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Database

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Database
DIANA ORAZBAYEVA
Database is an information model that allows you to
store data about a group of objects that have the same
set of properties in an ordered manner. You can
compare a database to a filing cabinet that stores
documents. In other words, a database is a data
warehouse. Databases themselves would not be of
interest if there were no database management
systems (DBMS).
A database management system is a set of language
and software that provides access to data, allows you
to create, change and delete them, ensures data
security, etc. In general, a DBMS is a system that
allows you to create databases and manipulate
information from them. And it provides this access to
the DBMS data through a special language - SQL.
SQL is a structured query language whose main
purpose is to provide an easy way to read and write
information to a database.
Database classification
The nature of the information stored
Factographic databases
Documentary databases
Data storage method
Centralized databases
Distributed databases
Database structure
When creating a database, we strive to
organize information according to
various criteria in order to then extract
the data we need from it in any
combination. This can only be done if
the data is structured. Structuring is a
set of conventions for how data is
presented. It is clear that information
can be structured in different ways.
Depending on the structure, there are
hierarchical, network, relational,
object-oriented and hybrid database
models. The most popular today is the
relational structure, so we will only
mention the rest in passing.
Database
Tabular
Network
Hierarchical
The main information unit of the database is a
table. The database can consist of one table - a
single-table database or of many interconnected
tables - a multi-table database.
A master key must be defined for each database
table. The key value should not be repeated in
different records. For example, in a library
database, such a key is the inventory number of a
book, which does not match for different books.
Basic data types
• Counter - whole numbers 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;
• Monetary - numbers in monetary format,
• Boolean - values ​True (Yes) or False (No);
• Hyperlink - links to an information resource
on the Internet (for example, a Web site).
The database window is one of the main elements of the
Access interface.
Table - This is the basic database object, all other objects are
created based on existing tables (derived objects).
Access database
objects
Requests. In a DBMS, queries are the most important tool.
The main purpose of queries is to select data based on
specified conditions.
Forms. Forms allow you to display the data contained in tables
or queries in a more readable way.
Reports. Reports are designed to print the data contained in
tables and queries in a beautifully designed format.
Macros. Macros are used to automate repetitive operations.
Macro recording is done in the same way as in other
applications, such as Word.
Modules. Modules also serve to automate work with the
database. Modules are also called event procedures and are
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