Describe the basics elements of Database

1. Kandahar University
Database
 Step 1
Data
The word data is derived from the Latin which means ‘to give’; data is real given facts, from
which additional facts can be inferred. Data is a collection of known facts that can be recorded
and that have implicit meanings.
 Step 2
Database
Database is a collection of related data or operational data extracted from any firm or
organization. In other words, a collection of organized data is called database.
 Step 3
DBMS (Database Management System)
DBMS is a collection of programs that enables users to create, maintain, and manipulate a
database. The DBMS is a general purpose software system that facilitates the process of
defining, constructing, and manipulating database.
 Step 4
Database Systems
A database system comprises a database of operational data, together with the processing
functionality required to access and manage that data. The combination of the DBMS and the
database is called database systems.
 Step 5
Database Catalog
A database catalog contains complete description of the databases, database objects, database
structure, details of users, and constraints etc. that are stored.
 Step 6
Program-data independence
In traditional file processing, the structure of the data files is ‘hard-coded” into the programs.
To change the structure of the data file, one or more programs that access that file, should be
changed. The process of changing can introduce errors. In contrast to this more traditional
approach, DBMS access stores the structure in a catalog, separating the DBMS programs and
the data definition. Storing the data and programs separately is known as program-data
independence.

2. RAHMATULLAH DANISH 2
 Step 7
User View
The way in which the database appears to a particular user is called user view.
 Step 8
DBA (Database Administrator)
DBA is a person who is responsible for authorizing access to the database, coordinating and
monitoring its use, and acquiring software and hardware resources as needed.
 Step 9
End User
End users are the people who want to access the database for different purposes like, querying,
updating, and generating reports.
 Step 10
Canned Transactions
Standardized queries and updates on the database using carefully programmed and tested
programs.
 Step 11
Deductive Database System
A deductive database system is a database system that supports the proof-theoretic view of a
database, and, in particular, is capable of deducing are inferring additional facts from the given
facts in the extensional database by applying specified deductive anxious are rules of inference
to those given facts.
 Step 12
Persistent object
Object-Oriented database systems are compatible with programming languages such as c++
and JAVA. An object that is stored in such a way that it survives that termination of the DBMS
program is persistent.
 Step 13
Meta Data
Information about the data is called Meta data. The information stored in the catalog is called
Meta data. The schema of a table is an example of Meta data.
 Step 14
Transaction processing application

3. RAHMATULLAH DANISH 3
A transaction is a logical unit of database. The processing includes one or more database
operations like, insertion, deletion, modification and retrieval. The database operations that
form a transaction can either be embedded within an application program on they can be
specified interactively via a high-level query language such as SQL.
 Step 15
Data model
The data model describes the logical structure of the database and it introduces abstraction in
the DBMS (Database Management System). The data model provides a tool to describe the data
and their relationships.
 Step 16
Database Schema
The database schema describes the overall design of the database. It is a basic structure to
define how the data is organized in the database. The database schema can be depicted by the
schema diagrams.
 Step 17
Database state
The actual data stored in the database in a moment in time is called the database state.
 Step 18
Internal Schema
It is also referred as the Physical level schema. The internal schema represents the structure of
the data as viewed by the DBMS and it describes the physical storage structure of the database.
 Step 19
Conceptual Schema
It is also referred to as the Logical level schema. It describes the logical structure of the whole
database for a group of users. It hides the internal details of the physical storage structure.
 Step 20
External Schema
The external schema referred as User level schema. It describes the data which is viewed by the
end users. This schema describes the part of the database for a user group and it hides the rest
of the database from that user group.
 Step 21
Data independence

4. RAHMATULLAH DANISH 4
The capacity to change the schema at the physical level of a database system without affecting
the schema at the conceptual or external level is called data independence.
 Step 22
DDL
DDL stands for Data Definition Language. It is used to create, alter, and drop the database
tables, views, and indexes.
 Step 23
DML
DML stands for Data Manipulation Language. It is used to insert, retrieve, update, and delete
the records in the database.
 Step 24
SDL
SDL stands for Storage Definition Language. It is used to specify the internal schema of the
database and specify the mapping between two schemas.
 Step 25
VDL
VDL stands for View Definition Language. It specifies the user views and their mappings to the
logical schema in the database.
 Step 26
Query Language
The query language is a high-level language used to retrieve the data from the database.
 Step 27
Host Language
The host language is used for application programming in a database. The DML commands are
embedded in a general-purpose language to manipulate the data in the database.
 Step 28
Data Sublanguage
The data manipulation language commands are embedded in a general-purpose language to
manipulate the data such as insert, update, and delete operations in the database, here the DML
is referred as a data sublanguage.
 Step 29
Database utility

5. RAHMATULLAH DANISH 5
The database utility is a software module to help the DBA (Database Administrator) to manage
the database.
 Step 30
Catalog
The catalog stores the complete description of the database structure and its constraints.
 Step 31
Client/server architecture
The client/server architecture is a database architecture and it contains two modules. A client
module usually a PC that provides the user interface. A server module can respond the user
queries and provide services to the client machines.
 Step 32
Three-tier architecture
The three-tier architecture consists of three layers such as client, application server, and
database server. The client machine usually contains the user interface and the intermediate
layer (application layer) running the application programs and storing business rules. The
database layer stores the data.
 Step 33
n-tier architecture
The n-tier architecture consists of four or five tiers. The intermediate layer or business logic
layer is divided into multiple layers. And distributing programming and data throughout a
network.