Android本地SQLite无外键数据库替代ERD的文档编制方案咨询

Great question! Since your SQLite tables are independent (no foreign keys linking them), ERDs might feel incomplete or fail to capture the real-world context of how your Android app interacts with these tables. Here are some practical, targeted documentation methods to fill that gap:

1. Table-by-Table Detailed Reference #

Create a dedicated section for each table that goes beyond just column definitions. Use a Markdown table for clarity, and add context that matters for your app:

Add extra details below the table:

• Indexes: last_login has an index to speed up queries for recent user activity.
• Common Queries:

  SELECT full_name, last_login FROM user_profiles WHERE last_login > datetime('now', '-30 days');
  

  Used to generate a list of users active in the past month.

2. Business Logic-to-Table Mapping #

Since there are no database-level foreign keys, the relationships between tables exist in your app's code. Document these explicitly by mapping core business flows to the tables they use:

• Checkout Flow:
  1. Read selected items from cart_items
  2. Insert order header into orders
  3. Insert individual order lines into order_items
  4. Update stock counts in product_inventory
• Key Code Association: In the checkout ViewModel, orders.order_id is used to link all order_items to a single purchase (no foreign key, but enforced via app logic).

3. Data Flow Diagrams (DFDs) #

Sketch simple, text-based or visual diagrams that show how data moves between your app's components and database tables. For example:

User submits profile edit → ViewModel validates input → Writes updated data to user_profiles → Reads fresh data from table → Updates UI with new profile info

This helps readers understand each table's role in the app's user journey, not just its structure.

4. Schema Migration History #

SQLite requires manual schema migrations for version updates—documenting this is critical for maintainability:

• v1.0: Initial schema with user_profiles and product_inventory tables
• v1.1: Added phone_number column to user_profiles

  ALTER TABLE user_profiles ADD COLUMN phone_number TEXT;
  

• v1.2: Created cart_items table to support shopping cart functionality

Note any edge cases, like how you handled existing data when adding new columns.

5. Sample Data Snippets #

Include realistic sample data for each table to make abstract column definitions concrete:

-- Sample data for product_inventory
INSERT INTO product_inventory (product_id, name, price, stock_count)
VALUES (1, 'Wireless Headphones', 99.99, 45),
       (2, 'Phone Case', 19.99, 120);

This helps new developers or stakeholders quickly grasp what kind of data each table holds.

Combining these methods will give you a comprehensive database document that focuses on how your app actually uses the tables, rather than just their isolated structures.

内容的提问来源于stack exchange，提问作者Eric Marcelino