Lesson 6: Server-Side Development, CRUD, and Database Integration

The server side handles the parts of a web application that should not depend only on the browser. Its common responsibilities include:

• routing requests,
• validating submitted data,
• applying business rules,
• managing authentication and sessions,
• reading and writing data,
• and sending responses.

For example, when a user submits a room reservation request, the server may need to:

• check if the room exists,
• verify that the date is valid,
• confirm that the room is still available,
• save the reservation,
• and return a success or error response.

This work should not be trusted to front-end code alone because browser code can be changed by the user.

A large number of web applications are CRUD systems. CRUD stands for:

• Create
• Read
• Update
• Delete

Examples in Philippine contexts:

• Create a barangay complaint record
• Read a list of permit requests
• Update a product price in an online catalog
• Delete an expired announcement

A useful way to model features is by asking:

• what entities exist,
• what actions users can perform,
• and what permissions apply.

Entities might include:

• users,
• posts,
• products,
• reservations,
• grades,
• departments,
• or documents.

Once you identify the entities, CRUD becomes much easier to design.