Chapter 1 - 5 Revision Flashcards
List all the levels in which data quality can be examined.
Data Accuracy
Data relevancy
Data Completeness
Data Timeliness
Data Uniqueness
Data Unambiguity
Define Data governance.
Organizational strategy to ensure data quality.
What is the purpose of data governance?
Manage data availability, usability, quality, integrity, and security.
List the advantages of DBMS.
Improved data sharing.
Better data integration
Minimized data inconsistency
Improved data access
Why is database design important?
Poorly designed database generates errors that lead to bad decisions and can lead to the failure of an organization.
List the problems with File System Data Management.
Long development times.
Extensive programming.
Lack of security
Limited data sharing
Difficulty in getting quick answers
Explain data redundancy in detail.
data redundancy leads to data inconsistency.
data redundancy also leads to data anamolies.
There are 3 types of data anomalies, namely:
update anamoly - occurs when an inconsistency is introduced as changes are made to existing records.
insert anomaly - occurs when an inconsistency is introduced when entering new records.
deletion anomaly - occurs when an inconsistency is introduced when deleting
records.
List the functions of DBMS.
Data dictionary management - defines data elements and relationships.
Data storage management - stores data.
Data transformation and presentation - finds data based on your request
Security management - protects data within database.
Backup and recovery management - provides backup and data recovery procedures.
Data integrity management - enforces integrity rules.
List the importance of data models.
they facilitate interaction among the designer, programmer and user.
they are simple representations of complex real-world data structures.
they organize data for different users
What are business rules?
Clear policies that define actions within an organization.
List the properties of business rules.
Business rules must be:
rendered in writing.
kept up-to-date.
easy to understand.
sometimes be external to the organization.
List the sources of business rules.
Company managers
Policymakers
Department managers
Written documentation
Direct interviews with end-users
What is an advantage of the RDBMS?
It can hide the complexities of the relational model from the user.
What is big data?
It is managing large web data for business insights, performance, and scalability at a good cost.
List the properties of a relation.
A table is a two-dimensional structure with rows and columns.
Each row represents a single entity occurrence, and all rows must be unique.
Each column represents an attribute with a distinct name.
Each cell contains a single atomic value.
All values in a column must be of the same data type.
Each column has a defined range of values, called the domain.
The order of the rows and columns doesn’t matter.
Each table must have a unique identifier for each row.
