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43 Cards in this Set

  • Front
  • Back
Traditional file approach
no mechanism for tagging, retrieving, or manipulating data; nconvenient: Program-data, dependency, High data redundancy, Low data integrity
Database approach
provides powerful mechanism for managing and manipulating data; data organized as entities
Data redundancy
duplication of data
Data integrity
accuracy of data
Entity
an object about which an organization chooses to collect data, such as: People, Events, Products
Character
smallest piece of data; A single letter or a digit
Field
single piece of information about entity; hold images, sounds, video clips, etc.
Record
collection of related fields
File
collection of related records
Database management system (DBMS)
program used to: Build databases, Populate a database with data, Manipulate data in a database
Query
a message to the database requesting data from specific records and/or fields
Database administrator (DBA)
the person responsible for managing the database; Sets user limits for access to data in the database
Database model
general logical structure; How records stored in the database; How relationships between records are established
Relational Model
consists of tables
Tuple
record (or row)
Attribute
field (or column)
Relation
table of records
Key
a field whose values identify records; Used to retrieve records
Primary key
a field by which records are uniquely identified; Each record in the table must have a unique key value
Composite key
combination of fields that serve as a primary key
Foreign key
a field that is common to two tables; Used to link the tables; This field is a primary key in one table and a foreign key in the other
Object-oriented database model
uses object-oriented approach for the database structure
Join table
composite of tables
One-to-many relationship
one item in a table is linked to many items in the other table
Many-to-many relationship
many items in a table are linked to many items of the other table
Encapsulation
combined storage of data and relevant procedures to process it; Allows object to be “planted” in different data sets
Inheritance
the ability to create a new object by replicating the characteristics of an existing (parent) object
Object-oriented databases (ODBs)
store data objects, not records
Relational operation
creates a temporary subset of a table or tables; create a limited list or a joined table list
Select
a selection of records based on conditions
Project
a selection of certain columns from a table
Join
join data from multiple tables to create a temporary table
Structured Query Language (SQL)
query language of choice for DBMSs; Advantages of SQL: It is an international standard; It is provided with most relational DBMSs; It has easy-to-remember, intuitive commands
Schema:
a plan that describes the structure of the database, including: Names and sizes of fields; Identification of primary keys; Relationships
Data dictionary
a repository of information about the data and its organization; Also called metadata
metadata
the data about the data; including - Source of the data; Tables related to the data; Field and index information; Programs and processes that use the data; Population rules: what is inserted, or updated, and how often
Data modeling
analysis of an organization’s data and identification of the data relationships; A proactive process; Develops a conceptual blueprint of the database
Entity relationship diagram
a graphical representation of all entity relationships; made of - Boxes: identify entities; Lines: indicate relationship between entities; Crossbars: indicate mandatory fields; Circles: indicate optional; Crow’s feet: identify “many”
Data warehouse
a large repository database that supports management decision making; Typically relational; Data is collected from transactional databases
Data mart:
a smaller collection of data focusing on a particular subject or department
Extraction phase
create files from transactional database
Transformation phase
cleanse and modify the data format
Loading phase
transfer files to data warehouse