I am hitting the following problem: Suppose that I have the following structure:
{
"id": 1,
"data": {
"arr": [{"text":"item1"}]
}
}
And the following query:
r.db('test').table('test').get(1).update(function (item) {
return {
data: {
arr: item('data')('arr').map(function (row) {
return r.branch(
row('text').eq('item1'),
row.merge({updated:true}),
row
)
})
}
}
})
I am listening for changes in this specific array only, and when the item is updated both create and delete events are emitted. I really need to receive an update event, e.g. old_val is not null and new_val is not null.
Thanks in advance guys
After all, I decided to drop the embedded array and use table joins, this avoids all possible hacks.
You can use something like this
r.db('test').table('test')('data')('arr').changes()
.filter(function(doc) {
return doc('new_val').ne(null).and(doc('old_val').ne(null))
})
I'll only show update to array. If you need to get access to other document field, try this:
r.db('test').table('test').changes()
.filter(function(doc) {
return doc('new_val')('data')('arr').ne(null).and(doc('old_val')('data')('arr').ne(null))
})
Related
I'm having the dexie stores showed in the print screen below:
Dexie stores print screen
My goal is to update a dexie field row from a store without losing the rest of the data.
For example: when I edit and save the field "com_name" from the second row (key={2}) I want to update "com_name" only and not lose the rest of the properties, see first and the third row.
I already tried with collection.modify and table.update but both deleted the rest of the properties when used the code below:
dexieDB.table('company').where('dexieKey').equals('{1}')
//USING table.update
//.update(dexieRecord.dexiekey, {
// company: {
// com_name: "TOP SERVE 2"
// }
//})
.modify(
{
company:
{
com_name: TOP SERVE 2
}
}
)
.then(function (updated) {
if (updated)
console.log("Success.");
else
console.log("Nothing was updated.");
})
.catch(function (err) { console.log(err); });
Any idea how can I accomplish that?
Thanks
Alex
You where right to use Table.update or Collection.modify. They should never delete other properties than the ones specified. Can you paste a jsitor.com or jsfiddle repro of that and someone may help you pinpoint why the code doesn't work as expected.
Now that you are saying I realised that company and contact stores are created dynamically and editedRecords store has the indexes explicitly declared therefore when update company or contact store, since dexie doesn't see the indexes will overwrite. I haven't tested it yet but I suspect this is the behaviour.
See the print screen below:
Dexie stores overview
Basically I have json raw data from db and in the browser I create the stores and stores data based on it, see code below:
function createDexieTables(jsonData) { //jsonData - array, is the json from db
const stores = {};
const editedRecordsTable = 'editedRecords';
jsonData.forEach((jsonPackage) => {
for (table in jsonPackage) {
if (_.find(dexieDB.tables, { 'name': table }) == undefined) {
stores[table] = 'dexieKey';
}
}
});
stores[editedRecordsTable] = 'dexieKey, table';
addDataToDexie(stores, jsonData);
}
function addDataToDexie(stores, jsonData) {
dbv1 = dexieDB.version(1);
if (jsonData.length > 0) {
dbv1.stores(stores);
jsonData.forEach((jsonPackage) => {
for (table in jsonPackage) {
jsonPackage[table].forEach((tableRow) => {
dexieDB.table(table).add(tableRow)
.then(function () {
console.log(tableRow, ' added to dexie db.');
})
.catch(function () {
console.log(tableRow, ' already exists.');
});
});
}
});
}
}
This is the json, which I convert to object and save to dexie in the value column and the key si "dexieKey":
[
{
"company": [
{
"dexieKey": "{1}",
"company": {
"com_pk": 1,
"com_name": "CloudFire",
"com_city": "Round Rock",
"serverLastEdit": [
{
"com_pk": "2021-06-02T11:30:24.774Z"
},
{
"com_name": "2021-06-02T11:30:24.774Z"
},
{
"com_city": "2021-06-02T11:30:24.774Z"
}
],
"userLastEdit": []
}
}
]
}
]
Any idea why indexes were not populated when generating them dynamically?
Given the JSON data, i understand what's going wrong.
Instead of passing the following to update():
{
company:
{
com_name: "TOP SERVE 2"
}
}
You probably meant to pass this:
{
"company.com_name": "TOP SERVE 2"
}
Another hint is to do the add within an rw transaction, or even better if you can use bulkAdd() instead to optimize the performance.
I have an array of objects from which I need to pass each object separately into async method (process behind is handled with Promise and then converted back to Observable via Observable.fromPromise(...) - this way is needed because the same method is used in case just single object is passed anytime; the process is saving objects into database). For example, this is an array of objects:
[
{
"name": "John",
...
},
{
"name": "Anna",
...
},
{
"name": "Joe",,
...
},
{
"name": "Alexandra",
...
},
...
]
Now I have the method called insert which which inserts object into database. The store method from database instance returns newly created id. At the end the initial object is copied and mapped with its new id:
insert(user: User): Observable<User> {
return Observable.fromPromise(this.database.store(user)).map(
id => {
let storedUser = Object.assign({}, user);
storedUser.id = id;
return storedUser;
}
);
}
This works well in case I insert single object. However, I would like to add support for inserting multiple objects which just call the method for single insert. Currently this is what I have, but it doesn't work:
insertAll(users: User[]): Observable<User[]> {
return Observable.forkJoin(
users.map(user => this.insert(user))
);
}
The insertAll method is inserting users as expected (or something else filled up the database with that users), but I don't get any response back from it. I was debugging what is happening and seems that forkJoin is getting response just from first mapped user, but others are ignored. Subscription to insertAll does not do anything, also there is no any error either via catch on insertAll or via second parameter in subscribe to insertAll.
So I'm looking for a solution where the Observable (in insertAll) would emit back an array of new objects with users in that form:
[
{
"id": 1,
"name": "John",
...
},
{
"id": 2,
"name": "Anna",
...
},
{
"id": 3,
"name": "Joe",,
...
},
{
"id": 4,
"name": "Alexandra",
...
},
...
]
I would be very happy for any suggestion pointing in the right direction. Thanks in advance!
To convert from array to observable you can use Rx.Observable.from(array).
To convert from observable to array, use obs.toArray(). Notice this does return an observable of an array, so you still need to .subscribe(arr => ...) to get it out.
That said, your code with forkJoin does look correct. But if you do want to try from, write the code like this:
insertAll(users: User[]): Observable<User[]> {
return Observable.from(users)
.mergeMap(user => this.insert(user))
.toArray();
}
Another more rx like way to do this would be to emit values as they complete, and not wait for all of them like forkJoin or toArray does. We can just omit the toArray from the previous example and we got it:
insertAll(users: User[]): Observable<User> {
return Observable.from(users)
.mergeMap(user => this.insert(user));
}
As #cartant mentioned, the problem might not be in Rx, it might be your database does not support multiple connections. In that case, you can replace the mergeMap with concatMap to make Rx send only 1 concurrent request:
insertAll(users: User[]): Observable<User[]> {
return Observable.from(users)
.concatMap(user => this.insert(user))
.toArray(); // still optional
}
How should we append an item to an array if the array exists, or create an array and insert to it.
I tried the merge command but that doesn't allow merging arrays, only replacing them.
r.db('testdb').table('users').get('27e55a4a-a6f8-4ec9-bd02-f55f206700ff').merge({ 'hobbies':['Reading'] })
I further tried passing a function but doesnt seem to work:
r.db('testdb').table('users').get('27e55a4a-a6f8-4ec9-bd02-f55f206700ff').merge(function(user) {
return r.branch(user('hobbies').eq(null),
{ 'hobbies' : ['Reading'] }
user('hobbies').append('Reading'))
});
Consider the below doc structure:
{
"email": email.123#gmail.com, »
"id": "27e55a4a-a6f8-4ec9-bd02-f55f206700ff" ,
"image": https://lh4.googleusercontent.com/-O4ZXcLRpkHE/AAArAAAAAAAI/AdAAAAAAALMM/Fq968TTkd88Y/photo.jpg?sz=50, »
"name": "John Doe"
}
If I would like to add hobbies as an array how should I do it. The query has to work both if the hobby array exists or not.
The most idiomatic way would be .update(function(user) { return {hobbies: user('hobbies').default([]).append('reading')}; })
Finally I have figured out myself.
r.db('testdb').table('users')
.get("27e55a4a-a6f8-4ec9-bd02-f55f206700ff")
.update(function(user){
return r.branch(user.hasFields('hobbies'),
{ hobbies: user('hobbies').append('reading')},
{ hobbies : ['reading']}
)})
Lets say I have a "category" table, each category has associated data in the "data" table and it has associated data in other tables "associated" and I want to remove a category with all it's associated data.
What I'm currently doing is something like this:
getAllDataIdsFromCategory()
.then(removeAllAssociated)
.then(handleChanges)
.then(removeDatas)
.then(handleChanges)
.then(removeCategory)
.then(handleChanges);
Is there a way to chain these queries on the db-side?
my functions currently look like this:
var getAllDataIdsFromCategory = () => {
return r
.table('data')
.getAll(categoryId, { index: 'categoryId' })
.pluck('id').map(r.row('id')).run();
}
var removeAllAssociated = (_dataIds: string[]) => {
dataIds = _dataIds;
return r
.table('associated')
.getAll(dataIds, { index: 'dataId' })
.delete()
.run()
}
var removeDatas = () => {
return r
.table('data')
.getAll(dataIds)
.delete()
.run()
}
notice that I cannot use r.expr() or r.do() since I want to do queries based on the result of the previous query.
The problem with my approach is that it won't work for large amounts of "data" since I have to bring all of the ids to the client side, and doing paging for it in the client side in a loop seems like a workaround.
You can use forEach for this:
r.table('data').getAll(categoryID, {index: 'categoryId'})('id').forEach(function(id) {
return r.table('associated').getAll(id, {index: 'dataId'}).delete().merge(
r.table('data').get(id).delete())
});
given sample data like:
{
'id': 1,
'things': [{'name': 'a'},{'name': 'b'},{'name': 'c'}]
}
how do I update the document removing the array item with name of 'b' from the embedded array?
r.table('test')
.get(1)
.update({things: r.row('things')????});
You can use the update command along with filter to filter the elements in an array and pass to along to update.
r.table('30848200').get(1).update(function (row) {
return {
'things': row('things')
.filter(function (item) { return item('name').ne('b') })
}
})
Basically, you'll be overwriting things with the filtered array.