How to get the average value from the firebase realtime database
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0
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My question is about getting the Avg rating from the database, and then updating the average rating every time a row is added.
This is the structure of my database in firebase.
I am trying to retrieve the Average rating of each ID (number like 299536), and update it every time new data/row is added for the same id.
I am using Firebase Realtime Database.
Any help is appreciated. I am using react.js. Should I create an action for this?
reactjs
firebase firebase-realtime-database asked Nov 11 at 23:11
lokanath
5817
add a comment |
up vote
0
down vote
favorite
My question is about getting the Avg rating from the database, and then updating the average rating every time a row is added.
This is the structure of my database in firebase.
I am trying to retrieve the Average rating of each ID (number like 299536), and update it every time new data/row is added for the same id.
I am using Firebase Realtime Database.
Any help is appreciated. I am using react.js. Should I create an action for this?
reactjs
firebase firebase-realtime-database asked Nov 11 at 23:11
lokanath
5817
How are you calculating the avg rating now?
– SakoBu
Nov 11 at 23:16
I was thinking of trying this way, const oldAvgRating = firebase.database().ref(movieinfo/${movieId}/avgRating); Then get the count of the rows for ID then, Add the current rating to the oldAvg and then divide by the count of rows +1.
– lokanath
Nov 11 at 23:18
That would give you access to the avg rating - yes...
– SakoBu
Nov 11 at 23:28
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
My question is about getting the Avg rating from the database, and then updating the average rating every time a row is added.
This is the structure of my database in firebase.
I am trying to retrieve the Average rating of each ID (number like 299536), and update it every time new data/row is added for the same id.
I am using Firebase Realtime Database.
Any help is appreciated. I am using react.js. Should I create an action for this?
reactjs
firebase firebase-realtime-database asked Nov 11 at 23:11
lokanath
5817
My question is about getting the Avg rating from the database, and then updating the average rating every time a row is added.
This is the structure of my database in firebase.
I am trying to retrieve the Average rating of each ID (number like 299536), and update it every time new data/row is added for the same id.
I am using Firebase Realtime Database.
Any help is appreciated. I am using react.js. Should I create an action for this?
reactjs
firebase firebase-realtime-database reactjs
firebase firebase-realtime-database asked Nov 11 at 23:11
lokanath
5817
asked Nov 11 at 23:11
lokanath
5817
asked Nov 11 at 23:11
lokanath
5817
asked Nov 11 at 23:11
lokanath
5817
asked Nov 11 at 23:11
lokanath
5817
5817
How are you calculating the avg rating now?
– SakoBu
Nov 11 at 23:16
I was thinking of trying this way, const oldAvgRating = firebase.database().ref(movieinfo/${movieId}/avgRating); Then get the count of the rows for ID then, Add the current rating to the oldAvg and then divide by the count of rows +1.
– lokanath
Nov 11 at 23:18
That would give you access to the avg rating - yes...
– SakoBu
Nov 11 at 23:28
add a comment |
How are you calculating the avg rating now?
– SakoBu
Nov 11 at 23:16
I was thinking of trying this way, const oldAvgRating = firebase.database().ref(movieinfo/${movieId}/avgRating); Then get the count of the rows for ID then, Add the current rating to the oldAvg and then divide by the count of rows +1.
– lokanath
Nov 11 at 23:18
That would give you access to the avg rating - yes...
– SakoBu
Nov 11 at 23:28
How are you calculating the avg rating now?
– SakoBu
Nov 11 at 23:16
How are you calculating the avg rating now?
– SakoBu
Nov 11 at 23:16
I was thinking of trying this way, const oldAvgRating = firebase.database().ref(
movieinfo/${movieId}/avgRating); Then get the count of the rows for ID then, Add the current rating to the oldAvg and then divide by the count of rows +1.– lokanath
Nov 11 at 23:18
I was thinking of trying this way, const oldAvgRating = firebase.database().ref(
movieinfo/${movieId}/avgRating); Then get the count of the rows for ID then, Add the current rating to the oldAvg and then divide by the count of rows +1.– lokanath
Nov 11 at 23:18
That would give you access to the avg rating - yes...
– SakoBu
Nov 11 at 23:28
That would give you access to the avg rating - yes...
– SakoBu
Nov 11 at 23:28
add a comment |
2 Answers
2
active
oldest
votes
up vote
2
down vote
If I understood your question correctly - something like this:
database.ref(`movieinfo/${movieId}/avgRating`)
.once('value')
.then((snapshot) => {
const val = snapshot.val();
console.log(val);
})
.catch((e) => {
console.log('Error fetching data', e);
});
answered Nov 11 at 23:31
SakoBu
913317
add a comment |
up vote
0
down vote
I would recommend abstracting this logic from your client side as you could have other apps and leaving open the avgRating for anyone to update wouldn't make it trust worthy. You can use a Cloud Function trigger for every rating that is created and run your logic there in a trusted environment and recalculate and update your avgRating Heres a page from the docs that explains creating a function
exports.calculateAvgRating = functions.database.ref('/moveinfo/{moveId}/{rating}')
.onCreate((snapshot, context) => {
// LOGIC GOES HERE e.g.
// Get a list of all your ratings
// Get average rating
// Update avgRating
}
answered Nov 12 at 11:55
Jack Woodward
62139
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
If I understood your question correctly - something like this:
database.ref(`movieinfo/${movieId}/avgRating`)
.once('value')
.then((snapshot) => {
const val = snapshot.val();
console.log(val);
})
.catch((e) => {
console.log('Error fetching data', e);
});
answered Nov 11 at 23:31
SakoBu
913317
add a comment |
up vote
2
down vote
If I understood your question correctly - something like this:
database.ref(`movieinfo/${movieId}/avgRating`)
.once('value')
.then((snapshot) => {
const val = snapshot.val();
console.log(val);
})
.catch((e) => {
console.log('Error fetching data', e);
});
answered Nov 11 at 23:31
SakoBu
913317
add a comment |
up vote
2
down vote
up vote
2
down vote
If I understood your question correctly - something like this:
database.ref(`movieinfo/${movieId}/avgRating`)
.once('value')
.then((snapshot) => {
const val = snapshot.val();
console.log(val);
})
.catch((e) => {
console.log('Error fetching data', e);
});
answered Nov 11 at 23:31
SakoBu
913317
If I understood your question correctly - something like this:
database.ref(`movieinfo/${movieId}/avgRating`)
.once('value')
.then((snapshot) => {
const val = snapshot.val();
console.log(val);
})
.catch((e) => {
console.log('Error fetching data', e);
});
answered Nov 11 at 23:31
SakoBu
913317
answered Nov 11 at 23:31
SakoBu
913317
answered Nov 11 at 23:31
SakoBu
913317
answered Nov 11 at 23:31
SakoBu
913317
913317
add a comment |
add a comment |
up vote
0
down vote
I would recommend abstracting this logic from your client side as you could have other apps and leaving open the avgRating for anyone to update wouldn't make it trust worthy. You can use a Cloud Function trigger for every rating that is created and run your logic there in a trusted environment and recalculate and update your avgRating Heres a page from the docs that explains creating a function
exports.calculateAvgRating = functions.database.ref('/moveinfo/{moveId}/{rating}')
.onCreate((snapshot, context) => {
// LOGIC GOES HERE e.g.
// Get a list of all your ratings
// Get average rating
// Update avgRating
}
answered Nov 12 at 11:55
Jack Woodward
62139
add a comment |
up vote
0
down vote
I would recommend abstracting this logic from your client side as you could have other apps and leaving open the avgRating for anyone to update wouldn't make it trust worthy. You can use a Cloud Function trigger for every rating that is created and run your logic there in a trusted environment and recalculate and update your avgRating Heres a page from the docs that explains creating a function
exports.calculateAvgRating = functions.database.ref('/moveinfo/{moveId}/{rating}')
.onCreate((snapshot, context) => {
// LOGIC GOES HERE e.g.
// Get a list of all your ratings
// Get average rating
// Update avgRating
}
answered Nov 12 at 11:55
Jack Woodward
62139
add a comment |
up vote
0
down vote
up vote
0
down vote
I would recommend abstracting this logic from your client side as you could have other apps and leaving open the avgRating for anyone to update wouldn't make it trust worthy. You can use a Cloud Function trigger for every rating that is created and run your logic there in a trusted environment and recalculate and update your avgRating Heres a page from the docs that explains creating a function
exports.calculateAvgRating = functions.database.ref('/moveinfo/{moveId}/{rating}')
.onCreate((snapshot, context) => {
// LOGIC GOES HERE e.g.
// Get a list of all your ratings
// Get average rating
// Update avgRating
}
answered Nov 12 at 11:55
Jack Woodward
62139
I would recommend abstracting this logic from your client side as you could have other apps and leaving open the avgRating for anyone to update wouldn't make it trust worthy. You can use a Cloud Function trigger for every rating that is created and run your logic there in a trusted environment and recalculate and update your avgRating Heres a page from the docs that explains creating a function
exports.calculateAvgRating = functions.database.ref('/moveinfo/{moveId}/{rating}')
.onCreate((snapshot, context) => {
// LOGIC GOES HERE e.g.
// Get a list of all your ratings
// Get average rating
// Update avgRating
}
answered Nov 12 at 11:55
Jack Woodward
62139
answered Nov 12 at 11:55
Jack Woodward
62139
answered Nov 12 at 11:55
Jack Woodward
62139
answered Nov 12 at 11:55
Jack Woodward
62139
62139
add a comment |
add a comment |
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How are you calculating the avg rating now?
– SakoBu
Nov 11 at 23:16
I was thinking of trying this way, const oldAvgRating = firebase.database().ref(
movieinfo/${movieId}/avgRating); Then get the count of the rows for ID then, Add the current rating to the oldAvg and then divide by the count of rows +1.– lokanath
Nov 11 at 23:18
That would give you access to the avg rating - yes...
– SakoBu
Nov 11 at 23:28