有没有办法在Firestore中搜索子字符串? [英] Is there a way to search sub string at Firestore?

问题描述

如果在Firestore数据库中有一个名为" California "的字符串，而我想从Android应用程序中搜索为" Cali "，那么Firebase应该会返回加利福尼亚. 我该如何查询?

If there is a String named 'California' at firestore database and i want to search from android app as 'Cali' then the firebase should return me California. How can i do that query?

firestore中有一些功能，例如

There has some function at firestore like,

db.collection("cities").whereEqualTo("name", "Cali")
 db.collection("cities").whereLessThan("name", "Cali")
 db.collection("cities").whereGreaterThanOrEqualTo("name", "Cali")
 db.collection("cities").whereGreaterThan("name", "Cali")
 db.collection("cities").whereGreaterThanOrEqualTo("name", "Cali")

但是我需要像这样的功能

But i need a function like as,

db.collection("cities").whereContain("name", "Cali")

应返回包含"Cali"子字符串的完整字符串.

which should return full string that contains 'Cali' substring.

推荐答案

不幸的是，Firestore中没有如下查询:

Unfortunately, there is no query in Firestore that looks like this:

db.collection("cities").whereContains("name", "Cali")

但是对于小型数据集，有一种解决方法可以帮助您解决此问题，方法是查询数据库以获取所有城市名称，并使用如下的contains()方法:

But for small datasets, there is a workaround that can help you solve this, which is by querying the database to get all city names and use contains() method like this:

String str1 = document.getString("yourProperty");
String str2 = "Cali";
boolean b = str1.toLowerCase().contains(str2.toLowerCase());

如果您尝试打印b的值，则会看到它是true.但是以上示例仅对小型数据集有效，而对于大型数据集则无效，这是因为下载整个集合以在客户端搜索字段是不切实际的.在这种情况下，根据官方文档的建议:

If you'll try to print the value of b, you'll see that is true. But the above examples works well enough only for small datasets, it doesn't work for large datasets and this is because downloading an entire collection to search for fields client-side isn't practical. In this case, as the official documentation recommends:

要启用Cloud Firestore数据的全文本搜索，请使用第三方搜索服务，例如 Algolia .

有关具体示例，请也从此

For a concrete example, please also see my answer from this post.

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