Let's say I have a data model with some optional properties. This could be for example a user object with a "firstname", a "lastname" and an optional "website" property.
In Cloud Firestore only user documents with a known website would have the "website" property set, for all other user documents this property would not exist.
My questions is now, how to query for all user documents without a "website" property?
Documents can contain properties with a null value data type (see data types documentation). This will then allow you to construct a query to limit results where the website property is null.
This is not quite the same as a missing property, but if you use custom objects to write data to Firestore, empty properties will automatically be saved as null rather than not at all. You can also manually/programmatically write a null value to the database.
In Android, I tested this using the following:
FirebaseFirestore.getInstance().collection("test").whereEqualTo("website", null).get();
Where my database structure looked like:
This returned only the document inuwlZOvZNTHuBakS6GV, because document 9Hf7uwORiiToOKz6zcsX contains a string value in the website property.
I believe you usually develop in Swift, where unfortunately custom objects aren't supported, but you can use NSNull() to write a null value to Firestore. For example (I'm not proficient in Swift, so feel free to correct any issues):
// Writing data
let docData: [String: Any] = [
"firstname": "Example",
"lastname": "User",
"website": NSNull()
]
db.collection("data").document("one").setData(docData) { err in
if let err = err {
print("Error writing document: \(err)")
} else {
print("Document successfully written!")
}
}
// Querying for null values
let query = db.collection("test").whereField("website", isEqualTo: NSNull())
The documentation doesn't mention a method to query for values that don't exist, so this seems like the next best approach. If anyone can improve or suggest alternatives, please do.
Related
There must be a better way to make upsert in Firebase Firestore in Kotlin.
I have collection of users that contains another collection userDocuments that contains field called highlights containing list of highlights.
I cannot use set and merge options as that will override the highlights list.
Any ideas how to make the code better. I do not like making two database requests on create and handling the failure like this. Maybe my database structure can be also optimized but I thought it is smart as all private userData will be stored in users collections with some subcollections.
My database structure is like this:
users -> {userId} -> userDocuments -> {docId} -> highlights ["this will be highlighted"]
users, and userDocuments are collections. Highlights is a field on userDocument.
docId might not yet be there, there will be 1000 of documents. And I do not want to add it to every user. I want it to be there, only when they make a change such as add or remove highlight to list of highlights.
usersCollection
.document(userId)
.collection("userDocuments")
.document(docId)
.update("highlights", FieldValue.arrayUnion(text))
.addOnFailureListener { err ->
// TODO should be handled differently
if (err is FirebaseFirestoreException &&
err.code === FirebaseFirestoreException.Code.NOT_FOUND
) {
val highlights = listOf(text)
usersCollection
.document(it)
.collection("userDocuments")
.document(docId)
.set(mapOf("highlights" to highlights), SetOptions.merge())
}
}
You can update using dictionary notation or dot notation too.
https://firebase.google.com/docs/firestore/manage-data/add-data#update_fields_in_nested_objects
db.collection("userDocuments")
.document(docId)
.update({
"highlights": FieldValue.arrayUnion(text)
});
You can consider using transactions as I mentioned in the comment above. But not sure if that is what you are looking for.
Inside my database i'm using fields of reference type on some documents, like this:
I'm trying to insert these property on firestore
_, err = userReference.Set(context.Background(), models.User{
Jobs: []*firestore.DocumentRef{employeeReference},
})
On this case I used an array of *DocumentRef, but even if is a unique DocumentRef doesn't work, I also tried to insert as type DocumentRef instead of the pointer, and also doesn't work, my User type is like that:
type User struct {
Jobs []*firestore.DocumentRef `json:"jobs"`
}
There's something that I can do to insert this type of data from go? On Javascript SDK, I remember that is only to insert the DocumentReference type directly on object that is achieved, but I'm facing this problem with Golang.
I have no experience with Golang but here you can find many examples.
I wonder if something like the following can give you any hints:
_, err := userReference.Set(context.Background(), models.User{
Jobs: []*firestore.DocumentRef{client.Doc("/selfManagedEmployees/K4qhd5k1c...")}
})
Let's say I have a data model with some optional properties. This could be for example a user object with a "firstname", a "lastname" and an optional "website" property.
In Cloud Firestore only user documents with a known website would have the "website" property set, for all other user documents this property would not exist.
My questions is now, how to query for all user documents without a "website" property?
Documents can contain properties with a null value data type (see data types documentation). This will then allow you to construct a query to limit results where the website property is null.
This is not quite the same as a missing property, but if you use custom objects to write data to Firestore, empty properties will automatically be saved as null rather than not at all. You can also manually/programmatically write a null value to the database.
In Android, I tested this using the following:
FirebaseFirestore.getInstance().collection("test").whereEqualTo("website", null).get();
Where my database structure looked like:
This returned only the document inuwlZOvZNTHuBakS6GV, because document 9Hf7uwORiiToOKz6zcsX contains a string value in the website property.
I believe you usually develop in Swift, where unfortunately custom objects aren't supported, but you can use NSNull() to write a null value to Firestore. For example (I'm not proficient in Swift, so feel free to correct any issues):
// Writing data
let docData: [String: Any] = [
"firstname": "Example",
"lastname": "User",
"website": NSNull()
]
db.collection("data").document("one").setData(docData) { err in
if let err = err {
print("Error writing document: \(err)")
} else {
print("Document successfully written!")
}
}
// Querying for null values
let query = db.collection("test").whereField("website", isEqualTo: NSNull())
The documentation doesn't mention a method to query for values that don't exist, so this seems like the next best approach. If anyone can improve or suggest alternatives, please do.
Let's say I have a data model with some optional properties. This could be for example a user object with a "firstname", a "lastname" and an optional "website" property.
In Cloud Firestore only user documents with a known website would have the "website" property set, for all other user documents this property would not exist.
My questions is now, how to query for all user documents without a "website" property?
Documents can contain properties with a null value data type (see data types documentation). This will then allow you to construct a query to limit results where the website property is null.
This is not quite the same as a missing property, but if you use custom objects to write data to Firestore, empty properties will automatically be saved as null rather than not at all. You can also manually/programmatically write a null value to the database.
In Android, I tested this using the following:
FirebaseFirestore.getInstance().collection("test").whereEqualTo("website", null).get();
Where my database structure looked like:
This returned only the document inuwlZOvZNTHuBakS6GV, because document 9Hf7uwORiiToOKz6zcsX contains a string value in the website property.
I believe you usually develop in Swift, where unfortunately custom objects aren't supported, but you can use NSNull() to write a null value to Firestore. For example (I'm not proficient in Swift, so feel free to correct any issues):
// Writing data
let docData: [String: Any] = [
"firstname": "Example",
"lastname": "User",
"website": NSNull()
]
db.collection("data").document("one").setData(docData) { err in
if let err = err {
print("Error writing document: \(err)")
} else {
print("Document successfully written!")
}
}
// Querying for null values
let query = db.collection("test").whereField("website", isEqualTo: NSNull())
The documentation doesn't mention a method to query for values that don't exist, so this seems like the next best approach. If anyone can improve or suggest alternatives, please do.
I am stuck trying to allow an an array of admins access to their data.
I have a database structure like this:
{
"Respondents": {
"Acme Corp": {
"admins": ["mMK7eTrRL4UgVDh284HntNRETmx1", ""mx1TERNmMK7eTrRL4UgVDh284Hnt"],
"data": {data goes here...}
},
"Another Inc": {
"admins": ["Dh284HmMK7eTrRL4UgVDh284HntN", ""x1TERNmx1TERNmMK7eTrRL4UgVDh"],
"data": {their data goes here...}
}
}
}
And then I tried to set my rules like this
{
"rules": {
"Respondents": {
"$organisation" : {
".read": "root.child('Respondents').child($organisation).child('admins').val().includes(auth.id)",
".read": "root.child('Respondents').child($organisation).child('admins').val().includes(auth.id)"
}
}
}
}
..but that won't parse in the Firebase Database Rules editor
I get "Error saving rules - Line 7: No such method/property 'includes'", but I need something to match the user id with the array of admins.
Any experience or suggestions?
As you've found, there is no includes() operation in Firebase's security rules. This is because Firebase doesn't actually store the data as an array. If you look in the Firebase Database console or read this blog post you will see that Firebase stores it as a regular object:
"admins": {
"0": "mMK7eTrRL4UgVDh284HntNRETmx1",
"1": "mx1TERNmMK7eTrRL4UgVDh284Hnt"
}
And since that is a regular JavaScript object, there is no contains() method on it.
In general creating arrays are an anti-pattern in the Firebase Database. They're often the wrong data structure and when used are regularly the main cause of scalability problems.
In this case: you're not really looking to store a sequence of UIDs. In fact: the order of the UIDs doesn't matter, and each UID can be meaningfully present in the collection at most once. So instead of an array, you're looking to store set of uids.
To implement a set in Firebase, you use this structure:
"admins": {
"mMK7eTrRL4UgVDh284HntNRETmx1": true,
"mx1TERNmMK7eTrRL4UgVDh284Hnt": true
}
The value doesn't matter much. But since you must have a value to store a key, it is idiomatic to use true.
Now you can test whether a key with the relevant UID exists under admins (instead of checking whether it contains a value):
"root.child('Respondents').child($organisation).child('admins').child(auth.uid).exists()",