CloudBase Document Database WeChat Mini Program SDK

Activation Contract

Use this first when

• A WeChat Mini Program must access CloudBase document database through wx.cloud.database().
• The request mentions Mini Program collection CRUD, pagination, aggregation, or geolocation queries.

Read before writing code if

• The task is Mini Program database work but you still need to separate it from Web SDK, cloud functions, or SQL tasks.
• The request depends on built-in user identity, _openid, or Mini Program-side permissions.

Then also read

• Mini Program project rules and CloudBase integration -> ../miniprogram-development/SKILL.md
• Mini Program auth and identity flow -> ../auth-wechat/SKILL.md
• Browser-side document database code -> ../no-sql-web-sdk/SKILL.md

Do NOT use for

• Browser/Web code using @cloudbase/js-sdk.
• Server-side or cloud-function database access.
• MySQL / relational database work.

Common mistakes / gotchas

• Copying Web SDK code into Mini Program pages.
• Manually writing _openid during create or update operations.
• Assuming built-in Mini Program identity means security rules can be ignored.
• Mixing collection CRUD and backend-wide admin workflows in the same client path.

Minimal checklist

• Confirm the caller is a Mini Program page/component or Mini Program-side logic.
• Initialize wx.cloud correctly before database calls.
• Verify whether the collection rules rely on auth.openid / _openid.
• Read the specific companion reference file for the operation you need.

Overview

This skill covers Mini Program-side document database access through wx.cloud.database().

Use it for:

• collection CRUD in Mini Program pages
• query composition and pagination
• aggregation
• geolocation queries

Mini Program CloudBase access comes with built-in identity, but database operations are still constrained by collection permissions and security rules.

Canonical initialization

const db = wx.cloud.database();
const _ = db.command;

To target a specific environment:

const db = wx.cloud.database({
  env: "test"
});

Important notes:

• Users are authenticated through the Mini Program CloudBase context.
• In cloud functions, caller identity is available through wxContext.OPENID.
• In client-side collection rules, ownership checks usually use auth.openid / doc._openid.

Quick routing

• CRUD -> ./crud-operations.md
• Complex queries -> ./complex-queries.md
• Pagination -> ./pagination.md
• Aggregation -> ./aggregation.md
• Geolocation -> ./geolocation.md
• Security rules -> ./security-rules.md

Working rules for a coding agent

1. Keep Mini Program code Mini Program-native

   • Use wx.cloud.database().
   • Do not substitute browser SDK initialization patterns.

2. Respect ownership fields

   • _openid is system-managed for SDK writes.
   • Never set or override _openid manually in .add(), .set(), or .update() payloads.

3. Remember that security rules validate requests

   • If a rule requires ownership conditions, the query shape must match that rule model.
   • Permission errors usually mean the rule/query relationship is wrong, not only that the user is logged out.

4. Route admin-style operations to backend flows

   • If the task needs privileged global access, use backend tools or functions instead of exposing that path directly in Mini Program client code.

Quick examples

Basic collection access

const todos = db.collection("todos");
const result = await todos.where({ completed: false }).get();

Document reference

const todo = db.collection("todos").doc("todo-id");
const result = await todo.get();

Best practices

1. Create clear collection naming conventions.
2. Use typed wrappers or model helpers in app code where possible.
3. Design rules around real ownership and sharing patterns.
4. Use pagination instead of large unbounded reads.
5. Keep admin/operations logic in backend code, not Mini Program direct access.