Welcome:
To the second learning sequence
“ Database (DB) and Database Management System (DBMS) “
Recap
: In the previous learning sequence, we discussed the basic definitions of
Database subject.
Present learning: We shall explore the following topics:
- What is DB ?
- What is DBMS?
- Advantages of using DBMS.
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What is Database
- A Database is a collection of stored operational
data used by the application systems of some
particular enterprise.
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What is Database
- A Database is a collection of stored operational
data used by the application systems of some
particular enterprise.
- A Database is a collection of related data.
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What is Database
- A Database is a collection of stored operational
data used by the application systems of some
particular enterprise.
- A Database is a collection of related data.
- A database is designed, built, and populated with
data for a specific purpose. It has an intended
group of users and some preconceived
applications in which these users are interested.
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What is Database
- A database can be of any size and of varying
complexity.
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What is Database
- A database can be of any size and of varying
complexity.
- A database may be generated and maintained
manually or it may be computerized.
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Database Management System
- Is a collection of programs that enables users to
create and maintain a database.
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Database Management System
- Is a collection of programs that enables users to
create and maintain a database.
- The DBMS is a general-purpose software system
that facilitates the processes of defining,
constructing, and manipulating databases for
various applications.
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Database Management System
- Defining: a database involves specifying the
data types, structures, and constraints for the
data to be stored in the database.
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Database Management System
- Defining: a database involves specifying the
data types, structures, and constraints for the
data to be stored in the database.
- Constructing: the database is the process of
storing the data itself on some storage medium
that is controlled by the DBMS.
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Database Management System
- Defining: a database involves specifying the
data types, structures, and constraints for the
data to be stored in the database.
- Constructing: the database is the process of
storing the data itself on some storage medium
that is controlled by the DBMS.
- Manipulating: a database includes such
functions as querying the database to retrieve
specific data, updating the database to reflect
changes in the miniworld, and generating reports
from the data.
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Database SYSTEM
We will call the database and DBMS
software together a database system
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Example
UNIVERSITY database for maintaining information
concerning students, courses, and grades in a
university environment.
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Example
UNIVERSITY database for maintaining information
concerning students, courses, and grades in a
university environment
-
define: file (records), data elements, data type ( for
each data element).
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Example
UNIVERSITY database for maintaining information
concerning students, courses, and grades in a
university environment
-
define: file (records), data elements, data type ( for
each data element)
-
construct: store data in the appropriate files (note that
records may be related between files).
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Example
UNIVERSITY database for maintaining information
concerning students, courses, and grades in a
university environment
-
define: file (records), data elements, data type ( for
each data element)
-
construct: store data in the appropriate files (note that
records may be related between files)
- Manipulation: querying, updating.
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Advantages of Using DBMS
1- Controlling Redundancy:
In DBMS there has the ability to control
redundancy which improve the performance of
the query. The DBMS should have the
capability to control this redundancy so as to
avoid inconsistencies among the files.
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Advantages of Using DBMS
2- Restricting Unauthorized Access:
Users or user groups are given account numbers
protected by passwords, which they can use to
gain access to the database through security and
authorization subsystem
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Advantages of Using DBMS
3- Providing Persistent Storage for Program Objects
and Data Structures:
Programming languages typically have complex
data structures, such as record types in PASCAL
or class definitions in C++. The values of
program variables are discarded once a program
terminates, unless the programmer explicitly
stores them in permanent files, which often
involves converting these complex structures into
a format suitable for file storage
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Advantages of Using DBMS
4- Permitting Inference and Actions Using Rules:
Deductive database systems: when database
systems provide capabilities for defining
deduction rules for Inferencing new information
from the stored database facts.
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Advantages of Using DBMS
5- Providing Multiple User Interfaces:
A DBMS provides a variety of user interfaces:query
languages for casual users; programming
language interfaces for application programmers;
forms and command codes for parametric users;
and menu-driven interfaces and natural language
interfaces for stand-alone users.
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Advantages of Using DBMS
6- Enforcing Integrity Constraints:
The simplest type involves specifying a data type
for each data item, and a more complex type
involves specifying that a record in one file
must be related to records in other files.
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Advantages of Using DBMS
7- Providing Backup and Recovery:
Provide facilities for recovering from hardware or
software failures (The backup and recovery
subsystem ).
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Summary: In this learning sequence, we discussed
the following topics:
- what is DB and DBMS?
- Advantages of DBMS.
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END
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