Data Storage Methods Flashcards
Building blocks of information
Data
Produced by processing data; reveals the meaning of data
Information
Shared, integrated computer structure
Database
Two types of data
End user data
Metadata
Main data
End user data
Data about data
Metadata
Manages Database Structure
Controls access to data
Contains query language
Database Management System (DBMS)
Good at storage and easy to access
Database
Good at calculation
Excel
Has storage capacity limitation
Excel
Better when parts of the data needs to be updated
DB
Importance of DBMS (5)
Makes data management more efficient and effective
Query language allows quick answers to ad hoc queries
Provides better access to more and better-managed data
Promotes integrated view of organization’s operations
Reduces the probability of inconsistent data
Importance of good design (2)
Poor design results in unwanted data redundancy
Poor design generates errors leading to bad decisions
Focus on principles and concepts of database design; importance of logical design
Practical approach
Raw facts
Data
Group of characters with specific meaning
Field/Attribute (column header)
Logically connected fields that describe a person, place or thing
Record/Row/Tuple
Collection of related records
Table
Entity/relation
Table
Field/attribute
Column
Record/instance
Row
Stores data in several tables that are connected to each other
Relational Database Model
Relational Database Model (3)
Perceived by user as a collection of tables for data storage
Tables are a series of row/column intersections
Tables related by sharing common entity characteristic(s)
A column or several columns in the table, which uniquely identify each record in that table; there must be one and only one in each table
Primary key
A column or several columns in a table, which are in then a PK in some other table; there may be more than one or none in a table
Foreign key
Primary key placed in another table is a
Foreign key
Database design requirements (3)
Store all data
Avoid redundant storage of data
Preserve the relationships between data
How do we minimize data redundancy?
Primary Key
How do we preserve relationships
Foreign Keys
