Module 4.1
Database design and concepts
Relational Databases
Select: when we choose what entities we want to record and what data about that entity
is important
Structure: what tables we need and what the relationship between the tables are
Normalization
Formal rules applied in a specific order to ensure databases are designed correctly
Series of steps that need to be followed
Third Normal Form: no redundant data: databases we work with
Unprocessed data – data where no entities, attributes or relationships have been identified
Basic Database design
Faster, easier, more accurate, more reliable, more flexible and lest costs
1. Selecting the data
What data you need and where the data can be obtained from
Existing documents: take note of every distinct piece of information
and that it has an appropriate heading
Existing workflows: order in which things get done. Might not appear in
other documentation. Identify data needed to monitor processors
Business plan: document which outlines the strategies to used to ensure
that your business is a success.
2. Structuring data
Place data of each entity in separate tables, determine relationship and link
tables with foreign key
Insert Anomaly Prevents user from capturing data
Delete Anomaly Deleting one piece of data result in the removal of unrelated data
Update When data changes it has to be altered in multiple records
Anomaly
Increases efficiency
Minimizes wastage of storage and memory
Eliminates errors
Data maintenance – keep data current (adding, deleting, and updating records)
Database design and concepts
Relational Databases
Select: when we choose what entities we want to record and what data about that entity
is important
Structure: what tables we need and what the relationship between the tables are
Normalization
Formal rules applied in a specific order to ensure databases are designed correctly
Series of steps that need to be followed
Third Normal Form: no redundant data: databases we work with
Unprocessed data – data where no entities, attributes or relationships have been identified
Basic Database design
Faster, easier, more accurate, more reliable, more flexible and lest costs
1. Selecting the data
What data you need and where the data can be obtained from
Existing documents: take note of every distinct piece of information
and that it has an appropriate heading
Existing workflows: order in which things get done. Might not appear in
other documentation. Identify data needed to monitor processors
Business plan: document which outlines the strategies to used to ensure
that your business is a success.
2. Structuring data
Place data of each entity in separate tables, determine relationship and link
tables with foreign key
Insert Anomaly Prevents user from capturing data
Delete Anomaly Deleting one piece of data result in the removal of unrelated data
Update When data changes it has to be altered in multiple records
Anomaly
Increases efficiency
Minimizes wastage of storage and memory
Eliminates errors
Data maintenance – keep data current (adding, deleting, and updating records)
