Module 7
Data Base Security
MModified by :Ahmad Al Ghoul
PPhiladelphia University
FFaculty Of Administrative & Financial Sciences
BBusiness Networking & System Management Department
RRoom Number 32406
EE-mail Address: ahmad4_2_69@hotmail.com
Network Security
Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
1
Contents
 Concept of a Data Base
 Components of Data Bases
 Advantages of Using Data Bases
 Security Requirements
 Integrity of the Data Base
 Element Integrity
 Field Checks
 Access Control
 Change Log
Network Security
Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
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Concept of a Data Base
 Collection of data and a set of rules that organise the data
by specifying certain relationships among the data.
 The data items are stored in a file
 User is not concerned with the precise physical format of
the file.
 A data base administrator is the person
– who defines the rules that organise the data
– Controls who should have access to what parts of the data
 The user interacts with the database through a program
called data base manager or DBMS (front-end).
Network Security
Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
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Components of Data Bases
 The data base file consists of
– Records: contains one related group of data
– Each record contains fields or elements
 A data base can be viewed as a two-
dimensional table
 The logical structure of a data base is called
a schema
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Philadelphia
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Ahmad Al-Ghoul 2010-2011
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Components of Data Bases
 The name of each column is called an attribute of the data
base.
 A relation is a set of columns.
 Users interact with data base managers through commands
that retrieve, modify, add or delete fields and records of the
data base
– Commands are called a query
 DBMSs have precise rules of syntax for queries.
SELECT NAME = ‘AYŞE’
retrieves all records having the value AYŞE in the NAME field.
 The result of executing a query is a subschema
Network Security
Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
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Advantages of Using Data Bases
 Shared access
– Many users can use one common, centralised set of data
 Min. Redundancy
– Individual users do not have to collect and maintain their own sets
of data
 Consistency
– A change to data value affects all users of data value
 Integrity
– Values are protected against accidental or malicious incorrect
changes
 Controlled access
– Only authorised users are allowed to view or modify data values
Network Security
Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
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Security Requirements
 Physical data base integrity
– İmmune to power failures
 Logical data base integrity
– Structure is preserved
 Element integrity
– Data contained in each element is correct
 Auditibility
– Trace who accessed/ modified elements
 Access control
– User is allowed to access to only authorised data
 User authentication
– To ensure every user is positively identified
 Availability
– Users can access the data base in general and all the data for which they
are authorised
Network Security
Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
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Integrity of the Data Base
 Trust the accuracy of the data values
 Updates are performed only by authorised
individuals
 Data must be protected from corruption
– The whole data base is damaged
– Individual data items are unreadable
 Integrity of the data base is the responsibility of
the DBMS
 Periodic back-ups of a data base
 DBMS must maintain a log of transactions
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Element Integrity
 Authorised users are responsible for putting
correct data into the data base
– Mistakes in collecting data
– Mistakes in computing results
– Mistakes in entering data
 The DBMS maintains the integrity by:
– Applying field checks
– Access control
– Change log
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Field Checks
 Test for appropriate values in a position
– Numeric
– Uppercase letter
– A set of acceptable characters
 The check ensures that a value falls within
specified bounds or is not greater thatn the sum
of the values in two other fields
 Prevents simple errors as the data is enetered.
Network Security
Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
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Access Control
 A data base may contain data from different
sources
– Redundant data might have been stored in
many places
 Data bases have led to the collection and
control of this data at one central source
– Who has authorisation to update which
elements
– Policy issues
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Philadelphia
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Ahmad Al-Ghoul 2010-2011
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Change Log
 A list of every change made to the data base
 The log contains
– Original
– Modified values
 With this log a data base administrator can
undo any changes that were in error.
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Philadelphia
Universityl
Ahmad Al-Ghoul 2010-2011
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