What is a database called? Databases and information systems

Communication of information systems and databases

Definition 1

Logically related data formalized in some way in a single way, so that they can be processed by a computer are called database

Databases are created, stored and processed in special programs called database management systems (DBMS). But for efficient work With data, a database managed by a DBMS is not enough. Typically, data is needed for use in some type of activity. For example, a patient’s personal data is needed in the process of registering his medical card in a clinic, data on goods sold is needed for accounting at enterprises retail, data on the results of the session are needed in the process of awarding scholarships to students, etc. All these types of activities are specific, they have their own rules and their own terminology. Therefore for them information support We need special programs where familiar terminology is used and all the rules are taken into account. Such programs are called information systems (IS).

Definition 3

The part of the real world that is to be studied in order to develop an information system is called subject area.

The subject area is described by many objects, many processes that use these objects, and many users united by a single view of the entire system.

Definition 4

A set of rules and principles for the behavior of objects subject area called business logic IS.

Example 1

Let’s say that each store customer, with three purchases made within a month, receives a 2% discount. This requirement is part of the business logic. When developing a store's IP, it should be taken into account in the form of a separate procedure that will automatically find such customers and assign them a discount.

When designing an IS, it is necessary to determine what data and for what purposes will be stored in the system, as well as how their storage and processing will be organized. Thus, the database and DBMS are integral part(IS). In addition to databases, the information system includes a system of interconnected applications that implement business logic.

Classification of information systems

According to the areas of application, IP is divided into

• Information retrieval (IRS);
• Data processing systems (DPS).

The main task of the information retrieval system, as a rule, is to search and retrieve part of the stored data that meets some selection criterion. A classic example of an information retrieval system is Internet search servers. User requests to ODS, as a rule, end with adding new data or editing existing ones. The stored data is processed programmatically and outputs as reports and documents. A classic example of SOD is the information system of banks and supermarkets.

Depending on the type information resources, with which the IS works, they are divided into two classes:

• Documentary;
• Factual.

Documentary information systems directly store documents containing information. Articles can be used as documents, geographic Maps, photographs, audio recordings, etc. In this case, the database stores only links to documents and those details that can be formalized. Documentary IP is most often information retrieval.

Factual information systems store formalized data on the conduct of any operations. For example, data on the receipt of goods from suppliers, data on the transfer of materials from the warehouse to the workshop, etc. Factual information systems contain data about objects of the subject area in their relationship with each other.

In today's economy, IP is not developed once and for all. Most information systems are repeatedly modified during their service life to meet changing conditions of the subject area. It is often necessary to organize data exchange between different ISs that are built on various platforms by different development teams using different DBMSs. To do this, the IS must provide functions for importing and exporting data based on standard data exchange formats.

Many, having begun to explore the world Web, still have no idea what it is Database. But almost all Internet users have already used it at least once - saving user data on the site, processing search queries and much more. Most of the data is stored in the Database, and in order to display certain information, it processes a request for the database. So what is it?

Database- a complex of data (information) that is structured and interconnected.

An example is library. Yes, yes, there are not just books on the shelves, but they exist different kinds Catalogs through which a librarian can find a specific book (by alphabet - author or title, by shelf, by subject). Thus, having accepted a request for a book, it was then possible to find it based on a certain criterion. We can say that data was stored and processed in the library. But wouldn’t the data be of such interest if they couldn’t also be managed! So we come to the next term.

Database Management System- is a collection of linguistic and software, the main functions of which include the ability to create data, process it, read it, delete it, and implement secure database control.

In general, a DBMS is a system that allows you to create databases and manipulate information from them. And it provides this access to DBMS data through a special language - SQL.

SQL- a universal structured query language, the main tasks of which include reading, writing and deleting information in the Database.

From the history of SQL

In the early 1970s, in one of the company's research laboratories IBM an experimental relational DBMS IBM System R was developed, for which a special language was then created SEQUEL, which made it relatively easy to manage data in this DBMS. The abbreviation SEQUEL stood for Structured English QUEry Language- “structured English language requests." SEQUEL was later renamed to SQL.

The date of creation is considered to be 1974.
The authors are considered Donald Chamberlin, Raymond Boyce.
The first standard was adopted in 1986.

What is MySQL

MySQL- a database management system that can work with PHP, Java, Perl, C, C++ and other programming languages. One of the most widespread DBMS in the world. Included in popular portable server builds Denwer And XAMPP, as well as to servers WAMP, LAMP, AppServ. Written in C, C++. developer - Oracle(since 2010).

Examples of SQL queries

Will display a list of ALL databases.

SHOW databases;
Will list ALL tables in the base_name Database.

SHOW tables in base_name;
Selects ALL data in the tbl_name table.

SELECT * FROM tbl_name;
More in detail requests can be found in the article

Lesson " Basic concepts of database "

Any of us, starting from early childhood, have repeatedly encountered “databases”. These are all kinds of directories (for example, telephone directories), encyclopedias, etc. A notebook is also a “database” that each of us has.

Databases are information models containing data about objects and their properties. Databases store information about groups of objects with the same set of properties.

For example, the “Address Book” database stores information about people, each of whom has a last name, first name, telephone number, and so on. A library catalog stores information about books, each of which has a title, author, year of publication, and so on.

Information in databases is stored in an orderly manner. So, in notebook all records are ordered alphabetically, and in the library catalog - either alphabetically - alphabetical catalogue) or by area of ​​knowledge (subject catalogue).

There are several different structures information models and correspondingly various types databases: tabular, network, hierarchical (see models).

Hierarchical databases

Hierarchical databases can be graphically represented as an inverted tree consisting of objects at different levels. Top level (tree root ) occupies one object, the second - objects of the second level, and so on.

There are connections between objects; each object can include several objects more than low level. Such objects are in relation ancestor (object closer to the root) to descendant (a lower-level object), while an ancestor object may have no children or several of them, while a descendant object necessarily has only one ancestor. Objects that have a common ancestor are called twins .

For example: a hierarchical database is Folder directory Windowswhich you can work with by launching Explorer. The top level is occupied by the folder Desktop. On the second level there are folders My computer, My documents, network And Basket, which are children of the folder Desktop, and are twins to each other. In turn, the folder My computer is an ancestor in relation to third-level folders - disk folders (Disk 3.5(A:), (C:), ( D:), (E:), (F:))and system folders (Printers, Control Panel and etc.)

Network Databases

A network database is a generalization of a hierarchical database by allowing objects to have more than one ancestor. In general, on the connection between objects in network models no restrictions are imposed.

A network database is actually World Pow mu n aglobal computer network Internet. Hyperlinks link hundreds of millions of documents into a single distributed network database data.

Tabular Databases

A tabular database contains a list of objects of the same type, that is, objects that have the same set of properties. It is convenient to represent such a database in the form of a two-dimensional table: in each of its rows the values ​​of the properties of one of the objects are sequentially placed; Each property value is in its own column, headed by the property name.

Consider, for example, a database:Phonebook

№	Surname	Address	Telephone
	Ivanov V.V.	Serova, 5 12	4325345
	Petrov I.I.	Sedova, 3-21	3454365
	Sidorov S.S.	Mira, 33-17	3454354

The columns of such a table are called fields; Each field is characterized by its name (the name of the corresponding property) and the data type representing the values ​​of this property.

Table rows are records about an object; these records are divided into fields by table columns, so each record is a set of values ​​contained in the fields.

Each table must contain at least, one key field whose contents are unique for each record in this table. A key field allows you to uniquely identify each record in a table.

The field most often used as a key mole is containing data type counter . However, sometimes it is more convenient to use others as the key field of the table fields: product code, inventory number, etc.

Phonebook

Field names	№	Surname	Address	Telephone
Record		Ivanov V.V.	Serova, 5 12	4325345
Record		Petrov I.I.	Sedova, 3-21	3454365
Record		Sidorov S.S.	Mira, 33-17	3454354
	Key field	Field	Field	Field

The field type is determined the type of data it containslive The fields may contain the following basic data: types:

counter - integers that are set automaticallyski when entering records. These numbers cannot be changed user;

text - texts containing up to 255 characters;

numerical- numbers;

date Time - date or time;

monetary - numbers in monetary format;

logical - values True(Yes or Lie(No);

OLE object field - image or drawing

Each field type has its own set of properties. Most in important properties of fields are:

field size - defines the maximum text lengthnumeric or numeric field;

field format - sets the data format;

Obligatory field - indicates that this field must be filled out

Database management system Access (DBMS)

Purpose and main functions

The development of information technology has led to the creation computer databases data. Database creation and operationssearch and data sorting is performed special programs - database management systems (DBMS).

Thus, it is necessary to distinguish between databases themselves (DBs), which are ordered sets of data, and database management systems - programs that manage the storage and processing of data.

The database management system is the application Access, included with Microsoft Office.

Program interface Access

In Access the standard one for the environment is used Windows & Office multi-window interface, but unlike other applications, not multi-document. At one time there may be only one database is open , containing mandatory database window And windows for working with database objects. At each moment of time, one of the windows is active and the cursor marks the active object in it. Database Window - one of the main interface elements Access . All database objects are systematized here: tables, queries, forms, reports, macros and modules. You can move between records using using the mouse, cursor keys, or scroll bars. To quickly move between records in the database, you can use the navigation buttons on the panel Record, which is located at the bottom of the table window.

Objects in the Access DBMS:

· Table.In databases, all information is stored in two-dimensional tables. This base database object, all other objects are created based on existing tables (derivatives objects).

· Requests.Queries are designed to select data based on specified conditions. Using a database query, you can select information that meets certain conditions.

· Forms.Forms allow you to display data contained in tables or queries in a more readable form. Using forms, you can add new data to tables, as well as edit or delete existing ones. The form may contain pictures, graphs, and other embedded objects.

· Reports.Reports are designed to print the data contained in tables and queries in a beautifully formatted manner.

· Macros.Macros are used to automate repetitive operations. Recording a macro is done in the same way as in other applications, for example as in the application Word.

· ModulesModules also serve to automate work with the database. Modules are also called event processing procedures and are written on language VBA.

Federal agency of Education

State Educational Institution

Secondary Vocational Training

"Tula Economic College"

In the discipline "Informatics"

On the topic: “Database. The concept of a database. Types of databases. Objects for working with databases. Data types in Access databases and tables. Basic elements and concepts of databases"

Prepared by a 2nd year student

group 216-BP

Khramova Anna

Checked by the teacher:

Vasilyeva I.V.

Shchekino, 2007

WITH ABOUT D E R AND A N AND E:

1. Introduction……………………………………………………...…………….……2

2. The concept of a database……………………………………………..3

3. Types of database………………………………………….………4-5

4. Objects for working with databases…………………………...6-7

5. Types of data in databases………………………………………………….8

6. Data types in Access tables……………………………………9

7. Basic elements and concepts of databases…………………..10-15

8. Test…………………………………………………………….…16-17

9. Answers to the test……………………………………………………………...…….…18

10. Questions for self-test…………………………….........19

11. List of references……………………………….20

12. Presentation……………………………………………………21-33

13. Review……………………………………………..…………..34

INTRODUCTION:

We met Excel work and we know that this application was created specifically to solve problems of processing tabular data.

There are systems (applications) for solving other classes of problems. In particular, programs (applications, systems) now play a very important role, the chain of which is storing data and issuing data at the user’s request.

The use of computers specifically for solving this class of problems is becoming an increasingly widespread phenomenon.

We can safely say that such problems and the need to solve them exist in any company, in any enterprise.

The main concept for this range of tasks is a database. This is the name of a file or group of files of a standard structure used to store data.

To develop programs and program systems that work with databases, we use special means– database management systems (DBMS).

A DBMS, as a rule, includes a special programming language and all other tools necessary for the development of these programs.

Currently, the most well-known DBMSs are FOXPRO and ACCESS. The latter is part of the MS Office 97 professional package.

This modern systems with great capabilities, designed for the development of complex software systems, and getting to know them is extremely useful for a computer user, but it is difficult to implement within the framework of this manual.

Database concept

Database (DB) is a collection of data arrays and files, organized according to certain rules that provide standard principles for describing, storing and processing data, regardless of their type.

Database (DB)– a set of organized information related to a specific subject area, intended for long-term storage in external memory computer and constant use.

Types of database:

1. Factual – contains brief information about objects of some system in a strictly fixed format;

2.Documentary – contains documents of the different types: text, graphic, sound, multimedia;

3. Distributed - a database, different parts of which are stored on various computers, united in a network;

4.Centralized – database stored on one computer;

5. Relational - a database with a tabular organization of data.

One of the main properties of a database is the independence of data from the program that uses this data.

Working with a database requires a solution various tasks, the main ones are the following:

Creating a database, writing data to the database, updating data, retrieving data from the database according to user requests.

The tasks on this list are called standard.

The next concept related to the database: a program for working with a database is a program that provides a solution to the required set of problems. Any similar program must be able to solve all standard set of problems.

Database in different systems has a different structure.

PVEM usually uses relational databases - in such databases, a file is structured like a table. In it, the columns are called fields, the rows are called records.

An example of a database would be a train or bus schedule. Here, each line-record reflects the data of strictly one object. The database includes fields: flight number, route, departure time, etc.

A classic example of a database is phonebook. A database query is a statement that specifies what data the user wants to retrieve from the database.

Some queries may represent a serious task that requires writing complex program. For example, a request to the database - the bus schedule: determine the difference in the average departure interval of buses from Rostov to Taganrog and from Rostov to Shakhty.

Objects For work With bases data

To create an application that allows you to view and edit databases, we need three links:

data set

data source

visual elements management

In our case, this triad is implemented in the form:

Table

DataSource

DBGrid

Table connects directly to a table in the database. To do this, you need to set the database alias in the DataBaseName property and the table name in the TableName property, and then activate the connection: Active property = true.

However, since the Table is a non-visual component, although the connection to the database is established, the user is not able to see any data. Therefore, it is necessary to add visual components that display this data. In our case, this is the DBGrid. The grid itself “does not know” what data it needs to display; it needs to be connected to the Table, which is done through the DataSource intermediary component.

Why do we need an intermediary component? Why not connect to Table straight away?

Let's say there are several visual components - a table, input fields, etc. connected to the table. And we need to quickly switch them all to another similar table. With DataSource this is easy to do - you just need to change the DataSet property, but without DataSource you would have to change the pointers for each component.

Database applications - the thread connecting the database and the user:

DB – data set – data source – visual components – user

Data set:

Table (table, navigation access)

Query (query, relational access)

Visual Components:

Grids DBGrid , DBCtrlGrid

Navigator DBNavigator

All sorts of analogues Label , Edit etc.

Substitution Components

Data types in databases

You can define the following field types in Access:

Text – text string; maximum length is set by the “size” parameter, but cannot be more than 255

MEMO field – text up to 65535 characters long

Numeric – in the “Field Size” parameter you can specify a field: byte, integer, real, etc.

Date/time – a field that stores time data.

Monetary – special format for financial needs, essentially numerical

Counter is an auto-incrementing field. When adding a new record, the internal counter of the table is increased by one and written to this field of the new record. Thus, the values ​​of this field are guaranteed to be different for different records. The type is for a key field

Boolean – yes or no, true or false, on or off

An object OLE – documents, pictures, sounds, etc. can be stored in this field. The field is a special case BLOB – fields ( Binary Large Object ), found in various databases

Substitution

Data types in tables Access :

Text

MEMO field

Numerical

Date Time

Monetary

Counter

Logical

An object OLE

Don't forget about indexes.

Link tables.

Integrity communication controls cascading deletion and modification of data.

Exclusive access to the database is needed in order to make fundamental changes to it.

Basic concepts and elements of databases

Databases were needed when there was a need to store large volumes of the same type of information and be able to quickly use it. Databases (in the broad sense of the word) have been used throughout history by priests, officials, merchants, moneylenders, and alchemists.

The main requirement for databases is ease of access to data, the ability to quickly obtain comprehensive information on any issue of interest (it is not only important that the information is contained in the database, it is important how well it is structured and holistic).

As soon as computers appeared and spread, almost immediately they were entrusted with the hard and painstaking work of processing and structuring data, and databases (DBs) in their current understanding appeared.

According to modern requirements for databases, the information contained in them should be:

consistent (there should be no data that contradicts each other);

non-redundant (unnecessary duplication of information in the database should be avoided; redundancy can lead to inconsistency - for example, if some data is changed, but their copy in another part of the database was forgotten to be changed);

holistic (all data must be linked, there should be no references to data that does not exist in the database)

Relational database model was proposed by Edgar Codd in the late 70s. In this model, a database is a set of tables connected to each other by relationships. With sufficient simplicity (and therefore ease of implementation on a computer) this model has the flexibility to describe complexly structured data. In addition, the theoretical basis for this model has been thoroughly developed, which also makes it possible to use the computer more effectively when creating a database and working with it. In terms of communication rules, the relational model implements a one-to-many relationship between tables. This means that one record in the main table corresponds to several records in the subordinate table (and may not correspond to a single record). Other types of relationships: one-to-one, many-to-one, and many-to-many can be reduced to this type"one-to-many". Relational databases data consists of related tables.

Table represents two-dimensional array, in which the data is stored. The columns of the table (within the accepted database designations) are called fields, the rows are called records. The number of table fields is fixed, the number of records is not. In fact, a table is an unfixed array of records with the same field structure in each record. Add to table new entry is not difficult, but adding a new field entails restructuring the entire table and can cause certain difficulties. Numbers, strings, pictures, etc. can be stored in records as field values. Database tables are stored on the hard disk (on local computer or on the database server - depending on the type of database). One table usually corresponds to several files - one main and several auxiliary. The subtleties of table organization depend on the format used (dBase, Paradox, InterBase, Microsoft Access etc.)

Key - a field or combination of table fields whose values ​​uniquely identify a record. The key is called that because, having the values ​​of the key fields, you can unambiguously gain access to the desired record. Thus, keys are extremely useful for linking tables. By writing the key values ​​into the designated fields of the subordinate table and thereby setting a link, we ensure the connection of two records - a record in the main table and a record in the subordinate table. One record of a subordinate table can contain several links to records of the main table. For example, in a school journal there may be a table - a list of duties, where each entry contains the names and surnames (the key of their two fields) of several duty officers. This is how various records of the main table are connected and a rather complex data structure is implemented. In school practice, first and last names are used as key fields, but in the database it is better to allocate special key fields - individual numbers(codes) of records. This is guaranteed to prevent possible problems with namesakes. In a school where such computer clarity is not required, the appearance of two students with the same first and last names in the same class is a very rare event, so such a technical omission can be forgiven. In addition to binding, keys can be used for direct access to records, speeding up work with the table.

Index – a field, just like a key, specially allocated in a table, the data in which, however, can be repeated. They also serve to speed up access and, in addition, for sorting and selection.

Normal forms were invented more to automate the process of creating databases, rather than as a guide for those who create them manually (automatic design of large databases can be done using special systems of programs - tools (CASE). In reality, with manual development, the designer immediately thinks the necessary structure, plans the necessary tables, and does not come from one large table. Normal forms actually formalize intuitive requirements for data organization, helping, first of all, to avoid excessive duplication of data.

First normal form:

information in the fields is indivisible (for example, first and last name should be different fields, not one);

there are no repeating field groups in the table

Second normal form:

the first form is completed;

any non-key field is uniquely identified by the key fields (in effect, a requirement for a key)

Third normal form:

second form completed

non-key fields must be uniquely identified only by key fields (this means that data that does not depend on the key must be placed in a separate table)

The requirement of third normal form has the meaning that a table with fields (Name, Last name, Class, Class teacher) needs to be split into two tables (Name, Last name, Class) And (Class, Homeroom teacher), since the Class field uniquely defines the Class Teacher field (and according to the third form, only keys should uniquely define it).

To gain a deeper understanding of the intricacies of performing operations with records in tables, you need to have an understanding of access methods, transactions and business rules.

Access methods determine how technical operations with records are performed. Access methods are chosen by the programmer during application development. Navigation method based on sequential processing necessary records one by one. It is typically used for small local tables. The relational method is based on processing a set of records at once using SQL queries. It is used for large remote databases.

Transactions determine the reliability of operations in relation to failures. A transaction combines a sequence of operations that either must be completed in full or not at all. If a failure occurs during a transaction, then all the results of all operations included in it are canceled. This ensures that the correctness of the database is not compromised even in the event of technical (rather than software) failures.

Business rules define the rules for conducting operations and provide database management mechanisms. By setting possible restrictions on field values, they also contribute to maintaining the correctness of the database. Despite possible associations with business as commerce, business rules are not directly related to it and are simply rules for managing databases.

Correct database:

- non-redundant;

- consistent;

- holistic

Relational database:

- tables;

- connections between tables using keys

- fields (columns) – fixed;

- records (rows) – easily added and deleted

- uniquely identifies the record

Keys and indexes:

- serve to link tables, direct access, speed up processing, etc.

Normal forms:

- serve to combat data redundancy;

- they demand a lot, but with the best intentions

Access methods:

- navigation;

- relational

Database correctness protection:

- transactions – technical protection

- business rules – logical protection

T E S T

1.Database models:

A) commercial

B) network

IN) object-oriented

G) revolutionary

D) relational

E) integral

2.Types of database:

A) documentary

B) network

IN) graphic

G) relational

3.Which database contains documents of various types?

A) distributed

B) centralized

IN) factual

G) documentary

4.What is an example of a database?

A) pedestrian standing on the side of the road

B) phonebook

IN) schedule of lessons

G) train or bus schedule

5. What is a key?

A) link B) a codeword IN) program G) field or combination of table fields

6. What will be displayed on the screen as a result of executing a program fragment?

M:= ‘biology’;
k:= ‘zoo’ + copy (m, 4, 5);
writeln(k);

A) zoology B) zoo IN) biology G) logy 7.The data set contains: A) navigator DBNavigator B) Table IN) Query 8.Choose the correct statement: monetary field type... A) text string B) text up to 65535 characters long IN) special format for financial needs G) autoincrete field 9.Basic data requirement: A) storage needs large volumes same type of information B) rapid spread information IN) return deletion of information G) ease of access to data and quick retrieval necessary information on an issue of interest 10.What information should be included in the database requirements? A) holistic B) brief IN) consistent G) same type

Answers to the test

Questions For self-tests :

1. What is a database?

2. What is classic example DB?

3. Give some database examples

4. What type of database is usually used in PVEM?

5. What types of databases do you know?

6. What three links do we need to create an application that allows us to view and edit databases?

7. What types of fields can you define in Access?

8. Why do you need exclusive access to the database?

9. What is relational model databases?

10. How many normal forms are there in the database? List them

11. What are transactions?

L AND T E R A T U R A :

1. Computer science. Tutorial for average vocational education(+CD)/Under general ed. I.A. Chernoskutova - St. Petersburg: Peter, 2005. - 272 pp.: ill. pp. 24 - 25

2. Computer science. Textbook for students. ped. universities / A.V. Mogilev; N.I.Pak, E.K. Hoenner; Ed. E.K. Hoenner. – M., 1999. - 816 pp. 185 - 187

3. Computer science. Textbook. – 3rd revision ed./Ed. prof. N.V. Makarova. – M.: Finance and Statistics, 2000. – 768 p.: ill.

R E C E N S

MEANINGS OF THE THEORY. The concept of meaning in the analytical philosophy of language is actually an analogue of what in the philosophy of consciousness is called “mind”, “consciousness” (English), or “Geist” (German), i.e. consciousness, spirit. In the concept of meaning... ... Encyclopedia of Epistemology and Philosophy of Science

Age values ​​that agree well with each other, obtained by the lead isotope method according to decomp. isotope ratios. They indicate good preservation of the abs and the reliability of the found abs. age. Syn.: age values ​​are concordant.… … Geological encyclopedia

Theoretical values ​​of potential derivatives corresponding to an idealized model of the Earth. They are negligibly small or exactly equal to zero, so the measured values ​​of the second derivatives of the gravitational potential can practically be considered... ... Geological encyclopedia

- (g 0) theoretical values ​​of the force of gravity acting on a unit mass correspond to a model of the Earth in which the density inside the spherical shells is constant and changes only with depth. The structure of their analytical expression... ... Geological encyclopedia

Syn. term age meanings are inconsistent or divergent. Geological Dictionary: in 2 volumes. M.: Nedra. Edited by K. N. Paffengoltz et al. 1978 ... Geological encyclopedia

Obtained by the lead isotope method using four different solutions. Isotopic ratios: , and greatly diverging from each other in magnitude. They indicate poor preservation of the baby and a violation of the radioactive balance in it between maternal and... ... Geological encyclopedia

Syn. term age meanings are consistent. Geological Dictionary: in 2 volumes. M.: Nedra. Edited by K. N. Paffengoltz et al. 1978 ... Geological encyclopedia

values ​​of abnormal operating mode parameters- abnormal operating mode data [Intent] Parallel texts EN RU The P63x generates a large number of signals, processes binary input signals, and acquires measured data during fault free operation of the protected object as well as fault… …

Terms and concepts of general morphology: Dictionary-reference book

meanings of verb orientation- Values ​​of spatial modification of actions and derivatives from them... Dictionary of linguistic terms T.V. Foal

values ​​(voltage) between line and ground- - [Ya.N.Luginsky, M.S.Fezi Zhilinskaya, Yu.S.Kabirov. English-Russian dictionary of electrical engineering and power engineering, Moscow, 1999] Topics of electrical engineering, basic concepts EN line to ground values ​​... Technical Translator's Guide

Books

• , A. Potebnya. Reproduced in the original author's spelling of the 1888 edition (Voronezh publishing house). IN…
• Plural meanings in Russian, A. Potebnya. This book will be produced in accordance with your order using Print-on-Demand technology. Reproduced in the original author's spelling of the 1888 edition (Voronezh publishing house...