Union

Açıklama

Başka bir işlem hattındaki belgeleri mevcut işlem hattındaki belgelerle birleştirir.

Söz dizimi

Node.js

const results = await db.pipeline()
  .collection("cities/SF/restaurants")
  .union(db.pipeline().collection("cities/NYC/restaurants"))
  .execute();

Müşteri örnekleri

Node.js
  const results = await db.pipeline()
    .collection("cities/SF/restaurants")
    .where(eq("type", "chinese"))
    .union(db.pipeline()
      .collection("cities/NYC/restaurants")
      .where(eq("type", "italian")))
    .where(gte("rating", 4.5))
    .execute();

Web

const results = await execute(db.pipeline()
  .collection("cities/SF/restaurants")
  .where(field("type").equal("Chinese"))
  .union(db.pipeline()
    .collection("cities/NY/restaurants")
    .where(field("type").equal("Italian")))
  .where(field("rating").greaterThanOrEqual(4.5))
  .sort(field("__name__").descending())
);
test.firestore.js
Swift
let results = try await db.pipeline()
  .collection("cities/SF/restaurants")
  .where(Field("type").equal("Chinese"))
  .union(with: db.pipeline()
    .collection("cities/NY/restaurants")
    .where(Field("type").equal("Italian")))
  .where(Field("rating").greaterThanOrEqual(4.5))
  .sort([Field("__name__").descending()])
  .execute()
PipelineSnippets.swift

Kotlin

val results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute()
DocSnippets.kt

Java

Task<Pipeline.Snapshot> results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

results = (
    client.pipeline()
    .collection("cities/SF/restaurants")
    .where(Field.of("type").equal("Chinese"))
    .union(
        client.pipeline()
        .collection("cities/NY/restaurants")
        .where(Field.of("type").equal("Italian"))
    )
    .where(Field.of("rating").greater_than_or_equal(4.5))
    .sort(Field.of("__name__").descending())
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot results =
    firestore
        .pipeline()
        .collection("cities/SF/restaurants")
        .where(field("type").equal("Chinese"))
        .union(
            firestore
                .pipeline()
                .collection("cities/NY/restaurants")
                .where(field("type").equal("Italian")))
        .where(field("rating").greaterThanOrEqual(4.5))
        .sort(descending(field("__name__")))
        .execute()
        .get();
PipelineSnippets.java

Davranış

Bu aşamada birden fazla işlem hattı paralel olarak çalıştırılır ve sonuçlar birleştirilir.

Sonuçların Belirlenimci Olmayan Sırası

İki işlem hattı arasında sonuçların birleştirilme sırası deterministik değildir. Algılanan düzen kararsızdır ve güvenilmemelidir. Sabit bir sıra gerekirse aşağıdaki sort aşaması eklenebilir.

Node.js
  const results = await db.pipeline()
    .collection("cities/SF/restaurants")
    .where(eq("type", "chinese"))
    .union(db.pipeline()
      .collection("cities/NYC/restaurants")
      .where(eq("type", "italian")))
    .where(gte("rating", 4.5))
    .sort(Field.of("__name__"))
    .execute();

Kotlin

val results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute()
DocSnippets.kt

Java

Task<Pipeline.Snapshot> results = db.pipeline()
    .collection("cities/SF/restaurants")
    .where(field("type").equal("Chinese"))
    .union(db.pipeline()
        .collection("cities/NY/restaurants")
        .where(field("type").equal("Italian")))
    .where(field("rating").greaterThanOrEqual(4.5))
    .sort(field("__name__").descending())
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

results = (
    client.pipeline()
    .collection("cities/SF/restaurants")
    .where(Field.of("type").equal("Chinese"))
    .union(
        client.pipeline()
        .collection("cities/NY/restaurants")
        .where(Field.of("type").equal("Italian"))
    )
    .where(Field.of("rating").greater_than_or_equal(4.5))
    .sort(Field.of("__name__").descending())
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot results =
    firestore
        .pipeline()
        .collection("cities/SF/restaurants")
        .where(field("type").equal("Chinese"))
        .union(
            firestore
                .pipeline()
                .collection("cities/NY/restaurants")
                .where(field("type").equal("Italian")))
        .where(field("rating").greaterThanOrEqual(4.5))
        .sort(descending(field("__name__")))
        .execute()
        .get();
PipelineSnippets.java

Yinelenen Sonuçlar

union aşamasında sonuçlar tekilleştirilmez. Yinelenen sonuçların kaldırılması gerekiyorsa aşağıdaki distinct veya aggregate aşaması eklenebilir.