PART IV · BACKEND

Business Logic

The rules and decisions that determine how a business operation should work.

01

What is it?

Business logic represents the rules that turn business requirements into system behavior.

It determines what should happen when users or systems perform business operations.

Simple Definition: Business logic is the system's business decision-making logic.

02

Think of it like...

Think of a company's operating rules.

The backend receives an action.

Business logic decides whether it is allowed and what should happen next.

03

What does it do?

Apply Business Rules
Calculate Values
Check Conditions
Control Workflow
Make Decisions
Coordinate Operations
04

Where is it used?

Business logic is used in:

Order Management Pricing Payments Approvals Inventory Settlement
05

Example

Create Order

Scenario: Create Order

Rules:

  • Customer must be active.
  • Quantity must be greater than 0.
  • Available credit must be sufficient.

Flow

Request
Business Rules
Approve / Reject
Save Result
06

How it connects

Route
Validation
Business Logic
Repository / Service
Database
07

Do Not Confuse

Validation

Checks whether input has acceptable structure or values.

Business Logic

Applies business decisions and rules.

08

Topic Glossary

ENGLISH TERM中文SIMPLE ENGLISH中文小白理解
Business Logic业务逻辑Rules that determine how business operations work.决定系统业务流程应该如何处理的一组规则。
Business Rule业务规则One rule defining allowed or required behavior.规定业务在什么条件下可以或不可以执行的一条规则。
Workflow工作流A sequence of business steps.一个业务从开始到结束需要经过的一系列步骤。
Condition条件A rule used to decide what happens next.用来判断后续应该执行什么操作的条件。
Calculation计算逻辑Logic used to calculate business values.用来计算价格、金额、数量等业务结果的规则。
Decision决策A result chosen based on rules and conditions.系统根据业务条件判断后得出的处理结果。
09

What to Remember

Business logic represents business rules in software.

It sits between request handling and data operations.

Good business logic should be separated from transport details when practical.

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