Data, SQL, and system thinking
Opening notes
Welcome the viewer. Explain that this is one lesson in the eight-part Job-Ready Software Engineering series. Set up the outcome before beginning.
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Data, SQL, and system thinking
Follow the data
Understand what the feature must remember
Speaker notes
Every feature has data behind it. Understanding data helps you debug, test, and design better software.
From story to data
- Who owns it?
- Which company and role?
- Current status?
- Next action?
- Due date?
Speaker notes
Before writing SQL, ask what the system needs to remember and what rules should always be true.
Model the relationships
- Primary key identifies a row
- Foreign key connects rows
- Constraints protect valid data
- One user can have many applications
Speaker notes
The model encodes decisions. It is not decoration.
SQL answers business questions
- Filter rows
- Join related data
- Group and count
- Order useful results
Speaker notes
Read queries in plain language. The important skill is connecting a business question to a query.
Edge cases are product behavior
- Missing company
- Duplicate application
- Unknown status
- Time zone boundary
- Deleted user
- Empty search
Speaker notes
Every edge case is a chance for a bug or an explicit decision.
Demo: investigate a reporting defect
The dashboard says there are no active applications.
Speaker notes
Show a query that uses the wrong status or a join that hides rows. Fix it and explain why the original result was misleading.
Pause: ask a data question
- Write one business question
- Write the SQL needed to answer it
- Explain what the result means
Speaker notes
Examples: which companies have more than one active application? How long do applications stay in interview status?
Your artifact
- Small schema diagram
- Three useful queries
- One documented trade-off
Speaker notes
This is enough to show system thinking without pretending to be a database specialist.
Make the artifact.
Publish your work, then continue to the next lesson.
Closing notes
Repeat the artifact viewers should create. Invite them to subscribe and join the future live cohort waitlist.