Databases and spreadsheets

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Words to know

Unit 17

1 database, n	база данных, БД
2 field, n	поле; пространство; область; зона
3 record, n	запись
4 search, v,n	поиск; искать, перебирать
5 condition, n	условие, состояние
6 selection, n	селекция; выбор(ка), выбор, вариант выбора, выбранный элемент
7 rule, n	линейка, линия (в НИС), правило (например, в нечёткой логике)
8 cell, n	ячейка, клетка
9 row, n	ряд; строка
10 column, n	колонка, столбец; графа
11 formula, n	формула; аналитическое выражение
12 a blank record, n	пустая запись
13 a query language, n	язык запросов
14 SQL(Structured Query Language), n	язык структурированных запросов, язык SQL
15 logical operator, n	логический оператор
16 search condition, n	условие поиска
17 wildcard,n	подстановочный символ
18 wildcard symbol, n	подстановочный символ, шаблон подстановки
19 cell reference, n	ссылка на ячейку, адрес ячейки
20 spreadsheet, n	крупноформатная (электронная) таблица
21 addition, n	сложение, суммирование
22 subtraction, n	вычитание
23 multiplication, n	умножение; перемножение
24 division, n	деление
25 percentage, n	процент, процентное отношение
26 spreadsheet program, n	программа обработки крупноформатных таблиц
27 sum function, n	сумма-функция
28 rectangular box, n	прямоугольник
29 grid, n	сетка
30 array, n	массив

A database is used to store information so that it can be searched and sorted in various ways. Each item of information is sorted in various ways. Each item of information is stored in a field. A collection of related fields forms a record. Simple searches can often be created by allowing the user to type the required field information into a blank record, and pressing a search button. More advanced database programs usually use a query language known as SQL (Structural Query Language). This allows users to type statements using logical operators to specify the search conditions.

Logical operator	Meaning
A. AND. B	both condition A and condition B are true
A. OR. B	either condition A or condition B or both are true
. NOT. A	condition A is not true

If you only known part of the field you are searching for, you can use special symbols, called wildcards, to represent combinations of characters. Although the actual wildcard symbols used can vary, most programs use a standardized set of wildcard symbols.

A spreadsheet program is used for calculating formulae. It is made up of a grid or array of rectangular boxer called cells, as shown below.

	A	B	C	D

The columns are labelled A, B, C … and the rows of cells are numbered 1, 2, 3 … To refer to a particular cell, you use the column label followed by the row number. For example, the cell in the top left corner of the spreadsheet is A1, the one to the right of it is B1, and the one below it is A2. The cells can contain text, numbers, or formulae. The formulae are written using the cell references, e.g. to add the first three cells in the A column, you would use the formula A1+A2+A3, or the sum function Sum (A1:A3), i.e. the sum of cells A1 to A3. When a formula is assigned to a cell, the result of the formula is displayed in the cell rather than the formula itself. By varying spreadsheet values and formulae, different possible outcomes can be analysed.

Other common mathematical symbols used in formulae are shown in the table below.

Symbol Name Function
+	plus	addition
-	minus	subtraction
*	multiply by (or times)	multiplication
/	divided by	division
%	per cent	percentage

3 Answer the following questions:

1 What is a database used for?

2 Where is each item of information stored in?

3 What is a spreadsheet program used for?

4 What common mathematical symbols used in formulae do you know?

Дата добавления: 2014-12-23