Chapter 2 - Data & Info mgmt
Attribute
A characteristic of an entity.
Many-to-many relationship
A relationship where multiple instances of one entity are associated with multiple instances of another entity.
One-to-one relationship
A relationship where one entity is associated with exactly one instance of another entity.
One-to-many relationship
A relationship where one entity is associated with multiple instances of another entity.
Constraint
A restriction placed on the data.
User Interface
Allows interaction with data and generates SQL.
Entity
Anything about which data are to be collected and stored.
Common Attributes
Attributes used to relate different tables.
Inheritance
Child objects inherit from parent classes.
Object-Oriented Data Model (OODM)
Combines data and relationships in objects.
Extended Relational Data Model (ERDM)
Combines features of relational and OO models.
Sources of Business Rules
Company managers, policy makers, department managers, written documentation, and direct interviews with end users.
Network Model
Created to represent complex data relationships more effectively than the hierarchical model.
Internal Model
Database representation as seen by DBMS.
Data Management Language (DML)
Defines the environment in which data can be managed.
Relationship
Describes an association among entities.
Physical Model
Describes how data is physically stored.
Business Rules
Descriptions of policies, procedures, or principles within a specific organization.
Relational Model
Developed by E.F. Codd (IBM) in 1970, consisting of tables (relations) with rows and columns.
Hierarchical Model
Developed in the 1960s to manage large amounts of data for manufacturing projects.
Tuple
Each row in a relation.
Data Definition Language (DDL)
Enables the administrator to define the schema components.
External Model
End users' view of the data environment.
Object-Oriented Extensions
Enhancements to relational model using OO concepts.
Member (in Network Model)
Equivalent to the hierarchical model's child.
Owner (in Network Model)
Equivalent to the hierarchical model's parent.
SQL Engine
Executes all database queries.
Translating Business Rules
Generally, nouns translate into entities and verbs translate into relationships among entities.
Conceptual Model
Global view integrating all external views.
Unified Modeling Language (UML)
Graphical language for modeling systems.
Entity Relationship Diagram (ERD)
Graphical model of database components.
Classes
Groups of similar objects with shared attributes.
Relational Database Management System (RDBMS)
Hides complexity from the user by managing all the physical details.
SQL-based Application
Involves user interface, tables, and SQL engine.
Data Abstraction
Levels of detail in database design.
Big Data
Manages large amounts of web-generated data.
Naming Conventions
Names should make the object unique and distinguishable from other objects.
NoSQL Databases
Not based on relational model, supports scalability.
Attributes
Properties that describe an object.
Data Modeling
Reduces complexities of database design.
Data Model
Relatively simple representations of complex real-world data structures.
Extensible Markup Language (XML)
Standard for data exchange on the Internet.
Entity Relationship Model
Standard for data modeling introduced by Chen.
Importance of documenting Business Rules
Standardizes company's view of data and serves as a communications tool between users and designers.
Relational Table
Stores a collection of related entities.
Connectivity
Type of relationship between entities.
Chen Notation
Uses diamonds for relationships in ERD.
Network Data Model
Uses sets for 1:M and M:M relationships.
Crow's Foot Notation
Uses symbols to represent connectivity in ERD.
Relational Diagram
Visual representation of entities and relationships.
