英文:
How to delete a document in firestore by fetching its autogenerated id?
问题
如何在Firestore中删除文档或子文档，以及如何获取其自动生成的ID，以便当用户长按列表中的行项目并选择“删除”时，可以轻松地从应用程序的用户界面中删除文档。
英文:
How to delete a document or a sub-document in Firestore & how to fetch its auto-generated id so that when the user long presses, selects 'delete' on a row item in the list so that he/she can delete a document from the user interface of the app easily.
答案1
得分: 2
你无法“获取”现有的随机文档。为了删除文档，您需要执行以下两种操作之一：
- 在客户端上记住生成的ID，并使用该ID构建一个DocumentReference以删除该文档。
- 使用您在文档中已知的字段查询文档，然后在查询之后删除它。或者简单地查询所有文档，并将它们作为一组进行处理。
如果您无法使用其字段查询文档，也不知道其ID，那么您就陷入了困境，您需要更仔细地考虑数据模型。
英文:
You can't "fetch" an existing random document. In order to delete a document you need to do either one of two things:
- Remember the generated ID on the client, and use that to build a DocumetnReference to delete the document
- Query for the document using a field that you know in that document, then delete it after the query. Or simply query for all documents and work with them as a group.
If you can't query for a document using its fields, and you don't know it's ID, you're kind of stuck, and you will need to think more carefully about your data model.
答案2
得分: 1
如何在Firestore中删除文档或子文档
要删除文档，您需要使用 delete() 方法。
Kotlin 代码：
db.collection("你的集合名称").document("文档ID")
.delete()
.addOnSuccessListener { Log.d(TAG, "文档快照已成功删除！") }
.addOnFailureListener { e -> Log.w(TAG, "删除文档时出错", e) }
您需要知道要删除的文档的 集合名称 和 文档ID。使用您的 集合名称 和 文档ID 来从集合中删除文档。
查看这个链接了解更多信息。
如何获取自动生成的文档ID
要读取集合中的所有文档，您还需要知道 集合名称。
在 Kotlin 中读取集合中的文档：
db.collection("你的集合名称")
.get()
.addOnSuccessListener { result ->
for (document in result) {
Log.d(TAG, "${document.id} => ${document.data}")
}
}
.addOnFailureListener { exception ->
Log.d(TAG, "获取文档时出错：", exception)
}
document.id 将给您每个 文档ID。使用这个 文档ID 来删除文档。
要从集合中读取所有文档，请查看这个链接。
英文:
> How to delete a document or a sub-document in Firestore
To delete document you have to use delete() method
Kotlin Code:
db.collection("your_collection_name").document("documentId")
.delete()
.addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully deleted!") }
.addOnFailureListener { e -> Log.w(TAG, "Error deleting document", e) }
You need to know your collection name and documentId you want to delete. Use your collection name and documentId to delete a document from a collection.
Check this for more
> how to fetch its auto-generated id
To read all document in a collection you also need to know collection name.
To read documents in a collection in Kotlin:
db.collection("your_collection_name")
.get()
.addOnSuccessListener { result ->
for (document in result) {
Log.d(TAG, "${document.id} => ${document.data}")
}
}
.addOnFailureListener { exception ->
Log.d(TAG, "Error getting documents: ", exception)
}
document.id will give you every documentId. Use this documentId to delete a document.
To read all documents from a collection check this
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