120 likes | 257 Views
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. Contents. Concept of a Data Base
E N D
Module 7Data 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 Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
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). Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
25060 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. Ahmad Al-Ghoul 2010-2011
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 Ahmad Al-Ghoul 2010-2011
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. Ahmad Al-Ghoul 2010-2011