Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
38 Cards in this Set
- Front
- Back
Suppression of details of data organization and storage
|
Data abstraction
|
|
Highlighting of the essential features for an improved understanding of data
|
Data abstraction
|
|
Collection of concepts that describe the structure of a database
|
Data model
|
|
Provides means to achieve data abstraction
|
Data model
|
|
Specify retrievals and updates on the database
|
Basic operations
|
|
Allows the database designer to specify a set of valid operations allowed on database objects
|
Dynamic aspect or behavior of a database application
|
|
Close to the way many users perceive data
|
High-level or conceptual data models
|
|
Describe the details of how data is stored on computer storage media
|
Low-level or physical data models
|
|
Easily understood by end users
Also similar to how data organized in computer storage |
Representational data models
|
|
Represents a real-world object or concept
|
Entity
|
|
Represents some property of interest
Further describes an entity |
attribute
|
|
Represents an association among the entities
|
Relationship among two or more entities
|
|
Used most frequently in traditional commercial DBMSs
|
Relational data model
|
|
New family of higher-level implementation data models
Closer to conceptual data models |
Object data model
|
|
Describe how data is stored as files in the computer
|
Physical data models
|
|
Structure that makes the search for particular database records efficient
|
Access path
|
|
Example of an access path
Allows direct access to data using an index term or a keyword |
Index
|
|
Description of a database
|
Database schema
|
|
Displays selected aspects of schema
|
Schema diagram
|
|
Each object in the schema
|
Schema construct
|
|
Data in database at a particular moment in time
|
Database state or snapshot
|
|
Specify database schema to the DBMS
|
Define a new database
|
|
Populated or loaded with the initial data
|
Initial state
|
|
Satisfies the structure and constraints specified in the schema
|
Valid state
|
|
Changes applied to schema as application requirements change
|
Schema evolution
|
|
Describes physical storage structure of the database
|
Internal level
|
|
Describes structure of the whole database for a community of users
|
Conceptual level
|
|
Describes part of the database that a particular user group is interested in
|
External or view level
|
|
types of data independence
|
logical and physical
|
|
Capacity to change the schema at one level of a database system
Without having to change the schema at the next higher level |
Data Independence
|
|
Defines both schemas (language)
|
Data definition language (DDL)
|
|
Specifies the internal schema (language)
|
Storage definition language (SDL)
|
|
Specifies user views/mappings to conceptual schema (language)
|
View definition language (VDL)
|
|
Allows retrieval, insertion, deletion, modification (language)
|
Data manipulation language (DML)
|
|
Can be used on its own to specify complex database operations concisely
•Set-at-a-time or set-oriented (language) |
High-level or nonprocedural DML
|
|
Must be embedded in a general-purpose programming language
•Record-at-a-time (language) |
Low-level or procedural DML
|
|
Load existing data files
|
loading
|
|
Creates a backup copy of the database
|
backup
|