A database, or db, is an organized collection of information that allows computer programs to efficiently retrieve data, structured using fields, records, and files. Various types of databases exist, including in-memory, active, cloud, distributed, and document-oriented databases, each serving different applications and functionalities. Database management systems (DBMS) are essential for managing these databases, enabling interactions through various languages and performed by database administrators to ensure data integrity.

1. Database
A database, often abbreviated as DB, is a collection of
information organized in such a way that a computer
program can quickly select desired pieces of data.

2. Fields, Records and Files
• You can think of a traditional database as an electronic filing system,
organized by fields, records, and files.
• A field is a single piece of information; a record is one complete set of
fields; and a file is a collection of records.
• For example, a telephone book is analogous to a file. It contains a list of
records, each of which consists of three fields: name, address, and telephone
number.

3. Classification of Database
• One way to classify databases involves the type of their contents, for
example: bibliographic, document-text, statistical, or multimedia objects.
• Another way is by their application area, for example: accounting, music
compositions, movies, banking, manufacturing, or insurance.
• A third way is by some technical aspect, such as the database structure or
interface type. This section lists a few of the adjectives used to characterize
different kinds of databases.

4. Classification (Cont.)
1. In-Memory Database
• An in-memory database is a database that primarily resides in main
memory, but is typically backed-up by non-volatile computer data storage.
• Main memory databases are faster than disk databases, and so are often used
where response time is critical, such as in telecommunications network
equipment.

5. Classification (Cont.)
2. Active Database
• An active database includes an event-driven architecture which can respond
to conditions both inside and outside the database.
• Possible uses include security monitoring, alerting, statistics gathering and
authorization. Many databases provide active database features in the form
of database triggers.

6. Classification (Cont.)
3. Cloud Database
• A cloud database relies on cloud technology.
• Both the database and most of its DBMS reside remotely, "in the cloud",
while its applications are both developed by programmers and later
maintained and used by end-users through a web browser and Open APIs.

7. Classification (Cont.)
• A deductive database combines logic programming with a relational
database.
• A distributed database is one in which both the data and the DBMS span
multiple computers.
• A document-oriented database is designed for storing, retrieving, and
managing document-oriented, or semi structured, information. Document-
oriented databases are one of the main categories of NoSQL databases.

8. Database Interaction
• Hypertext
• Database Management System
• Database Administrator
• Database Engine
• Database Server
• Database language

9. Hypertext
• An alternative concept in database design is known as Hypertext.
• In a Hypertext database, any object, whether it be a piece of text, a picture,
or a film, can be linked to any other object.
• Hypertext databases are particularly useful for organizing large amounts of
disparate information, but they are not designed for numerical analysis.

10. Database Management System
• To access information from a database, you need a database management
system (DBMS).
• This is a collection of programs that enables you to enter, organize, and
select data in a database.
• Increasingly, the term database is used as shorthand for database
management system. There are many different types of DBMSs, ranging
from small systems that run on personal computers to huge systems that run
on mainframes.

11. Database Administrator
• A database administrator (DBA) is a specialized computer systems
administrator who maintains a successful database environment by directing
or performing all related activities to keep the data secure.
• The top responsibility of a DBA professional is to maintain data integrity.
This means the DBA will ensure that data is secure from unauthorized access
but is available to users.

12. Database Engine
• The part of a database management system (DBMS) that actually stores and
retrieves data.
Database Server
• Database server is the term used to refer to the back-end system of a
database application using client/server architecture. The back-end,
sometimes called a database server, performs tasks such as data analysis,
storage, data manipulation, archiving, and other non-user specific tasks.

13. Database Language
• Data control language (DCL) – controls access to data;
• Data definition language (DDL) – defines data types such as creating,
altering, or dropping and the relationships among them;
• Data manipulation language (DML) – performs tasks such as inserting,
updating, or deleting data occurrences;
• Data query language (DQL) – allows searching for information and
computing derived information.