Presentation "Databases" (grade 11) in computer science - project, report. Hierarchical databases


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Slide 2

Databases are used to store and search large amounts of information. Examples of databases: notebook, dictionaries, reference books, encyclopedias. Database – structural information model DATABASE (DB) – a set of stored interconnected data, organized according to certain rules Kolesova Zh. V.

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Based on the nature of the information stored, databases are divided into: Factual databases contain brief information about the objects being described, presented in a strictly defined format. For example, a library database stores bibliographic information about each book: year of publication, author, title, etc. Documentary databases contain documents (information) of various types: text, graphic, audio, multimedia (for example , various reference books, dictionaries) Kolesova Zh.V.

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EXAMPLES OF DATABASES: DB of the library's book collection; DB of the institution's personnel. DB of legislative acts in the field of criminal law; Database of modern rock music. factual documentary The database itself includes only information (DB - “information warehouse”) Kolesova Zh.V.

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According to the storage method, databases are divided into Centralized database - the database is stored on one computer Distributed database - different parts of one database are stored on many computers interconnected by a network Example: information on the Internet, united by the WWW web Kolesova Zh. V.

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According to the structure of organization, databases are divided into RELATIONAL NON-RELATIONAL HIERARCHICAL NETWORK A relational database (from the English word relation) is a database containing information organized in the form of rectangular tables interconnected. Such a table is called a relation. A hierarchical table is called a database in which the information is ordered as follows: one element of the record is considered the main one, the rest are considered subordinates. A hierarchical database is formed by a file system on disk, a family tree. A network database is called a database in which horizontal connections are added to the vertical hierarchical connections. Kolesova Zh. V.

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DB STRUCTURE Each table must have its own name. A record is a table row. A field is a table column. The table is an information model of a real system. A record contains information about one specific object. The field contains certain characteristics of objects. The main element of the database is the entry of Zh. V. Kolesov.

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Table name field record The main key is a field or a set of fields that uniquely identifies a record in the table Zh. V. Kolesov.

Database

scheme

filling

  • Defines what parameters and relationships objects have
  • Values ​​of parameters of objects currently recorded in the database

Statements about the full name, date of birth, address, telephone number of students at secondary school No. 20

Student Ivanov P.K., October 12, 1998, lives at mn2, no. 7, apt. 11, telephone 2 – 45 - 65


Database

factual

Library database

documentary

Law database

Contemporary music database


  • Database management system (DBMS) is a control program designed to create, enter, store and process databases.

Applied

program

Human

DBMS examples:

  • Microsoft Office Access
  • Visual FoxPro
  • Borland dBase.

DBMS

Database


Main features of the DBMS

  • high reliability of information storage;
  • updating, replenishment and expansion of databases
  • output of complete and reliable information to requests;
  • ensuring information security.

Applied

program

Human

DBMS

Database


Data integrity in the database

  • Data integrity in the database
  • Integrity Constraint


Roles of users who work with the database

  • Developer
  • User
  • Administrator
  • Developer(creates a database schema)
  • User(works with data)
  • Administrator(defines integrity constraints and sets access rights)

Base models

data

Hierarchical databases

Network Databases

Relational Databases

Totality

objects,

at various levels,

and one of them

is

the main thing, the rest -

subordinates

Totality

objects, with

many

connections between

information,

organized

rectangular


  • Information in databases can be organized in different ways.
  • Most often used tabular method.
  • Databases with a tabular form of organization are called relational databases.

Concept of essence

Class

student

Textbook

computer science

Training score

achievements

teacher

Domain model Computer science at school


  • The essence of the subject area– this is a set of objects that have the same set of parameters.
  • Entity-relationship model is intended for graphical representation of entities of a certain subject area, their parameters and connections between them.
  • Essence Teacher: passport, full name, gender, specialty. (attributes)

  • One to one 1 – 1
  • One to many 1 – ∞
  • Many to many ∞ – ∞
  • The teacher is the class teacher
  • Students study in grade 11 - A
  • Teacher teaches 11th grade

  • The essence of the subject area
  • Communication type

leads

Class

teacher

studies

Class

student

teaches

Class

Teacher



Basic Database Concepts

  • records(table rows)
  • fields(table columns)
  • key field(a field or several fields that uniquely identify a record)

Sigov A.K.

Fuchika 1 0, apt. 3 0

Pershin I.A.

434 1234

Rudenko T.V.

Umanskaya 2, apt. 1 6

1234 375

Sevastopolskaya 1, apt. 8

24 1234 0


Municipal autonomous educational institution

"Miass Secondary School No. 16"

Presentation

in computer science for 9th grade

on the topic of:

Computer science teacher, 1st category

Shavaleeva Svetlana Alekseevna

Miass


DATABASE.


INFORMATION SYSTEM is a collection of a database and the entire complex of hardware and software for its storage, modification and retrieval of information for interaction with the user

DATABASE MANAGEMENT SYSTEM (DBMS) Software designed to work with databases

DATABASE (DB)


DATABASES AND INFORMATION SYSTEMS

DATABASE (DB)

An organized collection of data intended for long-term storage in the external memory of a computer and permanent use

FACTUAL

Brief information about objects in a strictly defined format

DOCUMENTARY

DISTRIBUTED DBs

Documents in various formats

Storing different parts of one database on multiple computers interconnected by a network.

  • text information
  • graphic objects
  • audio information
  • multimedia objects
  • . . . . . . . . . . . . . . . . . .
  • library catalog
  • personnel database
  • reference file
  • . . . . . . . . . . . . . . . .


Hierarchical model

In the hierarchical model, the information structure has the form of a tree. At the topmost (first) level there is only one vertex, which is called the root. This vertex has connections with vertices of the second level, vertices of the second level have connections only with vertices of the third level, etc.


  • In the network model, the main structure information representation has the form of a network, in which each vertex can have a connection with any other.

  • In the relational model information is presented in table form. The rows of the table are records, and the columns are the same fields.

DATABASE MANAGEMENT SYSTEMS

  • DBMS - an application program designed to work with a database.

DBMS are software tools that provide access to information stored in a database, its maintenance and processing.

  • DBMS examples:
  • KBASE, FOXPRO, VISTA, RBDMSX, ACCESS.
  • KBASE
  • FOXPRO,
  • VISTA,
  • RBDMSX
  • ACCESS.

DATA TYPES

1) Text - The meaning of a text data is represented by a set of alphanumeric characters. The length of text data does not exceed 255 characters. Default, Microsoft Access sets the length to 50 characters. Setting the length of a text field means that if you try to enter longer text in that field, extra characters will be ignored. If a text field contains numeric data, then this data is perceived as text and cannot participate in mathematical operations.

Text data type

Text data type


DATA TYPES

2) Counter - used for automatic numbering of records.

Counter data type


DATA TYPES

3) Numerical - used for data (integer and fractional) involved in calculations.

Numeric data can be in any of the following formats:

Meaning

Description

Byte

Numbers from 0 to 255 (without fractional part)

Whole

Fraction

Long integer

Numbers from -32768 to 32767 (without fractional part)

Absent

Size

1 byte

(Default value). Numbers from -2147483648 to 2147483647

(without fractional part)

Absent

Floating point (4 bytes)

Floating point (8 bytes)

Numbers from

-3.402823* to 3.402823*

Absent

2 bytes

4 bytes

Numbers from

-1.79769313486232* to 1.79769313486232*

Replication code

4 bytes

Globally unique identifier (GUID)

8 bytes

Undefined

16 bytes


DATA TYPES

4) Date/Time- used to store time or date. It is possible to make calculations with data (calculate the time interval between individual dates).

Date data type


DATA TYPES

5) Monetary - almost the same as the numeric type, but with a fixed number of decimal places and a currency sign.


DATA TYPES

6) Boolean fields - are used to store data that can take one of two possible values: True / Lie , Yes / No or On off. In this case, the values True , Yes And On True, and the values Lie , No And Off equivalent to boolean value False .


DATA TYPES

7) OLE object fields - allows you to store images and other binary data in tables (for example, a spreadsheet Microsoft Excel, document Microsoft Word, drawing, sound recording).


DATA TYPES


DATA TYPES

9) Field MEMO - Free-length text fields can contain the same data types as simple text fields. The difference between these fields is that the field size MEMO is not limited to 255 characters, but can contain up to 65535 characters.


DATA TYPES

10) Lookup wizard data type - is designed to create a field that offers a selection of values ​​from a drop-down list containing a set of constant values ​​or values ​​from another table.


TYPES OF FIELDS IN RELATIONAL DATABASES

Field type defines the set of values ​​that a given field can take on in different records

numerical

symbolic

date Time

logical

These fields are designed to store calendar dates and time of day data

Date: "day/month/year"

Time watch : minutes"

The field value can only be a number

These fields store character sequences (words, texts, etc.)

Database "Electives"

Database "Time Accounting"

Last name, first name

Ivanov Petya

Petrov Vanya

Time tracking

Sidorov Vitya

Time spent

numerical

symbolic

logical


Access 2007 objects

Tables- main database objects.

Requests- these are special structures designed to process database data.

Forms- these are objects with the help of which new data is entered into the database or existing data is viewed.

Reports- these are “vice versa” forms. With their help, data is output to the printer in a convenient and visual form.

Macros - This macro commands.

Modules are software procedures written in Visual Basic.

Modes of operation with Access 2007

There are two different modes when working with any database: design - using the constructor

And operational(custom) – using a wizard.


Elements of a tabular database A database field is a table column containing the values ​​of a specific property A database record is a table row containing a set of property values ​​located in database fields A key field is a field whose value uniquely identifies a record in the table


Basic data types Counter – integers that are set automatically when entering records. These numbers cannot be changed by the user Text - texts containing up to 255 characters Numeric - numbers Date/Time - date or time Currency - numbers in monetary format Boolean - values ​​True (Yes) or False (No) Hyperlink - links to an information resource in Internet (for example, website)










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Table In databases, all information is stored in two-dimensional tables. This is the base database object; all other objects are created based on existing tables (derived objects). Next >>> >>"> >>"> >>" title="Table In databases, all information is stored in two-dimensional tables. This is the basic database object; all other objects are created based on existing tables (derived objects). Next >> >"> title="Table In databases, all information is stored in two-dimensional tables. This is the base database object; all other objects are created based on existing tables (derived objects). Next >>>"> !}


Queries In a DBMS, queries are the most important tool. The main purpose of queries is to select data based on specified conditions. Using a query from the database, you can select information that satisfies certain conditions Next >>> >>"> >>"> >>" title="Queries In a DBMS, queries are the most important tool. The main purpose of queries is to select data based on specified conditions. Using a query from a database, you can select information that satisfies certain conditions Next >>>"> title="Queries In a DBMS, queries are the most important tool. The main purpose of queries is to select data based on specified conditions. Using a query from the database, you can select information that satisfies certain conditions Next >>>"> !}


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. Next >>> >>">


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Macros Macros are used to automate repetitive operations. Recording a macro is done in the same way as in other applications, for example, in MS Word. Next >>> >>"> >>"> >>" title="Macros Macros are used to automate repetitive operations. Recording a macro is done in the same way as in other applications, for example, in MS Word Next >>>"> title="Macros Macros are used to automate repetitive operations. Recording a macro is done in the same way as in other applications, for example, in MS Word. Next >>>"> !}


Modules Modules also serve to automate work with the database. Modules are also called event handling procedures and are written in VBA. Next >>> >>"> >>"> >>" title="Modules Modules are also used to automate work with the database. Modules are also called event processing procedures and are written in VBA. Next >>>"> title="Modules Modules also serve to automate work with the database. Modules are also called event handling procedures and are written in VBA. Next >>>"> !}




Stage 1 Create a new database in the Access application using the command: [File – Create Database...] Next > "> "> " title=" Stage 1 Create a new database in the Access application using the command: [File – Create Database…] Next >"> title="Stage 1 Create a new database in the Access application using the command: [File – Create Database...] Next >"> !}


Stage 2 In the Internet Providers: Database window, select the Tables group of objects, then Create a table in design mode Continue > "> "> " title=" stage 2 In the Internet Providers: Database window, select the Tables group of objects, then Create a table in design mode Next >"> title="Stage 2 In the Internet Providers: Database window, select the Tables group of objects, then Create a table in design mode Continue >"> !}


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Stage 4 After creating the table, its name is added to the database window and it can be easily opened either in Design mode (Design button) or in Table mode (Open button) Next work > "> "> " title="4th stage After creating a table, its name is added to the database window and it can be easily opened either in Design mode (Design button) or in Table mode (Open button) Next work >"> title="Stage 4 After creating the table, its name is added to the database window and it can be easily opened either in Design mode (Design button) or in Table mode (Open button) Next work >"> !}




Stage 1 In the Internet Providers: Database window, select the Forms group of objects. Select Create a form using the wizard Next > "> "> " title=" Stage 1 In the Internet Providers: Database window, select the Forms group of objects. Select Create a form using the wizard Next >"> title="Stage 1 In the Internet Providers: Database window, select the Forms group of objects. Select Create a form using the wizard Next >"> !}


Stage 2 In the Create Forms panel that appears, select the source table in the Tables and Queries window, and in the Available Fields window: - fields for the Form. Click the Next button Next >Next > Next >>> Next >>> Next >> title=" stage 2 In the Create Forms panel that appears, select the source table in the Tables and Queries window, and in the Available Fields window: - fields for the Form. Click on the Next Next button >Next >"> title="Stage 2 In the Create Forms panel that appears, select the source table in the Tables and Queries window, and in the Available Fields window: - fields for the Form. Click the Next button Next >Next >"> !}


Stage 3 In the next panel that appears, use the switches to select the method of placing fields on the Form (for example, in one column). Click the Next button Next >Next > Next >>> Next >>> Next >> title=" Stage 3 In the next panel that appears, use the switches to select the method of placing fields on the Form (for example, in one column). Click the Next Next >Next button"> title="Stage 3 In the next panel that appears, use the switches to select the method of placing fields on the Form (for example, in one column). Click the Next button Next >Next >"> !}


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