraud and privacy.

For democracy to function properly, its citizens should be confident that the electoral system is honest and works. Online voting presents some sticky technological and social challenges. Although these challenges exist, secure technologies for online banking and e-commerce are working, so shouldn’t it be possible to design an online voting system that's secure enough to conduct our elections?

 

What do you think?

1. Would you prefer online voting to voting at a polling place?

2. Should online voting be available only to specific groups of people who currently have trouble reaching polling places?

3. What technical issues can online voting face and how to solve them?

 

Projects. Perform the project given.

 

1. Form a group of two to five students as the project team for a systems development project. Elect one person as the team leader, who will assign tasks to each group member. Your team’s mission is to complete the planning phase for a systems development project and produce a Project Development Plan. The first task is to identify and briefly describe an information system at school, work, or local business that needs improvement. The second task is to make a list of problems and opportunities that exist in that system. The third task is to make a list of tasks your team would perform, design, construct, and implement a new information system. Finally, incorporate all your findings into a document that would serve as the Project Development Plan. Submit this plan to your instructor, who might provide additional directions for your group work and report format.

2. Create 10 rules for an expert system that pertains to your career field. To complete the assignment, think of a set of simple decisions that someone on the job might be required to perform. For example, a loan officer might be required to make a quick evaluation of a borrower, an auto mechanic might be required to figure out what various tapping noises mean, or a fitness instructor might be required to recommend the best type of fitness class for clients. Make a list of 10 rules that would help make the decision. The rules should be in the format IF…THEN…Submit your rules to your instructor.

 

Final test. Do the tasks in the following test.

 

1. In the analysis phase, the project team determines how the new information system will meet the requirements. (True/False)

2. A … tool is a software application that is designed for documenting system requirements, diagramming current information systems, scheduling development tasks and developing computer programs.

3. The process of planning and building a new information system is referred to as systems … and design.

4. The goal of the…phase is to produce a list of requirements for a new or revised information system.

5. A Project Development Plan typically must be approved by the management before a project proceeds beyond the planning phase. (True/False)

6. In an information system context, a … is an exchange between two parties that is recorded and stored in a computer system.

7. Generally most transaction processing systems provide managers with detail reports that contain all the information needed to understand and analyze data. (True/False)

8. A transaction …- system provides a way to process, store, display, modify, or cancel transactions.

9. During the … phase, the project team supervises the tasks necessary to construct the new information system.

10. If you have a question about the information system you are using, the first step to finding the answer is to call the help desk. (True/False)

11. In the … phase, the project team identifies potential solutions, evaluates these solutions, and then selects the best solution.

12. If a project- team selects turnkey solution the next step would be to have the team’s system analysts create a set of application specifications. (True/False)

13. … processing using client/server or peer-to-peer architecture provides high level processing power at a low cost.

14. Which of the following documents ask a vendor both to recommend hard ware and software for an information system solution and to provide the vendors qualifications to implement the solution.

a) request for quotation c) request for solution

b) request for qualifications d) none of the above

15. Which type of transaction processing systems collects and holds a group of transactions for processing until the end of a day or a pay period.

a) online processing c) group processing

b) batch processing d) rollback processing

16. Unit testing is normally performed in a test area. (True/False)

17. Which phase of an SDLC is usually the most expensive?

18. The analysis phase concludes when the System Requirement Report is written. (True/False)

19. An expert system uses fuzzy logic to deal with imprecise data by asking for a level of confidence with an DLTP system, if one step fails during the transaction, the record will … to their original state.

20. All of the following activities take place during the implementation phase EXCEPT.

a) purchasing and installing software c) purchasing and installing software

b) creating applications d) testing applications

 

Unit 7. DATABASES

Text A

Reading. Read the text and try to guess the meaning of the words in bold. Check your variants in the dictionary.

 

FILE AND DATABASE CONCEPTS

In the broadest definition, a database is a collection of information. Today, databases are typically stored as computer files. The tasks associated with creating, maintaining, and accessing the information in these files are referred to as data management, file management, or database management. The basic element of a structured file is a field. It contains the smallest unit of meaningful information. Each field has a unique field name that describes its contents. For example, in the Vintage Music Shop database, the field name Album Title describes a field containing the name of an album, such as Hard Day’s Night. A field can be variable length or fixed length. A variable-length field is like an accordion – it expands to fit the data you enter, up to some maximum number of characters. A fixed-length field contains a predetermined number of characters (bytes). The data you enter in a fixed-length field cannot exceed the allocated field length. Moreover, if the data you enter is shorter than the allocated length, blank spaces are automatically added to fill the field.

In the world of computing, a record refers to a collection of data fields. Computer databases typically display records as rows in a table or as forms. Each kind of record is referred to as a record type. It is usually shown without any data in the fields. A record that contains data is referred to as a record occurrence, or simply a record.

A structure file that contains only one record type is often referred to as a flat file. Flat files can be used to store simple data, such as names and addresses. In contrast, a database can contain a variety of different record types. A key characteristic of a database is its ability to maintain relationships do that data from several record types can be consolidated or aggregated into essentially one unit for data retrieval and reporting purposes. In database jargon, a relationship is an association between data that’s stored in different record types. For example, Vintage Music Shop’s Customers record type is related to the Orders record type because customers place orders.

An important aspect of the relationship between record types is cardinality. Cardinality refers to the number of associations that can exist between two record types. When one record is related to many records, the relationship is referred to as a one-to-many relationship. A many-to-many relationship means that one record in a particular record type can be related to many records in another record type, or vice versa. The relationship between record types can be depicted graphically with an entity-relationship diagram (sometimes called an “ER diagram” or “ERD”).

Several database models exist. Some models work with all the relationships described earlier in this section, whereas other models work with only a subset of the relationships. The four main types of database models in use today are hierarchical, network, relational, and object oriented. The simplest database model arranges record types as a hierarchy. In a hierarchical database, a record type is referred to as a node or “segment”. The top node of the hierarchy is referred to as the root node. Nodes are arranged in a hierarchical structure as a sort of upside-down tree. A parent node can have more than one child node. But a child node can have only one parent node.

The network database model allows many-to-many relationships in addition to one-to-many relationships. Related record types are referred to as a network set, or simply a “set”. A set contains an owner and members. An owner is similar to a parent record in a hierarchical database. A member is roughly equivalent to a child record. The most popular database model today is a relational database. It stores data in a collection of related tables. Each table (also called a “relation”) is a sequence, or list, of records. All the records in a table are of the same record type. Each row of a table is equivalent to a record as is sometimes called a tuple. Each column of the table is equivalent to a field, sometimes called an attribute. Relationships can be added, changed, or deleted on demand. An object-oriented database stores data as objects, which can be grouped into classes and defined by attributes and methods. A class defines a group of objects by specifying the attributes and methods this objects share. The attributes for an object are equivalent to fields in a relational database. A method is any behavior that an object is capable of performing. There is no equivalent to a method in a non-object-oriented database.

 

Comprehension check. Mark the following statements as True or False.

 

1. The field is a basic element of a structured file.

2. The field contains the biggest unit of meaningful information.

3. The length of a field is always fixed.

4. Simple data, such as names and addresses, can be stored in flat files.

5. Every relation is a sequence, or list, of records.

6. Relationships can be changed or deleted on demand.

 

Vocabulary practice

1. In the text, find the synonyms to the given words.

a node important several typically to perform to comprise

2. Fill in the blanks choosing from the variants given.

1. The most popular database model today is a … database.

a) relational b) object-oriented c) non-object

2. The data you enter in a … field cannot exceed the allocated field length.

a) fixed-length b) variable-length

3. All the records in a table are of the same record ….

a) group b) type c) set

4. The simplest database model arranges record types as a ….

a) hierarchy b) column c) relation

5. Each field has a … field name that describes its contents.

a) unique b) unusual c) unknown

6. All the records in a table are of the … record type.

a) same b) different c) simple

 

3. Make two-word combinations using the words in columns and then fill in the gaps in the following sentences.

A: non-object-oriented B: type

a many-to- many relationship

record database

flat length

simple data

allocated file

 

1. Any kind of record is referred to as a ….

2. Flat files can be used to store …, such as names and addresses.

3. Moreover, if the data you enter is shorter than the …, blank spaces are automatically added to fill the field.

4. There is no equivalent to a method in a ….

5. A structure file that contains only one record type is often referred to as a ….

6. … means that one record in a particular record type can be related to many records in another record type, or vice versa.

 

4. Fill in the gaps in the text.

Computer databases evolved from manual file processing technology in which data is stored in a single ___ file that uses a uniform format for every item the file contains. A ___ holds the smallest unit of meaningful information. A series of data fields forms a ___, which stores data about one entity – a person, place, thing, or event.

Each kind of record is referred to as a record type. A record that contains data is sometimes referred to as a record ___. A ___ file contains only one record type. In contrast, a ___ can contain a variety of different record type.

 

Speaking. Discuss the following questions.

1. What is a database?

2. What is the basic element of a structured file?

3. What is a record?

4. What is involved in defining the structure for records in a file?

5. What are relationships?

Text B

Reading. Read the text and try to guess the meaning of the words in bold. Check your variants in the dictionary.

DATA MANAGEMENT TOOLS

Data Management Software

The simplest tools for managing data are software packages dedicated to a specific data management task, such as keeping track of appointments or managing your checking account. You can purchase these tools or download them from Internet. Although these tools are easy to use, they don’t generally allow you to create new record types because the new record types are predefined. Most spreadsheet and word processing software packages feature simple tools that allow you to specify fields, enter data and manipulate it. For example, Microsoft Excel allows you to sort records, validate data, search for records, perform simple statistical functions, and generate graphs based on the data. Such simple file management tools are popular for individuals who want to maintain flat files that contain hundreds, not thousands, of records. To create your own data management software it is possible to simply enter data as an ASCII text file, and then use a programming language to write routines to access that data.

 

Database Management Systems

The term DBMS (Database Management System) refers to software that is designed to manage data stored in a database. Each DBMS typically specializes in one of the four database models, but some DBMS software offers versatility by dealing with a variety of models and data. An XML DBMS, for example, is optimized for handling data that exists in XML format. An OODBMS (object-oriented database management system) is optimized for an object-oriented database model, allowing you to store and manipulate data classes, attributes, and methods. Database client software allows any remote computer or network workstation to access data in a database.

 

Databases and the Web

The Web provides an opportunity for many people to gain access to data from multiple locations. The simplest way to provide Web access to database is converting a data base report into a HTML document, which can be displayed as a Web page by a browser. In several situations, such as e-commerce, it is important for people to use a browser to add or update records in a database. For example, the process of ordering merchandise at Vintage Music Shop creates a new order record, changes the In Stock field in the Albums table, and creates a customer record for first-time customers. These dynamic database updates require an architecture similar to that used for dynamic Web publishing, plus the use of forms. A form usually exists on a Web server, which sends the form to your browser. Several tools, including ASP, CGI, and PHP, help you create server-side programs.

XML Documents

XML is a markup language that allows field tags, data, and tables to be incorporated into a Web document. It was developed in response to several deficiencies that became apparent as HTML gained widespread use. For example, suppose you are interested in speeches given by Martin Luther King, Jr. Entering his name in a search engine produces thousands of entries, including MLK biographies, streets and schools named after a famous civil rights leader, historic locations relating to the civil rights movement and so on. XML provides tags that can bу embedded in a XML document to put data in context.

As you can see, many techniques exist for storing, accessing, and displaying the data from the databases. Sometimes more than one tool has the potential to work for a specific application. Now that you’ve had an introduction to the options, you should be able to evaluate when and how to use them.

Comprehension check. Mark the following statements as True or False.

 

1. Many techniques exist for storing, accessing, and displaying the data from the databases.

2. The Web provides an opportunity for a limited number of people to gain access to data from multiple locations.

3. Simple file management tools are popular for individuals who want to maintain files that contain thousands of records.

4. The term DBMS (Database Management System) refers to software that is designed to manage data stored in a database.

5. Microsoft Excel doesn’t allow you to sort records, validate data, search for records, perform simple statistical functions, and generate graphs based on the data.

6. XML is a markup language that allows field tags, data, and tables to be incorporated into a Web document.

 

Vocabulary practice

1. In the text find the opposites to the given words.

civil sometimes simple purchase allow unknown

 

2. Fill in the blanks choosing from the variants given.

1. Most spreadsheet and word processing software (sets, packages, collections) feature simple tool that allow you to specify fields, enter data and manipulate it.

2. As you can see, many techniques (are existing, exist, have been existed) for storing, accessing, and displaying the data from the databases.

3. For example, Microsoft Excel (to allow, is allowing, allows) you to sort records, validate data, search for records.

4. XML (were, is, have been) a markup language that allows field tags, data, and tables to be incorporated into a Web document.

5. Now that you (have had, had, has had) an introduction to the options, you should be able to evaluate when and how to use them.

6. Many (methods, ways, techniques) exist for storing, accessing and displaying the data from the databases.

 

3. Make three-word combinations using the words in the columns and then fill in the gaps in the following sentences.

A: address B: client C: software

System management task

database book Database

data management software

database Management information

data server software

 

1. The simplest tools for managing data are soft packages dedicated to a specific ….

2. The term DBMS … refers to software that is designed to manage data stored in a database.

3. Simple tools that easily store … might not be suited for managing a worldwide airline reservation system.

4. To create your own … it is possible to simply enter data as an ASCII text file.

5. … is designed to manage billions of records and lots of transactions every second.

6. … allows any remote computer or network workstation to access data in a database.

 

4. Fill in the gaps in the text.

 

The data in a database can be ___ over the Web. A simple process called ___ Web publishing converts a database report into an HTML document, which can be displayed by a browser. More sophisticated ___ Web publishing produces data from a database on demand. HTML forms and XForms not only provide search capabilities, but can also be used to add or modify data in a ___ with a Web browser. ___ documents provide a Web-based data management tool that uses special __ as field names within a document.

 

Speaking. Discuss the following questions.

 

1. Are simple data management tools available?

2. Can you create your own data management software?

3. What kinds of tools are specially designed for creating and manipulating databases?

4. Is it possible to access a database over the Web?

 

Text C

Pre-reading task. Match the meaning of the following English words with the Russian equivalents.

1. conversion routine а) избыточность данных

2. data redundancy b) порядок сортировки

3. BLOB c) индекс базы данных

4. variable-length field d) конверсионная подпрограмма

5. primary key e) первичный ключ

6. sort order f) целочисленный тип данных

7. validation rule g) большой двоичный объект

8. fixed-length field h) поле неподвижной длины

9. integer data type i) правило ратификации

10. database index j) поле переменной длины

Reading. Read the text and try to guess the meaning of the words in bold. Check your variants in the dictionary.

DATABASE DESIGN

The key to an effective database is its initial design. In a well-designed database, data can be flexibly manipulated to produce timely, meaningful, and accurat e information for decision making. Bad database design can lead to messy database, lost records, and inaccurate data. The goal of database design is to store information so that it easy to access and maintain, but concise enough to take up as little disk space as possible.

The term database structure refers to the arrangement of fields, tables, and relationships in a database. The first step in structuring a relational database is to determine what data must be collected and stored. To do so, a database designer might begin by consulting users and studying the current filing system to compile a list of available data as well as any additional data necessary to produce on-screen output or printed reports.

After the designer determines what data to store, the next step is to organize that data into fields. It is usually easy to break data into fields just by using common sense and considering how people might want to access the data. Any data that people would to search for, sort on, or use in a calculation should be in its own field. The treatment of first and last name illustrates the concept of breaking data into fields. A database designer could define a field called Name to hold an entire customer’s name. With the entire name in one field, however, the database would not be able to access individual parts of the name, making it difficult to alphabetize customers by last name or to produce a report in which names appear in one field. That’s why the last names are stored in a different field than first names.

Although two people might have, for example, the same name or two paychecks might contain the same amount, a computer must have some way to differentiate between records. A primary key is a field that contains data unique to a record.

The data that can be entered into a field depends on the field’s data type. From a technical perspective, data type specifies the way data is represented on the disk and in RAM. From a user perspective, the data type determines the way data can be manipulated. When designing a database, each field is assigned a data type. Data can be broadly classified as numeric or character. Character data contains letters, numerals and symbols not used for calculations. Numeric data contains numbers that can be manipulated mathematically by adding, averaging, multiplying and so forth. The are several numeric data types, including real, integer, and date. The real data type is used for fields that contain numbers with decimal places- prices, percentages, and so on. The integer data type is used for fields that contain whole numbers-quantities, repetitions, rankings, and so on. The date data type is used to store dates in a format that allows them to be manipulated, such as you want to calculate the numbers of days between two dates.

The text data type is typically assigned to fixed-length fields that hold character data- people’s names, albums titles, and so on. Text fields sometimes hold data that looks like numbers, but doesn’t need to be mathematically manipulated. Telephone numbers and ZIP codes are examples of data that looks numeric, but should be stored in text fields. A memo data type usually provides a variable-length field into which users can enter comments. The logical data type (sometimes called a Boolean or yes/no data type) is used for true/false or yes/no data using minimal storage space. Some file and database management systems also include additional data types, such as BLOBs and hyperlinks. A BLOB (binary large object) is a collection of binary data stored in a single field of a database. BLOBs can be just about any kind of data you would store as a file, such as an MP3 music track. The hyperlink data type stores URLs used to link directly from a database to a Web page.

The information produced by reports and processing routines is only as accurate as the information in the database. Unfortunately, data entry errors can compromis e the accuracy and validity of a database. When designing a database, it is important to think ahead and envision potential data entry errors. Preventing every typographical error is not possible. However, it is possible to catch some of these errors by using field validation rules, list boxes, or lookups. A process called normalization helps to create a database structure that can save storage space and increase processing efficiency. The goal of normalization is to minimize data redundancy – the amount of data that is repeated or duplicated in a database.

Records in a database can be organized in different way depending how people want to use them. No single way of organizing the data accommodates everyone need’s, but tables can be sorted or indexed in multiple ways. A table’s sort order is the order in which records are stored on disk. Sorted tables typically produce faster queries and updates. In a sorted table, new records are inserted to maintain the order. Most DBMSs use a sort key to determine the order in which records are stored. A table’s sort key is one or more fields used to specify where new records are inserted in a table. A database index can be used to organize data in alphabetic or numeric order. A database index contains a list of keys, and each key provides a pointer to the record that contains the rest of the fields related to that key.

Designing the database user interface can be a challenging task. If a company’s database includes multiple tables used by many different people, a professional user interface designer usually creates and maintains the user interface. Large databases might even require a group of user interface designers, meanwhile the interfaces for smaller databases, such as those used by small business or individuals, is most likely created by a single one.

A well-defined user interface for a database should be clear, intuitive, and efficient. A designer might consider the following principles:

- Arrange fields in a logical order beginning at the top-left of the screen. The first field should be those used most often or those that come first in the data entry sequence.

- Provide visualclues to the entry areas. An edit box, line, or shaded area can delineate data entry areas.

- Entry areas should appear in a consistent position relative to their labels. By convention, labels are placed left of the entry areas or above them.

- Provide a quick way to move through the fields in order. By convention, the tab key performs this function.

- If all fields do not fit on a single screen, use scrolling or create a second screen.

- Provide buttons or other easy-to-use controls for moving from one record to another.

- Supply on-screen instructions to help ensure that data is entered correctly. Web database can benefit from links to help pages.

After the design for the database structure is completed, it is time to load the database with an initial set of data. Data can be loaded into a database manually by using generic data entry toolssupplied with the DBMS or by using a customized data entry module created by the database designer. Entering data manually can take a long time, however, and mistakes such as misspelling are common. If the data exists electronically in another type of database or in flat files, it is usually possible to transfer the data using a custom-written conversion routine or import and export routines. A conversion routine converts the data from its current format into a format that can be automatically incorporate into the new database. It takes some time and requires knowledge about database formats to write conversion routines, but for large databases, it’s much quicker to convert data than to re-enter it manually. Converting data also results in fewer errors.

Some DBMSs provide built-in import and export routines that automatically convert data from one file format to another. An import routine brings data into a database. For example, if data was previously stored as a spread-sheet file, an import routine in Microsoft Access can be used to transfer data from the spreadsheet to an Access database. In contrast, an export routine copies data out of a software package, such as spreadsheet software, and into the database. Typically, you would use either an import routine or an export routine to move data from one location to another, but not both.

 

Comprehension check. Choose the ending for each sentence from the two versions given.

1. The key to an effective database is

a) its initial design.

b) to determine what data must be collected and stored.

2. The term database structurerefers to

a) the arrangement of fields, tables, and relationships in a database.

b) the concept of breaking data into fields.

3. From a technical perspective, data typespecifies

a) the way data can be manipulated.

b) the way data is represented on the disk and in RAM.

4. Character data contains

a) letters, numerals and symbols not used for calculations.

b) numbers that can be manipulated mathematically.

5. The goal of normalization

a) to produce timely, meaningful, and accurate information for decision making.

b) is to minimize data redundancy-the amount of data that is repeated or duplicated in a database.

6. After the design for the database structure is completed, it is time

a) to determine the order in which records are stored.

b) to load the database with an initialset of data.

 

Vocabulary practice

1. Which word does not belong to the group?

a) initial, original, primary, subsequent;

b) allow, permit, let, advice (verb + object + to);

c) current, visual, intuitive, efficiently;

d) carry out, execute, fulfill, specify;

e) reduce, decrease, minimize, grow up;

f) tool, device, equipment, gadget.

2. Fill in the blanks choosing from the variants given.

1. In a well-designed database, data can be … manipulated to produce timely, meaningful, and accurate information for decision making.

a) flexibly b) smoothly c) slowly d) hardly

2. The term database structurerefers to the … of fields, tables, and relationships in a database.

a) agreement b) allocation c) arrangement d) appointment

3. A primary keyis a … that contains data unique to record.

a) space b) field c) table d) file

4. When designing a database, you should … and envision potential data entry errors.

a) think ahead b) think about c) think over d) think out

5. Entering data … can take a long time, however, and mistakes such as misspelling are common.

a) electronically b) automatically c) in written form d) manually

6. A conversion routine … the data from its current format into a format that can be automatically incorporate into the new database.

a) provides b) transfers c) converts d) supplies

 

3. Transform the given sentences using the word in brackets without any change in meaning. You may omit, change or add words as required.

1. The goal of database design is to store information so that it easy to access and maintain (aim).

2. The treatment of first and last name illustrates the concept of breaking data into fields (shows).

3. BLOBs can be just about any kind of data you would typically store as a file, such as an MP3 music track (usually).

4. The information produced by reports and processing routines is only as accurate as the information in the database (exact).

5. No single way of organizing the data accommodates everyone need’s, but tables can be sorted or indexed in multiple ways (satisfies).

6. Typically, you would use either an import routine or an export routine to move data from one location to another, but not both. (place).

 

4. Fill in the gaps in the text.

 

The first step in designing relational data base is to define its fields by specifying a ___and data type. Integer, date and ___ data types are used for fields that might be mathematically manipulated. The ___ data type is used for fixed-length fields containing text that is not intended to be mathematically manipulated. The ___ data type is a variable-length field for entering text. The ___ data type is used to store true/false or yes/no data. The ___ data type is used to store binary data, such as MP3 files or graphics. When designing fields, a database designer can also include field formats, field ___ rules, and lookup routines to reduce data entry errors.

 

Speaking. Discuss the following questions.

 

1. What is the goal of a well-designed database?

2. What does the term database structure refer to?

3. Speak on the first step in structuring a relational database? What is the next step?

4. Why are last names stored in a different field than first names?

5. What does make each record unique?

6. How does a database designer know what data types to use?

7. Can a database designer prevent people from entering inaccurate data?

8. What is normalization?

9. What are the principles that a designer might consider to improve this database?

10. How is data loaded into database tables?

Text D

Pre-reading task. Match the meaning of the following English words with their Russian definitions.

1. SQL query a) запись

2. Database client software b) полное обновление

3. Relation database c) язык запросов

4. Record d) реляционная база данных

5. Global update e) ключевое слово

6. Parameter f) программное обеспечение клиента базы данных

7. Keyword g) SQL-запрос

8. Query language h) слово-команда

9. Command word i) объединение таблиц

10. Joining tables j) параметр

Reading. Read the text and try to guess the meaning of the words in bold. Check your variants in the dictionary.

SQL

Addingrecords, finding information and making updates are all important aspects of database use. Most people who access a database on a “casual” basis interact with very simple user interfaces. These user interfaces shield users from the intricacies of sophisticated query languages. Nevertheless, a little background in query languages can help you understand the power and capabilities of databases.

Query languages like SQL ( Structured Query Language ) typically work behind the scenes as an intermediary between the database client software provided to users and the database itself. Database client software provides an easy-to-use interface for entering search specifications, new records, data updates, and so on. The client software collects your input, and then converts it into an SQL query, which can operate directly on the database to carry out your instructions.

An SQL query is a sequence of words, much like a sentence. Most implementations of SQL accept either uppercase or lowercase keywords.

The SQL query language provides a collection of special command words called SQL keywords, such as SELECT, FROM, INSERT, and WHERE, which issue instructions to the database. Most SQL queries can be divided into three simple elements that specify an action, the name of database table, and a set of parameters. Let’s look at each of these elements.

An SQL query typically begins with an action keyword, or command, which specifies the operation you want to carry out. For examples, the command word DELETE removes a record from a table, the command word CREATE creates a database or table, the command word INSERT is used to add a record, the command word JOIN uses the data from two tables, SELECT searches for records and UPDATE changes data in the field.

SQL keywords such as USE, FROM, or INTO can be used to construct a clause specifying the table you want to access. The clause consists of a keywords followed by the name of the table. For example, the clause FROM Tracks indicates that you want to use the Tracks table from the Vintage Music Shop’s database.

The term parameter refers to detailed specifications for a command. Keyword such as WHERE usually begin an SQL clause containing the parameters for a command.

One of the most common database operations is to query for a particular record or group of records by using the SELECT command. The phrase, for example, SELECTAlbumTitle, Album Cover specifies that the database should show you only the album title and cover, and until you confirm that is the album you are interested in, it will not show you additional information such as the price or list of tracks.

You can change records in a database only if you have authorization to do so. At Vintage Music Shop’s site, for example, customers do not have authorization to change album prices or alter the name of the songs on an album. The process of purchasing an album, however, does cause an update in the whole database. Your purchase just reduces the number of albums in the shop’s inventory. To accomplish this update, one of the software modules in the shop’s inventory system issues an SQL UPDATE command to reduce the number in the InStock field record. In addition to changing the data in a single record, SQL can perform a global update that changes the date in more than one record at a time. It means that is possible to update a group of records. Suppose you’re Vintage Music Shop’s marketing manager, and you want to put all The Rolling Stones albums on sale by reducing the DiscountPrice to $9.95. You could do it the hard way by searching for an ArtistName field that contains “Rolling Stones”, adjusting the DiscountPrice field for that record, and then looking for the next Rolling Stones album. However, it would be easier to change all records with a single command. The following SQL statement accomplish this global update:

UPDATE Albums

SET DiscountPrice=9.95

WHERE ArtistName=”Rolling Stones”

Let’s see how this command performs a global update. The UPDATE command means you want to change the data in some or all of records. Albums is the name of the record type containing the data you want to change. SET DiscountPrice=9.95 tells the DBMS to change the data in the DiscountePrice field to $9.95. WHERE ArtistName=”Rolling Stones” tells the DBMS to change only those records where the artist name is Rolling Stones. Although the global update function is powerful, it works only for records that have similar characteristics.

Recall that the process of normalization creates tables that can be related by fields that exist in both tables. In SQL terminology, the creating a relationshipbetween tables is referred to as joining tables. To take advantage of the relationship between two tables, you first have to join the tables. Why? Remember that in relational database, the tables are essentiall y independent unless you join them together. The SQL JOIN command allows you to temporarily joinand simultaneously access the data in more than one table.

SQL is a very extensive and powerful language that can be used not only to manipulate data, but also to create databases, tables and reports. Because SQL is one of the most popular database tools, many computer professionals consider SQL fluency as essential career skill.

 

Comprehension check. Match the beginning of the sentences in the first column with the endings in the second.

1. Adding records, finding information, and making updates 2. Query languages like SQL typically work behind the scenes 3. Database client software provides 4. An SQL query is 5. The process of purchasing an album 6. The SQL JOIN command allows you

a) as an intermediary between database client software provided to users and the database itself. b) are all important aspects of database use. c) a sequence of words, much like a sentence. d) only if you have authorization to do so. e) an easy-to-use interface for entering search specifications, new records, data updates and so on. f) does cause an update in the whole database. Your purchase just reduce the numbers of albums in the shop’s inventory.

 

Vocabulary practice

1. Put the letters in the words in brackets into the correct order.

1. A little … in query languages can help you understand the power and capabilities of databases (roducknabg).

2. An SQL query typically begins with an action …, or command, which specifies the operation you want to carry out (weykdor).

3. The clause consists of a keywords followed by the name of the … (ablet).

4. Your … just reduces the numbers of albums in the shop’s inventory (sacherup).

5. The term … refers to detailed specifications for a command (earpmaret).

6. Although the global update function is powerful, it works only for … that have similar characteristics (coerdrs).

 

2. Fill in the blanks choosing from the variants given.

1. Most people who access a database on a “casual” basis … with very simple user interface.

a ) manipulate b) work c) operate d) interact

2. A little … in query languages can help you understand the capabilities of databases.

a) certainty b) background c) career skills d) experience

3. The SQL query language provides a collection of special command … called SQL keywords, such as SELECT, FROM, INSERT, and WHERE, which issue instructions of the database.

a) words b) passwords c) names d) numbers

4. Most SQL queries can be divided into three simple elements that … an action, the name of database table, and a set of parameters.

a) execute b) indicate c) construct d) specify

5. Customers do not have … to change album prices or alter the name of the songs on an album.

a) authorization b) rights c) permission d) possibilities

6. SQL is a very extensive and powerful language that can be used not only to … data, but also to create databases, tables and reports.

a) enter b) manipulate c) to make updates d) input

 

3. Match the beginnings and the endings of the steps given and put them into correct order.

1 SET DiscountPrice=9.95 tells 2. WHERE ArtistName=”Rolling Stones” tells 3. Albums is 4. The UPDATE command means 5. It means that 6. SQL can perform a global update

a) the name of the record type containing the data you want to change. b) to change the data in the DiscountePrice field to $9.95. c) to change only those records where the artist name is Rolling Stones. d) you want to change the data in some or all of records. e) that changes the date in more than one record at time. f) is possible to update a group of records.

4. Fill in the gaps in the text.

SQL is a database query language that typically works behind the scenes as an intermediary between the database ___ software provided to users and the database itself. Although the specifications for searchers and other database tasks are collected by easy-to use graphical user interfaces, those specifications are converted into SQL ___ which can communicate directly with the database. An SQL query contains SQL ___ such as SELECT, FROM, INSERT, JOIN and WHERE, plus ___ that specify the details of the command. Records can be removed from a database using the SQL ___ command. Record can be added to a table using the SQL ___ command. To search for data, you can use the SQL ___ command. To change or replace the data in a field requires the SQL ___ command.

 

Speaking. Discuss the following questions.

 

1. What are the most important aspects of database use?

2. Why is so important to have a little background in query languages?

3. What does the abbreviation SQL stand for?

4. How does a query language like SQL work?

5. What does a simple SQL query look like?

6. How does SQL specify the action that someone wants carried out in the data base? Speak on the most commonly used SQL command words.

7. How does SQL specify which table to use?

8. How do SQL queries carry out searches?

9. Is it possible to change the contents of records or to update a group of records? What does the process of purchasing cause?

10. How is the date retrieved from more than one table at a time? What command does allow you to access the data in more than one table?

 

Critical thinking. Read the article and express your opinion on the problem.

Privacy

You might be astonished by the amount of information stored about you in computer database. You bank has information on your financial status, credit history, and the people, organizations, and businesses to which you write checks. School records indicate something about your ability to learn and the subjects that interest you. Medical records indicate the state of your health. Credit card companies track the places you shop and what you purchase in person, by main, or on the Web. Your phone company stored your phone number, your address, and a list of the phone numbers you dial. The driver’s license bureau has your physical description. Your internet cookies track many of the Web sites you frequent. By compiling this data-a process sometimes referred to as “profiling’-an interested person or company could guess some very privet things about you, such as your political views or even your sexual orientation.

When records were stored on index cards and in file folders, locating and distributing data constituted a laborious process that required hand transcriptions or photocopies of piles of papers. Today, this data exists in electronic format and easy to access, copy, sell, shop, consolidate, and alter.

Privacy advocates point out the potential for misusing data that has been collected and stored in computer database. In response to terrorist threats, the Pentagon is working on several controversial projects designed to mine data from database that store information about passports, visas, work permits, car rentals, air-line reservations, arrests, bank accounts, school grades, medical history, and fingerprints. Government data miners believe that data mining could uncover terrorists. P