Cloud Firestore ile verileri sipariş edin ve sınırlayın

Cloud Firestore, bir koleksiyondan hangi belgeleri almak istediğinizi belirtmek için güçlü sorgu işlevi sağlar. Bu sorgular, Get Data içinde açıklandığı gibi get() veya addSnapshotListener() ile de kullanılabilir.

Verileri sipariş et ve sınırla

Varsayılan olarak bir sorgu, sorguyu karşılayan tüm belgeleri belge kimliğine göre artan sırada alır. orderBy() kullanarak verileriniz için sıralama düzenini belirleyebilir ve limit() öğesini kullanarak alınan belge sayısını sınırlayabilirsiniz.

Örneğin, ilk 3 şehri aşağıdakilerle alfabetik olarak sorgulayabilirsiniz:

Web version 9

import { query, orderBy, limit } from "firebase/firestore";  

const q = query(citiesRef, orderBy("name"), limit(3));
order_and_limit.js

Web version 8

citiesRef.orderBy("name").limit(3);
test.firestore.js
Süratli
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
citiesRef.order(by: "name").limit(to: 3)
ViewController.swift
Amaç-C
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
[[citiesRef queryOrderedByField:@"name"] queryLimitedTo:3];
ViewController.m

Java

citiesRef.orderBy("name").limit(3);
DocSnippets.java

Kotlin+KTX

citiesRef.orderBy("name").limit(3)
DocSnippets.kt

Dart

final citiesRef = db.collection("cities");
citiesRef.orderBy("name").limit(3);
firestore.dart
Java
Query query = cities.orderBy("name").limit(3);
Query query = cities.orderBy("name").limitToLast(3);
QueryDataSnippets.java
piton
cities_ref = db.collection("cities")
query = cities_ref.order_by("name").limit_to_last(2)
results = query.get()
snippets.py

Python

cities_ref = db.collection("cities")
query = cities_ref.order_by("name").limit_to_last(2)
results = await query.get()
snippets.py
C++
cities_ref.OrderBy("name").Limit(3);
snippets.cpp
Node.js
const firstThreeRes = await citiesRef.orderBy('name').limit(3).get();
index.js
Gitmek
query := cities.OrderBy("name", firestore.Asc).Limit(3)
query := cities.OrderBy("name", firestore.Asc).LimitToLast(3)
query.go
PHP
$query = $citiesRef->orderBy('name')->limit(3);
query_order_limit.php
Birlik
Query query = citiesRef.OrderBy("Name").Limit(3);
C#
Query query = citiesRef.OrderBy("Name").Limit(3);
Program.cs
yakut
query = cities_ref.order("name").limit(3)
order_limit_data.rb

Son 3 şehri almak için azalan düzende de sıralayabilirsiniz:

Web version 9

import { query, orderBy, limit } from "firebase/firestore";  

const q = query(citiesRef, orderBy("name", "desc"), limit(3));
order_and_limit_desc.js

Web version 8

citiesRef.orderBy("name", "desc").limit(3);
test.firestore.js
Süratli
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
citiesRef.order(by: "name", descending: true).limit(to: 3)
ViewController.swift
Amaç-C
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
[[citiesRef queryOrderedByField:@"name" descending:YES] queryLimitedTo:3];
ViewController.m

Java

citiesRef.orderBy("name", Direction.DESCENDING).limit(3);
DocSnippets.java

Kotlin+KTX

citiesRef.orderBy("name", Query.Direction.DESCENDING).limit(3)
DocSnippets.kt

Dart

final citiesRef = db.collection("cities");
citiesRef.orderBy("name", descending: true).limit(3);
firestore.dart
Java
Query query = cities.orderBy("name", Direction.DESCENDING).limit(3);
QueryDataSnippets.java
piton
cities_ref = db.collection(u'cities')
query = cities_ref.order_by(
    u'name', direction=firestore.Query.DESCENDING).limit(3)
results = query.stream()
snippets.py

Python

cities_ref = db.collection("cities")
query = cities_ref.order_by("name", direction=firestore.Query.DESCENDING).limit(3)
results = query.stream()
snippets.py
C++
cities_ref.OrderBy("name", Query::Direction::kDescending).Limit(3);
snippets.cpp
Node.js
const lastThreeRes = await citiesRef.orderBy('name', 'desc').limit(3).get();
index.js
Gitmek
query := cities.OrderBy("name", firestore.Desc).Limit(3)
query.go
PHP
$query = $citiesRef->orderBy('name', 'DESC')->limit(3);
query_order_desc_limit.php
Birlik
Query query = citiesRef.OrderByDescending("Name").Limit(3);
C#
Query query = citiesRef.OrderByDescending("Name").Limit(3);
Program.cs
yakut
query = cities_ref.order("name", "desc").limit(3)
order_limit_data.rb

Ayrıca birden fazla alana göre sipariş verebilirsiniz. Örneğin, eyalete göre ve her eyalette nüfusa göre azalan sırayla sıralamak istiyorsanız:

Web version 9

import { query, orderBy } from "firebase/firestore";  

const q = query(citiesRef, orderBy("state"), orderBy("population", "desc"));
order_multiple.js

Web version 8

citiesRef.orderBy("state").orderBy("population", "desc");
test.firestore.js
Süratli
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
citiesRef
    .order(by: "state")
    .order(by: "population", descending: true)
ViewController.swift
Amaç-C
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
[[citiesRef queryOrderedByField:@"state"] queryOrderedByField:@"population" descending:YES];
ViewController.m

Java

citiesRef.orderBy("state").orderBy("population", Direction.DESCENDING);
DocSnippets.java

Kotlin+KTX

citiesRef.orderBy("state").orderBy("population", Query.Direction.DESCENDING)
DocSnippets.kt

Dart

final citiesRef = db.collection("cities");
citiesRef.orderBy("state").orderBy("population", descending: true);
firestore.dart
Java
Query query = cities.orderBy("state").orderBy("population", Direction.DESCENDING);
QueryDataSnippets.java
piton
cities_ref = db.collection(u'cities')
cities_ref.order_by(u'state').order_by(
    u'population', direction=firestore.Query.DESCENDING)
snippets.py

Python

cities_ref = db.collection("cities")
cities_ref.order_by("state").order_by(
    "population", direction=firestore.Query.DESCENDING
)
snippets.py
C++
cities_ref.OrderBy("state").OrderBy("name", Query::Direction::kDescending);
snippets.cpp
Node.js
const byStateByPopRes = await citiesRef.orderBy('state').orderBy('population', 'desc').get();
index.js
Gitmek
query := client.Collection("cities").OrderBy("state", firestore.Asc).OrderBy("population", firestore.Desc)
query.go
PHP
$query = $citiesRef->orderBy('state')->orderBy('population', 'DESC');
query_order_multi.php
Birlik
Query query = citiesRef.OrderBy("State").OrderByDescending("Population");
C#
Query query = citiesRef.OrderBy("State").OrderByDescending("Population");
Program.cs
yakut
query = cities_ref.order("state").order("population", "desc")
order_limit_data.rb

where() filtrelerini orderBy() ve limit() ile birleştirebilirsiniz. Aşağıdaki örnekte, sorgular bir popülasyon eşiği tanımlar, popülasyona göre artan düzende sıralar ve yalnızca eşiği aşan ilk birkaç sonucu döndürür:

Web version 9

import { query, where, orderBy, limit } from "firebase/firestore";  

const q = query(citiesRef, where("population", ">", 100000), orderBy("population"), limit(2));
filter_and_order.js

Web version 8

citiesRef.where("population", ">", 100000).orderBy("population").limit(2);
test.firestore.js
Süratli
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
citiesRef
    .whereField("population", isGreaterThan: 100000)
    .order(by: "population")
    .limit(to: 2)
ViewController.swift
Amaç-C
Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
[[[citiesRef queryWhereField:@"population" isGreaterThan:@100000]
    queryOrderedByField:@"population"]
    queryLimitedTo:2];
ViewController.m

Java

citiesRef.whereGreaterThan("population", 100000).orderBy("population").limit(2);
DocSnippets.java

Kotlin+KTX

citiesRef.whereGreaterThan("population", 100000).orderBy("population").limit(2)
DocSnippets.kt

Dart

final citiesRef = db.collection("cities");
citiesRef
    .where("population", isGreaterThan: 100000)
    .orderBy("population")
    .limit(2);
firestore.dart
Java
Query query = cities.whereGreaterThan("population", 2500000L).orderBy("population").limit(2);
QueryDataSnippets.java
piton
cities_ref = db.collection(u'cities')
query = cities_ref.where(
    u'population', u'>', 2500000).order_by(u'population').limit(2)
results = query.stream()
snippets.py

Python

cities_ref = db.collection("cities")
query = cities_ref.where("population", ">", 2500000).order_by("population").limit(2)
results = query.stream()
snippets.py
C++
cities_ref.WhereGreaterThan("population", FieldValue::Integer(100000))
    .OrderBy("population")
    .Limit(2);
snippets.cpp
Node.js
const biggestRes = await citiesRef.where('population', '>', 2500000)
  .orderBy('population').limit(2).get();
index.js
Gitmek
query := cities.Where("population", ">", 2500000).OrderBy("population", firestore.Desc).Limit(2)
query.go
PHP
$query = $citiesRef
    ->where('population', '>', 2500000)
    ->orderBy('population')
    ->limit(2);
query_order_limit_field_valid.php
Birlik
Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Population")
    .Limit(2);
C#
Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Population")
    .Limit(2);
Program.cs
yakut
query = cities_ref.where("population", ">", 2_500_000).order("population").limit(2)
order_limit_data.rb

Ancak, aralık karşılaştırmalı bir filtreniz varsa ( < , <= , > , >= ), ilk siparişiniz aynı alanda olmalıdır, aşağıdaki orderBy() sınırlamaları listesine bakın.

sınırlamalar

orderBy() yan tümceleri için aşağıdaki kısıtlamalara dikkat edin:

  • orderBy() yan tümcesi ayrıca verilen alanların varlığını filtreler. Sonuç kümesi, verilen alanları içermeyen belgeleri içermeyecektir.

  • Aralık karşılaştırmalı bir filtre eklerseniz ( < , <= , > , >= ), ilk siparişiniz aynı alanda olmalıdır:

    Geçerli : Aynı alanda aralık filtresi ve orderBy

    Web version 9

    import { query, where, orderBy } from "firebase/firestore";  

const q = query(citiesRef, where("population", ">", 100000), orderBy("population"));
    valid_filter_and_order.js

    Web version 8

    citiesRef.where("population", ">", 100000).orderBy("population");
    test.firestore.js
    Süratli
    Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
    citiesRef
    .whereField("population", isGreaterThan: 100000)
    .order(by: "population")
    ViewController.swift
    Amaç-C
    Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
    [[citiesRef queryWhereField:@"population" isGreaterThan:@100000]
    queryOrderedByField:@"population"];
    ViewController.m

    Java

    citiesRef.whereGreaterThan("population", 100000).orderBy("population");
    DocSnippets.java

    Kotlin+KTX

    citiesRef.whereGreaterThan("population", 100000).orderBy("population")
    DocSnippets.kt

    Dart

    final citiesRef = db.collection("cities");
citiesRef.where("population", isGreaterThan: 100000).orderBy("population");
    firestore.dart
    Java
    Query query = cities.whereGreaterThan("population", 2500000L).orderBy("population");
    QueryDataSnippets.java
    piton
    cities_ref = db.collection(u'cities')
query = cities_ref.where(
    u'population', u'>', 2500000).order_by(u'population')
results = query.stream()
    snippets.py

    Python

    cities_ref = db.collection("cities")
query = cities_ref.where("population", ">", 2500000).order_by("population")
results = query.stream()
    snippets.py
    Node.js
    citiesRef.where('population', '>', 2500000).orderBy('population');
    index.js
    Gitmek
    query := cities.Where("population", ">", 2500000).OrderBy("population", firestore.Asc)
    query.go
    PHP
    $query = $citiesRef
    ->where('population', '>', 2500000)
    ->orderBy('population');
    query_order_with_filter.php
    Birlik
    Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Population");
    C#
    Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Population");
    Program.cs
    yakut
    query = cities_ref.where("population", ">", 2_500_000).order("population")
    order_limit_data.rb

    Geçersiz : Aralık filtresi ve farklı alanlarda ilk orderBy

    Web version 9

    import { query, where, orderBy } from "firebase/firestore";  

const q = query(citiesRef, where("population", ">", 100000), orderBy("country"));
    invalid_filter_and_order.js

    Web version 8

    citiesRef.where("population", ">", 100000).orderBy("country");
    test.firestore.js
    Süratli
    Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
    citiesRef
    .whereField("population", isGreaterThan: 100000)
    .order(by: "country")
    ViewController.swift
    Amaç-C
    Not: Bu ürün, watchOS ve App Clip hedeflerinde mevcut değildir.
    [[citiesRef queryWhereField:@"population" isGreaterThan:@100000] queryOrderedByField:@"country"];
    ViewController.m

    Java

    citiesRef.whereGreaterThan("population", 100000).orderBy("country");
    DocSnippets.java

    Kotlin+KTX

    citiesRef.whereGreaterThan("population", 100000).orderBy("country")
    DocSnippets.kt

    Dart

    final citiesRef = db.collection("cities");
citiesRef.where("population", isGreaterThan: 100000).orderBy("country");
    firestore.dart
    Java
    Query query = cities.whereGreaterThan("population", 2500000L).orderBy("country");
    QueryDataSnippets.java
    piton
    cities_ref = db.collection(u'cities')
query = cities_ref.where(u'population', u'>', 2500000).order_by(u'country')
results = query.stream()
    snippets.py

    Python

    cities_ref = db.collection("cities")
query = cities_ref.where("population", ">", 2500000).order_by("country")
results = query.stream()
    snippets.py
    C++
    // BAD EXAMPLE -- will crash the program:
cities_ref.WhereGreaterThan("population", FieldValue::Integer(100000))
    .OrderBy("country");
    snippets.cpp
    Node.js
    citiesRef.where('population', '>', 2500000).orderBy('country');
    index.js
    Gitmek
    // Note: This is an invalid query. It violates the constraint that range
// and order by are required to be on the same field.
query := cities.Where("population", ">", 2500000).OrderBy("country", firestore.Asc)
    query.go
    PHP
    $invalidRangeQuery = $citiesRef
    ->where('population', '>', 2500000)
    ->orderBy('country');
    query_order_field_invalid.php
    Birlik
    Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Country");
    C#
    Query query = citiesRef
    .WhereGreaterThan("Population", 2500000)
    .OrderBy("Country");
    Program.cs
    yakut
    query = cities_ref.where("population", ">", 2_500_000).order("country")
    order_limit_data.rb
  • Sorgunuzu eşitlikte ( = ) veya yan tümcede in herhangi bir alana göre sıralayamazsınız.