Test 1 Flashcards
Traditional applications?
Numeric and textual databases
Recent applications?
Multimedia
GIS
Biological
Data warehouse
Mobile
Real time
Social Networks started capturing a lot of information about people and about communications among people-posts, tweets, photos, videos in systems such as:
- Linked-In
Some part of the real world about which data is stored in a database. For example, student grades and transcripts at a university.
Mini-world
A database is a coherent collection of data with some inherent meaning . A random assortment of data cannot correctly be referred to as a database
Logically coherent
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.
Designed with a purpose
What is a database?
Mini-world
Logically coherent
Designed with a purpose
A collection of related data
Database
Known facts that can be recorded and have an implicit meaning
Data
A software package/ system to facilitate the creation and maintenance of a computerized database.
Database management system (DBMS)
The DBMS software together with the data itself. Sometimes, the applications are also included
Database system
Impact of databases and database technology
Businesses,
service industries,
education,
personalized application,
social networks,
environmental/scientific application,
medicine
Typical DBMS functionality
Define
Construct
Manipulating
Processing & sharing
What does manipulating a database intel?
Retrieval
Modification
Accessing the database through web application
Application interact with a database by generating:
Queries
Transactions
Access different parts of data and formulate the result of a request
Queries
May read some data and “update” certain values or generate new data and store that in the database
Transactions
Applications must not allow __________ users to access data
Unauthorized
Must keep up with changing user requirements against the database
Application
DBMS may additionally provide?
Protection/security measures to prevent unauthorized access
“Active ” processing to take internal action on data
Prsentation/visualization of data
Maintenance of the database
Maintenance of the database and associated programs over the lifetime of the database application
Called Database, software, and system maintenance
A DBMS _________ stores the description of a particular database.
The description is called:
Catalog
Metadata
Insulation between programs and data are called:
Program-data independence
Allows changing data structures and storage organization without having to change the DBMS access programs
Insulation between programs and data
Some newer systems such as a few __________ systems need no meta- data: they store the data definition within its structure making it self describing
NOSQL
is used to hide storage details and present the users with a conceptual view of the database.
A data model
refer to the data model constructs rather than data storage details
Programs
Each user may see a different view of the database, which describes _______ the data of interest to that user .
only
Allowing a set of _________________ to retrieve from and to update the database .
concurrent users
within the DBMS guarantees that each transaction is correctly executed or aborted
Concurrency control
ensures each completed transaction has its effect permanently recorded in the database
Recovery subsystem
is a major part of database applications. This allows hundreds of concurrent transactions to execute per second .
OLTP (Online Transaction Processing)
Users may be divided into:
Called: actors in the scene
Those who control the database, who develop/maintain database application
Called: workers behind the scene
Those who develop the DBMS software, related tools, and computer systems operators
Actors on the scene include
Database administrators
Database designers
•Responsible for authorizing access to the database, for coordinating and monitoring its use, acquiring software and hardware resources , controlling its use and monitoring efficiency of operations.
•Responsible to define the content, the structure, the constraints, and functions or transactions against the database. They must communicate with the end-users and understand their needs.
Database administrators
Database designers
Actors on the scene include:
End-users
They use the data for queries, reports and some of them update the database content.
End-users:
End-users can be categorized into:
- access database occasionally when needed
- they make up a large section of the end -user population .
- Casual
- Naïve or Parametric
These include business analysts, scientists, engineers, others thoroughly familiar with the system capabilities. Many use tools in the form of software packages that work closely with the stored database.
Sophisticated
Mostly maintain personal databases using ready-to-use packaged applications. An example is the user of a tax program that creates its own internal database. Another example is a user that maintains a database of personal photos and videos.
Stand-alone
This category currently accounts for a very large proportion of the IT work force.
System Analysts and Application Developers
They understand the user requirements of naïve and sophisticated users and design applications including canned transactions to meet those requirements.
System Analysts
Implement the specifications developed by analysts and test and debug them before deployment .
Application Programmers
There is an increasing need for such people who can analyze vast amounts of business data and real- time data (“Big Data”) for better decision making related to planning , advertising , marketing etc.
Business Analysts
Design and implement DBMS packages in the form of modules and interfaces and test and debug them. The DBMS must interface with applications, language compilers, operating system components, etc.
System Designers and Implementors
Design and implement software systems called tools for modeling and designing databases, performance monitoring, prototyping, test data generation, user interface creation, simulation etc. that facilitate building of applications and allow using database effectively.
Tool Developers
They manage the actual running and maintenance of the database system hardware and software environment
Operators and Maintenance Personnel
Advantages of using the database approach:
Controlling redundancy in data storage and in development and maintenance efforts.
Restricting unauthorized access to data. Only the DBA staff uses privileged commands and facilities.
Providing persistent storage for program Objects
Providing Storage Structures (e.g. indexes ) for efficient Query Processing
Providing optimization of queries for efficient processing.
Providing backup and recovery services .
Providing multiple interfaces to different classes of users .
Representing complex relationships among data .
Enforcing integrity constraints on the database .
Drawing inferences and actions from the stored data using deductive and active rules and triggers .
This is very crucial for the success of database applications in large organizations. _________ refer to data item names , display formats , screens , report structures , meta-data (description of data), Web page layouts , etc.
Standards
Implications of using the database approach:
Potential for enforcing standards
Reduced application development time
Flexibility to change data structure
Availability of current information
Economies of scale
When not to use a DBMS
Main inhibitors (costs) of using a DBMS
When a DBMS may be unnecessary
When a DBMS may be infeasible
When no DBMS may suffice