Vocabulary practice. 1. Which word does not belong to the group?

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, SELECTsearches 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 essentially 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.