In couchbase, I was wondering if there was a way - WITHOUT using a view - to iterate through database keys. The admin interface appears to do this, but maybe its doing something special. What I'd like to is make a call like this to retrieve an array of keys:
$result = $cb->get("KEY_ALBERT", "KEY_FRED");
having the result be an array [KEY_ALEX, KEY_BOB, KEY_DOGBERT]
Again, I don't want to use a view unless there's no alternative. Doesn't look like its possible, but since the "view documents" in the admin appears to do this, I thought i'd double-check. I'm using the php interface if that matters.
Based on your comments, the only way is to create a simple view that emit only the id as par of the key:
function(doc, meta) {
emit( meta.id );
}
With this view you will be able to create query with the various options you need :
- pagination, range, ...
Note: you talk about the Administration Console, the console use an "internal view" that is similar to what I have written above (but not optimized)
I don't know about how couchbase admin works, but there are two options. First option is to store your docs as linked list, one doc have property (key) that points to another doc.
docs = [
{
id: "doc_C",
data: "somedata",
prev: "doc_B",
next: "doc_D"
},
{
id: "doc_D",
data: "somedata",
prev: "doc_C",
next: "doc_E"
}
]
The second approach is to use sequential id. You should have one doc that contain sequence and increment it on each add. It would be something like this:
docs = [
{
id: "doc_1",
data: "somedata"
},
{
id: "doc_2",
data: "somedata"
}
...
]
In this way you can do "range requests". To do this you form array of keys on server side:
[doc_1, doc_2 .... doc_N]and execute multiget query. Here is also a link to another example
The couchbase PHP sdk does support multiget requests. For a list of keys it will return an array of documents.
getMulti(array $ids, array $cas, int $flags) : array
http://www.couchbase.com/autodocs/couchbase-php-client-1.1.5/classes/Couchbase.html#method_getMulti
Related
{
"movies": {
"movie1": {
"genre": "comedy",
"name": "As good as it gets",
"lead": "Jack Nicholson"
},
"movie2": {
"genre": "Horror",
"name": "The Shining",
"lead": "Jack Nicholson"
},
"movie3": {
"genre": "comedy",
"name": "The Mask",
"lead": "Jim Carrey"
}
}
}
I am a Firebase newbie. How can I retrieve a result from the data above where genre = 'comedy' AND lead = 'Jack Nicholson'?
What options do I have?
Using Firebase's Query API, you might be tempted to try this:
// !!! THIS WILL NOT WORK !!!
ref
.orderBy('genre')
.startAt('comedy').endAt('comedy')
.orderBy('lead') // !!! THIS LINE WILL RAISE AN ERROR !!!
.startAt('Jack Nicholson').endAt('Jack Nicholson')
.on('value', function(snapshot) {
console.log(snapshot.val());
});
But as #RobDiMarco from Firebase says in the comments:
multiple orderBy() calls will throw an error
So my code above will not work.
I know of three approaches that will work.
1. filter most on the server, do the rest on the client
What you can do is execute one orderBy().startAt()./endAt() on the server, pull down the remaining data and filter that in JavaScript code on your client.
ref
.orderBy('genre')
.equalTo('comedy')
.on('child_added', function(snapshot) {
var movie = snapshot.val();
if (movie.lead == 'Jack Nicholson') {
console.log(movie);
}
});
2. add a property that combines the values that you want to filter on
If that isn't good enough, you should consider modifying/expanding your data to allow your use-case. For example: you could stuff genre+lead into a single property that you just use for this filter.
"movie1": {
"genre": "comedy",
"name": "As good as it gets",
"lead": "Jack Nicholson",
"genre_lead": "comedy_Jack Nicholson"
}, //...
You're essentially building your own multi-column index that way and can query it with:
ref
.orderBy('genre_lead')
.equalTo('comedy_Jack Nicholson')
.on('child_added', function(snapshot) {
var movie = snapshot.val();
console.log(movie);
});
David East has written a library called QueryBase that helps with generating such properties.
You could even do relative/range queries, let's say that you want to allow querying movies by category and year. You'd use this data structure:
"movie1": {
"genre": "comedy",
"name": "As good as it gets",
"lead": "Jack Nicholson",
"genre_year": "comedy_1997"
}, //...
And then query for comedies of the 90s with:
ref
.orderBy('genre_year')
.startAt('comedy_1990')
.endAt('comedy_2000')
.on('child_added', function(snapshot) {
var movie = snapshot.val();
console.log(movie);
});
If you need to filter on more than just the year, make sure to add the other date parts in descending order, e.g. "comedy_1997-12-25". This way the lexicographical ordering that Firebase does on string values will be the same as the chronological ordering.
This combining of values in a property can work with more than two values, but you can only do a range filter on the last value in the composite property.
A very special variant of this is implemented by the GeoFire library for Firebase. This library combines the latitude and longitude of a location into a so-called Geohash, which can then be used to do realtime range queries on Firebase.
3. create a custom index programmatically
Yet another alternative is to do what we've all done before this new Query API was added: create an index in a different node:
"movies"
// the same structure you have today
"by_genre"
"comedy"
"by_lead"
"Jack Nicholson"
"movie1"
"Jim Carrey"
"movie3"
"Horror"
"by_lead"
"Jack Nicholson"
"movie2"
There are probably more approaches. For example, this answer highlights an alternative tree-shaped custom index: https://stackoverflow.com/a/34105063
If none of these options work for you, but you still want to store your data in Firebase, you can also consider using its Cloud Firestore database.
Cloud Firestore can handle multiple equality filters in a single query, but only one range filter. Under the hood it essentially uses the same query model, but it's like it auto-generates the composite properties for you. See Firestore's documentation on compound queries.
I've written a personal library that allows you to order by multiple values, with all the ordering done on the server.
Meet Querybase!
Querybase takes in a Firebase Database Reference and an array of fields you wish to index on. When you create new records it will automatically handle the generation of keys that allow for multiple querying. The caveat is that it only supports straight equivalence (no less than or greater than).
const databaseRef = firebase.database().ref().child('people');
const querybaseRef = querybase.ref(databaseRef, ['name', 'age', 'location']);
// Automatically handles composite keys
querybaseRef.push({
name: 'David',
age: 27,
location: 'SF'
});
// Find records by multiple fields
// returns a Firebase Database ref
const queriedDbRef = querybaseRef
.where({
name: 'David',
age: 27
});
// Listen for realtime updates
queriedDbRef.on('value', snap => console.log(snap));
var ref = new Firebase('https://your.firebaseio.com/');
Query query = ref.orderByChild('genre').equalTo('comedy');
query.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot movieSnapshot : dataSnapshot.getChildren()) {
Movie movie = dataSnapshot.getValue(Movie.class);
if (movie.getLead().equals('Jack Nicholson')) {
console.log(movieSnapshot.getKey());
}
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
}
});
Frank's answer is good but Firestore introduced array-contains recently that makes it easier to do AND queries.
You can create a filters field to add you filters. You can add as many values as you need. For example to filter by comedy and Jack Nicholson you can add the value comedy_Jack Nicholson but if you also you want to by comedy and 2014 you can add the value comedy_2014 without creating more fields.
{
"movies": {
"movie1": {
"genre": "comedy",
"name": "As good as it gets",
"lead": "Jack Nicholson",
"year": 2014,
"filters": [
"comedy_Jack Nicholson",
"comedy_2014"
]
}
}
}
For Cloud Firestore
https://firebase.google.com/docs/firestore/query-data/queries#compound_queries
Compound queries
You can chain multiple equality operators (== or array-contains) methods to create more specific queries (logical AND). However, you must create a composite index to combine equality operators with the inequality operators, <, <=, >, and !=.
citiesRef.where('state', '==', 'CO').where('name', '==', 'Denver');
citiesRef.where('state', '==', 'CA').where('population', '<', 1000000);
You can perform range (<, <=, >, >=) or not equals (!=) comparisons only on a single field, and you can include at most one array-contains or array-contains-any clause in a compound query:
Firebase doesn't allow querying with multiple conditions.
However, I did find a way around for this:
We need to download the initial filtered data from the database and store it in an array list.
Query query = databaseReference.orderByChild("genre").equalTo("comedy");
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
ArrayList<Movie> movies = new ArrayList<>();
for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
String lead = dataSnapshot1.child("lead").getValue(String.class);
String genre = dataSnapshot1.child("genre").getValue(String.class);
movie = new Movie(lead, genre);
movies.add(movie);
}
filterResults(movies, "Jack Nicholson");
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
Once we obtain the initial filtered data from the database, we need to do further filter in our backend.
public void filterResults(final List<Movie> list, final String genre) {
List<Movie> movies = new ArrayList<>();
movies = list.stream().filter(o -> o.getLead().equals(genre)).collect(Collectors.toList());
System.out.println(movies);
employees.forEach(movie -> System.out.println(movie.getFirstName()));
}
The data from firebase realtime database is as _InternalLinkedHashMap<dynamic, dynamic>.
You can also just convert this it to your map and query very easily.
For example, I have a chat app and I use realtime database to store the uid of the user and the bool value whether the user is online or not. As the picture below.
Now, I have a class RealtimeDatabase and a static method getAllUsersOnineStatus().
static getOnilineUsersUID() {
var dbRef = FirebaseDatabase.instance;
DatabaseReference reference = dbRef.reference().child("Online");
reference.once().then((value) {
Map<String, bool> map = Map<String, bool>.from(value.value);
List users = [];
map.forEach((key, value) {
if (value) {
users.add(key);
}
});
print(users);
});
}
It will print [NOraDTGaQSZbIEszidCujw1AEym2]
I am new to flutter If you know more please update the answer.
ref.orderByChild("lead").startAt("Jack Nicholson").endAt("Jack Nicholson").listner....
This will work.
I'm using Terraform to create an AWS EMR cluster that uses spot instances as core instances.
I know I can use the bid_price variable within the core_instance_group block on a aws_emr_cluster resource, but I don't want to hardcode prices as I'd have to change them manually every time the instance type changes.
Using the AWS Web UI, I'm able to choose the "Use on-demand as max price" option. That's exactly what I'm trying to reproduce, but in Terraform.
Right now I am trying to solve my problem using the aws_pricing_product data source. You can see what I have so far below:
data "aws_pricing_product" "m4_large_price" {
service_code = "AmazonEC2"
filters {
field = "instanceType"
value = "m4.large"
}
filters {
field = "operatingSystem"
value = "Linux"
}
filters {
field = "tenancy"
value = "Shared"
}
filters {
field = "usagetype"
value = "BoxUsage:m4.large"
}
filters {
field = "preInstalledSw"
value = "NA"
}
filters {
field = "location"
value = "US East (N. Virginia)"
}
}
data.aws_pricing_product.m4_large_price.result returns a json containing the details of a single product (you can check the response of the example here). The actual on-demand price is buried somewhere inside this json, but I don't know how can I get it (image generated with http://jsonviewer.stack.hu/):
I know I might be able solve this by using an external data source and piping the output of an aws cli call to something like jq, e.g:
aws pricing get-products --filters "Type=TERM_MATCH,Field=sku,Value=8VCNEHQMSCQS4P39" --format-version aws_v1 --service-code AmazonEC2 | jq [........]
But I'd like to know if there is any way to accomplish what I'm trying to do with pure Terraform. Thanks in advance!
Unfortunately the aws_pricing_product data source docs don't expand on how it should be used effectively but the discussion in the pull request that added it adds some insight.
In Terraform 0.12 you should be able to use the jsondecode function to nicely get at what you want with the following given as an example in the linked pull request:
data "aws_pricing_product" "example" {
service_code = "AmazonRedshift"
filters = [
{
field = "instanceType"
value = "ds1.xlarge"
},
{
field = "location"
value = "US East (N. Virginia)"
},
]
}
# Potential Terraform 0.12 syntax - may change during implementation
# Also, not sure about the exact attribute reference architecture myself :)
output "example" {
values = jsondecode(data.json_query.example.value).terms.OnDemand.*.priceDimensions.*.pricePerUnit.USD
}
If you are stuck on Terraform <0.12 you might struggle to do this natively in Terraform other than the external data source approach you've already suggested.
#cfelipe put that ${jsondecode(data.aws_pricing_product.m4_large_price.value).terms.OnDemand.*.priceDimensions.*.pricePerUnit.USD}" in a Locals
I am going to implement the REST base CRUD modal in my my app.I wan to display the list of product data with edit and delete link
Product
id, title, unit_id, product_type_id, currency_id,price
Q1: what should be json response look like?
There are two formats comes in my mind to place the data in Json as a response of REST Get call
[
{
id:1,
title:"T-Shirt",
unit_id:20,
unit_title: "abc"
product_type_id:30,
product_type_title:"xyz"
currency_id: 10,
currency_name: "USD"
min_price:20
},
{...}
]
and the another one is
[
{
id:1,
title:"T-Shirt",
unit: {
id: 20,
title: "abc"
},
product_type: {
id: 30,
title: "xyz"
},
currency_id: {
id:10,
name: "USD"
},
min_price:20
},
{...}
]
what is the better and standard way to handle the above scenario?
Furthermore, let suppose I have 10 more properties in product table which will never display on list page. but i needed it when user going to edit the specific item.
Q2: Should I the load all data once at the time of displaying product list and pass the data to edit component.
or
Load only the needed propeties of product table and pass the id to produt edit component and a new REST GET call with id to get the properties of product.
I am using React + Redux for my front end
Typically, you would create additional methods for API consumers to retrieve the values that populate the lists of currency, product_type and unit when editing in a UI.
I wouldn't return more data than necessary for an individual Product object.
I'm using Postman to make REST API calls to a server. I want to make the name field dynamic so I can run the request with a unique name every time.
{
"location":
{
"name": "Testuser2", // this should be unique, eg. Testuser3, Testuser4, etc
"branding_domain_id": "52f9f8e2-72b7-0029-2dfa-84729e59dfee",
"parent_id": "52f9f8e2-731f-b2e1-2dfa-e901218d03d9"
}
}
In Postman you want to use Dynamic Variables.
The JSON you post would look like this:
{
"location":
{
"name": "{{$guid}}",
"branding_domain_id": "52f9f8e2-72b7-0029-2dfa-84729e59dfee",
"parent_id": "52f9f8e2-731f-b2e1-2dfa-e901218d03d9"
}
}
Note that this will give you a GUID (you also have the option to use ints or timestamps) and I'm not currently aware of a way to inject strings (say, from a test file or a data generation utility).
In Postman you can pass random integer which ranges from 0 to 1000, in your data you can use it as
{
"location":
{
"name": "Testuser{{$randomInt}}",
"branding_domain_id": "52f9f8e2-72b7-0029-2dfa-84729e59dfee",
"parent_id": "52f9f8e2-731f-b2e1-2dfa-e901218d03d9"
}
}
Just my 5 cents to this matter. When using randomInt there is always a chance that the number might eventually be present in the DB which can cause issues.
Solution (for me at least) is to use $timestamp instead.
Example:
{
"username": "test{{$timestamp}}",
"password": "test"
}
For anyone who's about to downvote me this post was made before the discussion in comments with the OP (see below). I'm leaving it in place so the comment from the OP which eventually described what he needs isn't removed from the question.
From what I understand you're looking for, here's a basic solution. It's assuming that:
you're developing some kind of script where you need test data
the name field should be unique each time it's run
If your question was more specific then I'd be able to give you a more specific answer, but this is the best I can do from what's there right now.
var counter = location.hash ? parseInt(location.hash.slice(1)) : 1; // get a unique counter from the URL
var unique_name = 'Testuser' + counter; // create a unique name
location.hash = ++counter; // increase the counter by 1
You can forcibly change the counter by looking in the address bar and changing the URL from ending in #1 to #5, etc.
You can then use the variable name when you build your object:
var location = {
name: unique_name,
branding_domain_id: 'however-you-currently-get-it',
parent_id: 'however-you-currently-get-it'
};
Add the below text in pre-req:
var myUUID = require('uuid').v4();
pm.environment.set('myUUID', myUUID);
and use the myUUID wherever you want
like
name: "{{myUUID}}"
It will generate a random unique GUID for every request
var uuid = require('uuid');
pm.globals.set('unique_name', 'testuser' + uuid.v4());
add above code to the pre-request tab.
this was you can reuse the unique name for subsequent api calls.
Dynamic variable like randomInt, or guid is dynamic ie : you donot know what was send in the request. there is no way to refer it again, unless it is send back in response. even if you store it in a variable,it will still be dynamic
another way is :
var allowed = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
var shuffled_unique_str = allowed.split('').sort(function(){return 0.5-Math.random()}).join('');
courtsey refer this link for more options
To begin with I'd like to say I know how to create ugly solutions for my problem. I am searching good solutions and best practices :)
How do I create deep hierarchial arrays (to json_encode later) from Kohana 3 ORM objects including related objects where the relation type is one-to-many?
The problem is that the ORM->as_array() method does work recursively for the "has one" and "belongs to" relationships but will stop and force you to use ->find_all() manually when you encounter a "has many" relationship.
Say I am creating a JSON API REST server using Kohana 3 and the built in ORM.
When someone looks at this URL: www.example.com/api/user?id=5
They will be served a JSON object for the user where id=5.
These are the orm-models and the relations:
User belongs to a Country
User has many Messages.
Message belongs to a Category
I would like this to work:
echo json_encode(
ORM::factory('user', 5)
->with('country')
->with('messages')
->with('messages:category')
->find()
->as_array()
);
and give me output like this:
{
name: "John"
age: 54,
country_id: 5,
country: {
name: 'Sweden',
code: 'SE'
},
messages: {
{
content: 'Lorem ipsum dolor...',
category_id: 1,
category: {...}
},
{
content: 'Sit amet elit...',
category_id: 2,
category: {...}
},
{
content: 'Consectetur ipsum dolor...',
category_id: 3,
category: {...}
}
}
}
BUT THAT WONT WORK.
This is all you would get:
{
name: "John"
age: 54,
country_id: 5,
country: {
name: 'Sweden',
code: 'SE'
}
}
Has someone forked or extended the Kohana 3 ORM to support this kind functionality?
Does someone know of any good Kohana 3 api module that takes care of this issue for you somehow?
As far as I know, there is no way to do this using only the ORM. This is the case for two reasons:
If a message has a relation for category, that usually means that category has a corresponding relation for the messages in the category. If you want to get the message "in full" - i.e. including its category - let's say that you also want to get the category "in full" - i.e. including its messages. This is obviously a very bad idea, as you could very easily design yourself into an infinite loop. In other words, if there was a magic "recurse all relations" capability, how would it know when to stop recursing?
All that the ORM is doing behind the scenes when you call find() is building a SQL query that returns a row of data from the database. However, what you are trying to do is too complicated for a single query that returns a single row. (There is a way to retrieve multiple rows as one row with comma-separated values in each field using MySQL's GROUP_CONCAT function, but I guarantee you that it is not worth the trouble.)
For both of these reasons, the ORM's with() method only works on belongs_to (in your case, the user's country and the message's category).
One way to do this query is to break it up into three steps, like this:
// Step 1: Get the user
$user = ORM::factory('user', 5)
->with('country')
->find();
// Step 2: Get the messages
$user->messages
->with('category')
->find_all();
// Step 3: Make user and the messages into arrays.
// User is easy, but messages are a little harder
// because they need to turn
// from "an object containing an array of objects"
// into "an array of arrays."
$user_arr = $user->as_array();
$fixer = function($obj)
{
return $obj->as_array();
};
$user_arr['messages'] = array_map($fixer, $user->messages->as_array());
// Now you can output it
echo json_encode($user_arr);