Data facts, text, graphics, images, sound, and video segments that have meaning in the user s environment. Example: a listing of students Information data that have been processed in such a way as to increase the knowledge of the person who uses the data. Example: student data coul d be analyzed and summarized through the use of statistical measures. Metadata data that describe the properties or characteristics of other data but do not include that data. Some of these properties incl ude data definitions, data structures, and rules or constraints.
Data facts, text, graphics, images, sound, and video segments that havemeaning in the user s environment.
Example: a listing of studentsInformation data that have been processed in such a way as to increase theknowledge of the person who uses the data.
Example: s tudent data could be analyzed and summarizedthrough the use of statistical measures.Metadata data that describe the properties or characteristics of other databut do not include that data. Some of these propert ies include datadefinitions, data structures, and rules or constraints.
Database an organized collection of logically related data.Data System employ a combination of persons, methods and materialsto process raw data about an enterprise into significant informationso as to providea basis for management decision.
Data Element general class or category of data also known as data item,data field or attributes.
Key Data Element data element that uniquely identifies the record.Data R ecord collection of values taken by related data element.Data File collection of data records.
Database Approach emphasizes the integration andsharing of data across the organization. Thisapproach requires a major reorientation inthought process (paradigm shift), starting withtop management.
Database Application an application program (or setof related programs) that is used to perform aseries of database activities(create, read, update,delete) on behalf of database users.
1. Personal databases designed to supportone user.2. Workgroup databases databases wherein a relatively small team of
people collaborate on the same project or application or on a group of similar projects or applications.
3. Department databases designed to support the various functions
and activities of a department.4. Enterprise databases databases whose scope is the entire
organization or enterprise intended to support organization-wideoperations and decision making.
a. Enterprise resource planning(E R P) systems a business
management system that integrates all functions of the enterprise,such as manufacturing, sales, finance, marketing, inventory,accounting, and human resources.b. Data warehouse an integrated decision support database whosecontent is derived from the variousoperational databases.
1. Program-data independenceData independence separation of data descriptions from the
application programs that uses the data.2. Minimal data redundancy 3. Improved data redundancy 4. Improved data sharing5. Increased productivity of application development
6. Enforcement of standards7. Improved data quality
C onstraint a rule that cannot be violated by database users.8. Improved data accessibility and responsiveness9. R educed program maintenanceMaintenance refers to modifying or rewriting old programs to make
them conform to new data formats, access methods and so forth.
1. C omputer-Aided Software Engineering Tools ( C ASE) automated toolsused to design databases and application programs.
2. R epository centralized knowledge base containing all data definitions,screen and report formats, and definitions of other organizations andsystem components.
3. Database Management System (DBMS)- commercial software system used to create, maintain and providecontrolled access to the database and also to the repository.
4. Database a shared collection of logically related data.
5. Application programs computer programs that are used to create andmaintain the database and provide information to users.
1. Enterprise modeling the first step in database development in which the scope and general contents of a database are specified.
2. C onceptual database design analysis of the over-all datarequirements for a specific information system. This system might bethe topic of a particular user request to modify an existing system orto build a new system, or it might be the result of the identificationof a new database from enterprise modeling.
3. Logical database design perform the detailed review of thebusiness processes supported by the database, analyze eachindividual report, transaction and so on.
4. Physical database design and creation decide on the organizationof the database in computer storage and define the physicalstructures to the database management system.
5. Database implementation writing, testing and installing theprograms that process the database for data capture and reporting.
6. Database maintenance evolve the database. Add, delete, or changecharacteristics of the structure of a database in order to meetchanging business conditions, to correct errors in database designmade in earlier steps or to improve the processing speed of adatabase applications.
A database security manager is the most important asset to maintainingand securing sensitive data within an organization. Database security managers are required to multitask and juggle a variety of headachesthat accompany the maintenance of a secure database.
If you own a business it is important to understand some of the databasesecurity problems that occur within an organization and how to avoidthem. If you understand the how, where, and why of database security you can prevent future problems from occurring.
Database Security Issuesy Daily Maintenance: Database audit logs. These unauthorized
applications are often difficult to identify and allow hackers acquiredaily review to make certain that there has been no data misuse. This
requires overseeing database privileges and then consistently updatinguser access accounts. A database security manager also providesdifferent types of access control for different users and assesses newprograms that are performing with the database. If these tasks areperformed on a daily basis, you can avoid a lot of problems with usersthat may pose a threat to the securityof the database.
y Varied Security Methods for Applications: More often than notapplications developers will vary the methods of security for differentapplications that are being utilized within the database. This can createdifficulty with creating policies for accessing the applications. Thedatabase must also possess the proper access controls for regulating the varying methods of security otherwise sensitive data is at risk.
y Post- U pgrade Evaluation: When a database is upgraded it is necessary for the administrator to perform a post-upgrade evaluation to ensurethat security is consistent across all programs. Failure to perform thisoperation opens up the database to attack.
y Split the Position: Sometimes organizations fail to split the dutiesbetween the IT administrator and the database security manager.Instead the company tries to cut costs by having the IT administratordo everything. This action can significantly compromise the security of the data due to the responsibilities involved with both positions. The ITadministrator should manage the database while the security managerperforms all of the daily security processes.
y Application Spoofing: Hackers are capable of creating applications thatresemble the existing applications connected to the database. Theseunauthorized applications are often difficult to identify and allowhackers access to the database via the application in disguise.
y Manage U ser Passwords: Sometimes IT database security managers will
forget to remove IDs and access privileges of former users which leadsto password vulnerabilities in the database. Password rules andmaintenance needs to be strictly enforced to avoid opening up thedatabase to unauthorized users.
y Windows O S Flaws: Windows operating systems are not effective whenit comes to database security. O ften theft of passwords is prevalent as well as denial of service issues. The database security manager can takeprecautions through routine daily maintenance checks.
These are just a few of the database security problems that exist withinorganizations. The best way to avoid a lot of these problems is toemploy qualified personnel and separate the security responsibilitiesfrom the daily database maintenance responsibilities.
The most important security measures of data management softwarefollows:
1. Views or subschemas, which restrict user views of the database. A view is a subset of the database that is presented to one or more users.
It is created by querying one or more of the base tables, producing adynamic result table for the user at the time of the request.
2. Domains, assertions, checks, and other integrity controls defined asdatabase objects, which are enforced by the DBMS during databasequerying and updating. Integrity controls protect data fromunauthorized use and update. They limit the values a field may hold,limit the actions that can be performed on data, or trigger theexecution of some procedure, such as placing an entry in a log torecord which users have done what with which data.
Domain a way to create a user-defined data type. O nce a domain isdefined, any field can be given that domain as its data type.
Assertion powerful constraint that enforce certain desirable databaseconditions.
Trigger includes an event, condition, and action which can do thefollowing:
y
Prohibit inappropriate actionsy C ause special handling procedures to be executedy C ause a row to be written to a log file to echo important information
about the user and a transaction being made to sensitive data.3. Authorization rules, which identify users and restrict the actions they
may take against a database. These are controls incorporated in thedata management system that restrict access to data and also restrictthe actions that people may take when they access data.
4. U ser-defined procedures, which define additional constraints orlimitations in using a database. Some DBMS products provide user
exits (or interfaces) that allow system designers or users to createtheir own user-defined procedures for security.
Introduction to the E-R Model An entity-relationship data model (or E- R Model) is a detailed, logical
representationof the data for an organizationor for a business area.- normally expressed as an entity-relationship diagram (or E- R
diagram)Entity a person, place, object, event, or concept in the user environment
about which the organization wishes to maintain data.Entity type (or entity class) is a collection of entities that share common
propertiesor characteristics.Entity instance (or instance) is a single occurrence of an entity type. Attribute a property or characteristic of an entity that is of interest to
the organization.C andidate key an attribute or combination of attributes that uniquely
Primary key a candidate key that has been selected as the identifier foran entity type.
Multi-valued attribute can have more than one value for each entity instance.
R elationship an association between the instance of one or more entity types that is of interest to the organization.Degree of a relationship the number of entity types that participate in
that relationship.a) U nary relationship also called a recursive relationship, is a
relationship between the instances of one entity type.b) Binary relationship a relationship between instances of two entity
types and is the most common type of relationship encountered indata modeling.
Properties of Relations1. Entries in columns are atomic (or single-valued).2. Entries in columns are from the same domain.3. Each row is unique (no duplicate rows).
4. The sequence of columns (left to right) is insignificant.5. The sequence of rows (top to bottom) is insignificant.
Well-Structured Relation: A relation that contains a minimum amount of redundancy and allows users to
insert, modify, and delete the rows in a table without errors or inconsistencies. Anomalies: Errors or inconsistencies that may result when a user attempts to
update a table that contains redundant data.Three types of anomalies: insertion, deletion, and modification anomalies.
Functional dependency: A particular relationship between two attributes. For any relation R ,attribute B is functionally dependent on attribute A if, for every valid instance of A, that value of A uniquely determines the value of B. The functional dependence of B on A isrepresented as A--->B.
Example:
SSN NAME,ADDR
ESS,BIR
THDATE: A persons name, address, and birthdate arefunctionallydependent on that person s Social Security number.Determinant: The attribute on the left-hand side of the arrow in a functional dependency; A
is a determinant in the following functional dependency: A B.C omposite key: A primary key that contains more than one attribute.Example:
EMPLO YEE2(EMPID,NAME,DEPT,SALA R Y,COUR SE,DATE CO MPLETED).
