Ch. 1 Flashcards
Data
Stored representations of objects and events that have meaning and importance in the user’s environment.
Database
An organized collection of logically related data.
Stored in standardized, convenient form
Managed by a universal controlling agent called DBMS (Single agent instead of multiple applications)
Database Management System
Software used to create, maintain, and provide controlled access to user databases
Primary purpose of a DBMS is to provide a systematic method of creating, updating, storing, and retrieving the data stored in a database. It enables end users and application programmers to share data, and it enables data to be shared among multiple applications rather than propagated and stored in new files for every new application
Data Models
Graphical systems used to capture the nature and relationships among data
A typical data model is made up of entities, attributes, and relationships and the most common data modeling representation is the entity-relationship model
Metadata
“data about data”
Primary mechanism for providing context for data
Data that describe the properties or characteristics of end-user data and the context of that data.
Some of the properties that are typically described include data names, definitions, length (or size), and allowable values. Metadata describing data context include the source of the data, where the data are stored, ownership (or steward- ship), and usage.
Database Application
An application program (or set
of related programs) that is used to perform a series of database activities (create, read, update, and delete) on behalf of database users.
Entity
A person, a place, an object,
an event, or a concept in the user environment about which the organization wishes to maintain data.
Relational Database
A database that represents data as a collection of tables in which all data relationships are represented by common values in related tables.
Establishes the relationships between entities by means of common fields included in a file, called a relation.
Data Independence
Separation of data descriptions (metadata) from the application programs that use the data
Repository
A centralized knowledge base of all data definitions, data relationships, screen and report formats, and other system components.
User View
Logical description of some portion of the database that is required by a user to perform some task
Often developed by identifying a form or report that the user needs on a regular basis.
For example, an employee working in human resources will need access to confidential employee data; a customer needs access to the product catalog available on Pine Valley’s Web site. The views for the human resources employee and the customer are drawn from completely different areas of one unified database.
Data modeling and design tools
Automated tools used to design databases and application programs.
These tools help with creation of data models and in some cases can also help automatically generate the “code” needed to create the database.
enterprise data modeling
Establishes the range and general contents of organizational databases.
Its purpose is to create an overall picture or explanation of organizational data, not the design for a particular database.
A particular database provides the data for one or more information systems, whereas an enterprise data model, which may encompass many databases, describes the scope of data maintained by the organization. In enterprise data modeling, you review current systems, analyze the nature of the business areas to be supported, describe the data needed at a very high level of abstraction, and plan one or more database development projects.
Systems Development Life Cycle
A traditional process for conducting an information systems development project
The SDLC is a complete set of steps that a team of information systems professionals, including database designers and programmers, follow in an organization to specify, develop, maintain, and replace information systems.
enterprise resource planning (ERP)
A business management system that integrates all functions of the enterprise, such as manufacturing, sales, finance, marketing, inventory, accounting, and
human resources. ERP systems are software applications that provide the data necessary for the enterprise to examine and manage its activities.
Data warehouse
Data warehouses collect content from the various operational databases, including personal, workgroup, department, and ERP databases.
Data warehouses provide users with the opportunity to work with historical data to identify patterns and trends and answers to strategic business questions.
Conceptual Schema
A detailed, technology- independent specification of the overall structure of organizational data.
The output of the conceptual modeling phase is a conceptual schema.
Logical Schema
The representation of a database for a particular data management technology.
Logical representation of a database for a particular database model (e.g., relational data models)
Physical schema
A physical schema is a set of specifications that describe how data from a logical schema are stored in a computer’s secondary memory by a specific database management system.
There is one physical schema for each logical schema
Even more detailed specification for how data is stored in a database (e.g., organization of physical records, choice of file organizations, use of indexes, etc.))
Prototyping
An iterative process of systems development in which requirements are converted to a working system that is continually revised through close work between analysts and users.
agile software development
An approach to database and software development that emphasizes “individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and response to change over following a plan.”
A conceptual representation of database development
Business Processes -> Data Models -> Database
2 IS Development Approaches
SDLC & Prototyping
Three-Schema Architecture
External, Conceptual, Internal
Guideline for describing the structure of data
Internal Schema
Describes how the data is stored / the physical storage structure of the database & complete details of data storage and access
Made up of Logical & Physical Schema
External Schema
Describes how a piece of data appears on user’s screen, hides the rest of the database from user group, only shows what the user is interested in (GUI windows)
