how to query in firestore
db.collection("cities").where("capital", "==", true)
.get()
.then(function(querySnapshot) {
querySnapshot.forEach(function(doc) {
// doc.data() is never undefined for query doc snapshots
console.log(doc.id, " => ", doc.data());
});
})
.catch(function(error) {
console.log("Error getting documents: ", error);
});read data firestore java
DocumentReference docRef = db.collection("cities").document("SF");
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
Log.d(TAG, "DocumentSnapshot data: " + document.getData());
} else {
Log.d(TAG, "No such document");
}
} else {
Log.d(TAG, "get failed with ", task.getException());
}
}
});get data in from a collection firestore
db.collection("users").get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
console.log(`${doc.id} => ${doc.data()}`);
});get data from firebase firestore
useEffect(() => {
db.collection('posts')
.orderBy('timestamp', 'asc') // optional
.onSnapshot((snapshot) => {
setPosts(
snapshot.docs.map((doc) => {
return doc.data();
})
);
});
}, []);get data from firestore
const [hospitalsDetails, setHospitalsDetails] = useState([])
useEffect(()=>{
//load hospitals into hospitalsList
const hospitals = []
db.collection('Hospitals').get()
.then(snapshot => {
snapshot.docs.forEach(hospital => {
let currentID = hospital.id
let appObj = { ...hospital.data(), ['id']: currentID }
hospitals.push(appObj)
hospitals.push(hospital.data())
})
setHospitalsDetails(hospitals)
})
},[])Copyright © 2021 Codeinu
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