Vocab Quiz 1 Flashcards
Data
Known facts that can be recorded and have implicit meaning
Database
A collection of related data
Miniworld or UoD
Represents some aspect of the real world
Logically coherent
There is a rhyme and reason to why its there
* Random assortments of data is not a database
* Designed, built, and populated with data for a specific purpose
DMBS
A computerized system that enables users to create and maintain a database
Defining a database
Specifying types, structures, constrains of data to be stored within the database
Metadata
data about the data (definitions, dictionary, etc)
Constructing a DMBS
The process of storing the data on some storage medium that is controlled by the DBMS
Manipulating functions
Querying, updating, generating reports
Sharing
Allows access to database
Application program
Accesses the database by sending queries to the DBMS
Queries
Cause data to be retrieved
Transaction
May cause some data to be read and some data to be read into the database
System Protection
Protect against hardware or software malfunction
Security Protection
Against unauthorized or malicious access
Database System
The database and DBMS software together
Describe a Database
- Elements, types, Information System
Conceptual design
Entity Relationship model
Logical design
expressed in a data model
Physical Design
Storing and accessing DB recs - miniworld created
Database Approach
Define once and access repeatedly
DBMA catalog
Stores a complete definition or description of the database structure and contains - stores metadata
Data Abstraction
Allows for program data and operation independence - suppression of details between organization and storage
Program-data Independence
DB catalog separate from access programs
Program-operation independence
application programs operate on the data by invoking these operations through name and arguments, regardless of how the operations are implemented
Data model
Type of data abstraction that provides a conceptual representation (no details of data storage and implementation)
Concurrency control software
Several users updating the database is correct
Online Transaction Processing applications
Airline agents booking tickets
Transaction
Executing program that includes one or more data base accesses - reading or updating records
Database Administrators
Authorize access, monitor its use, and acquire software and hardware resources as needed
Database Designers
Identify the data to be stored, choose appropriate structures to represent and store data
End Users
People whose jobs require access to the database for querying, updating, and generating reports
Casual End Users
Occasional users who may need something different everytime
Naive or Parametric End Users
Revolves around constant querying and updating a database, using standard queries
Canned Transactions
Bank customers and tellers check account balances and post withdrawals and deposits
Sophisticated End Users
Very familiar with the DBMS and have more complex requirements
- engineers, scientists etc
Standalone End Users
Ready made program packages that provide ease of use menus or GUIs
System Analyst
Determine requirements for end users
Data Model
Collection of concepts that can be used to describe the structure of a database
Dynamic Aspect or behavior
Allows designer to specify valid user-defined operations
High-level Data Models (conceptual data models)
Close to the way many perceive data
Representational (implementation)
Easily understood by end users
- use record structures
Low level (physical data models)
Concepts that describe the details of how data is stored on the computer storage media
Represents info such as record formats, record orderings, and access paths
Entity
Represents a real-world object or concept
Attribute
Represents some property of interest that further describes an entity
Access Path
search structure that makes the search for particular database record efficient such as indexing or hashing
Index
Example of an access path that allows direct access to data using an index term or keyword
Self-describing models
- Combines a description of the data with the data values themselves
- Models include XML, NOSQL systems
Schema
Description of Database - specified during db design and does not change frequently unless there is a schema evolution
Schema Diagram
displays structure of each record type
Database state, snapshot, occurrences, instances
The data in the database at a particular moment in time - extension of the schema
Internal level
Describes the physical storage structure of the database
Conceptual level
Describes the structure of the whole database of a community of users
- Representational data model is usually used to describe the entities, data types, relationships, user operations and constraints
External or view level
Includes a number of external schemas or user views - describes the part of the database that a particular user group is interested in and hides the rest of the database from the user group
Data definition language
Used in DBMSs where no strict separation levels are maintained
Storage Definition Language
Used to specify the internal schema
View Definition Language
Used to specify views and their mappings to the conceptual schema
Data Manipulation language
Set of operations provided by the DBMS - users use this to manipulate the database
SQL
- combo of DDL, VDL, and DML
Database Interfaces
- Menu-based interfaces for web clients
- Apps for mobile devices
- Forms-based INterface
- Graphical User Interfaces
- Natural Language Interfaces
- Keyword-based Database Search
- Speech Input and Output
- Interfaces for Parametric Users
- Interfaces for the DBA
Database Systems Utilities
Database Utilities help the DBA manage the database system
- Utilities have the following types of functions:
- Loading
- Backup
- Database storage reorganization ( create new access paths and improve performance if needed)
- Performance Monitoring - Usage and stats
Data dictionary system
Information repository
Application Development Environments
- Provide an environment for developing database applications and facilities that help in many areas of db systems (DB design, GUI development, querying/updating, etc)
Communication Facilities
Allow remote access to the database system site through computer terminals, workstations or personal computers
Centralized DBMS
All the DBMS functionality, application program execution, and user interface processing carried out on one machine (not feasible)
Client/Server Architecture
Developed to deal with computing environments in which a large number of PCs, workstations, file servers, printers, database servers, web servers, e-mail servers, and other software and equipment are connected via a network.
Specialized servers
file server, printer server, web server - all accessed by client machines
