文件集

說明

傳回指定集合中的所有文件。集合可以巢狀結構。

語法

Node.js

const results = await db.pipeline()
  .collection('/cities/SF/departments')
  .execute();

用戶端範例

Web

const results = await execute(db.pipeline()
  .collection("users/bob/games")
  .sort(field("name").ascending())
  );
test.firestore.js
Swift
let results = try await db.pipeline()
  .collection("users/bob/games")
  .sort([Field("name").ascending()])
  .execute()
PipelineSnippets.swift

Kotlin

val results = db.pipeline()
    .collection("users/bob/games")
    .sort(field("name").ascending())
    .execute()
DocSnippets.kt

Java

Task<Pipeline.Snapshot> results = db.pipeline()
    .collection("users/bob/games")
    .sort(field("name").ascending())
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

results = (
    client.pipeline()
    .collection("users/bob/games")
    .sort(Field.of("name").ascending())
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot results =
    firestore
        .pipeline()
        .collection("users/bob/games")
        .sort(ascending(field("name")))
        .execute()
        .get();
PipelineSnippets.java

行為

如要使用 collection 階段，該階段必須是管道中的第一個階段。

從 collection 階段傳回的文件順序不穩定，不應做為依據。後續的排序階段可用於取得確定性排序。

舉例來說，下列文件：

Node.js

await db.collection('cities').doc('SF').set({name: 'San Francsico', state: 'California'});
await db.collection('cities').doc('NYC').set({name: 'New York City', state: 'New York'});
await db.collection('cities').doc('CHI').set({name: 'Chicago', state: 'Illinois'});
await db.collection('states').doc('CA').set({name: 'California'});

collection 階段可用於擷取 cities 集合中的所有城市，然後依名稱遞增排序。

Node.js

const results = await db.pipeline()
  .collection('/cities')
  .sort(field('name').ascending())
  .execute();

這項查詢會產生下列文件：

  {name: 'Chicago', state: 'Illinois'}
  {name: 'New York City', state: 'New York'}
  {name: 'San Francisco', state: 'California'}

子集合

您也可以提供階段的完整路徑，藉此使用 collection 階段指定特定父項下的集合。

舉例來說，下列文件：

Node.js

await db.collection('cities/SF/departments').doc('building').set({name: 'SF Building Deparment', employees: 750});
await db.collection('cities/NY/departments').doc('building').set({name: 'NY Building Deparment', employees: 1000});
await db.collection('cities/CHI/departments').doc('building').set({name: 'CHI Building Deparment', employees: 900});
await db.collection('cities/NY/departments').doc('finance').set({name: 'NY Finance Deparment', employees: 1200});

在本例中，我們只想要紐約市的部門。

Node.js

const results = await db.pipeline()
  .collection('/cities/NY/departments')
  .sort(field('employees').ascending())
  .execute();

這會傳回完整路徑 cities/NY/departments 下的所有部門。

  {name: 'NY Building Deparment', employees: 1000}
  {name: 'NY Finance Deparment', employees: 1200}