https://github.com/DefinitelyTyped/DefinitelyTyped/blob/bb1cc0e143f40f52a8d771e93036fc211df85cfb/types/nano/index.d.ts#L160
i am new to couch db and i know, i can use "fetch" if i want doc in result but i want doc in result based on some conditions when called with start_key and end_key. any help would be appreciated.
fetchRevs(
docnames: BulkFetchDocsWrapper,
params: DocumentFetchParams,
callback?: Callback<DocumentFetchRevsResponse>
): Request;
The fetchRevs endpoint is probably not what you want. I would take a look at the CouchDB API Overview and use:
PUT /mydb to create a database
PUT /mydb/docid to create a document in a database
GET /mydb/_all_docs?include_docs=true to retrieve all the documents
POST /mydb/_find to query the database
These API endpoints are modelled in the Typescript definition file you reference together with URLs that reference the API equivalents.
Related
How would you search for all resources for a given patient e.g. encounter, appointment, consent?
I know you could search for it via postman request http://localhost:9090/organId/Patient/12345/$everything and get the result. But I want to be able to execute the search query from my java program.
This is what I have so far, but I know the include part is not good and not working. Googling didn't return any result.
Bundle bundle = myFhirClient
.search()
.forResource(Patient.class)
.returnBundle(Bundle.class)
.where(new NumberClientParam(Patient.SP_RES_ID).exactly().number(patientId)).include(new Include("$everything"))
.sort(new SortSpec().setOrder(SortOrderEnum.DESC).setParamName(Patient.SP_RES_ID))
.execute();
Any help is much appreciated
I had to use Fhir Client operation instead of search. This will return all the reference resources for the given patientId.
Parameters outParams = myFhirClient
.operation()
.onInstance(new IdType("Patient", patientId))
.named("$everything")
.withNoParameters(Parameters.class) // No input parameters
.execute();
I recently started using Node.js + Express.js (generated with pug) + pg-promise for handling db.
My first target is to obtain data from Postgres (already set up) and display it pretty using render and pug. Let's say it is user list from Users table.
On this restful tutorial I have learned how to get data and return it as JSON - it worked.
Based on Mozilla's tutorial I seperated my code:
routes/users.js: where for '/' I call user_controller.user_list method (using router.get)
controllers/userController.js I have exported user_list where I would like to ask model for data and call render if I have results
queries.js which is kinda my model? But I'm not sure. It has API: connection to db with promises and one function for every query I am going to use in Controllers. I believe I should have like one Model file per table (or any logical entity) but where to store pgp connections?
This file is based on first tutorial I mentioned
// queries.js (connectionString is set properly to my postgres)
var pgp = require('pg-promise')(options);
var db = pgp(connectionString);
function getUsers(req, res, next) {
db.any('SELECT (user_id, username) FROM public.users ORDER BY user_id ASC LIMIT 1000')
.then(function (data) {
res.json({ data: data });
})
.catch(function (err) {
return next(err);
});
}
module.exports = {
getUsers: getUsers
};
Here starts my problem as most tutorials uses mongoose which is very model-db-schema-friendly and what I have is simple 'SELECT ...' string I pass to pg-promise's any() function.
Therefore I have no model class like User.
In userControllers.js I don't know how to call getUsers() to handle its data. Returning JS object from getUsers() would be nice.
Also: where should I call render? In controller or only in
db.any(...).then(function (data) { <--here--> })
Before, I also tried to embed whole Postgres handling into Controller but from db.any() I got this array for handling:
[{ row: '(1,John)' },{ row: '(2,Amy)' },{ row: '(50,Peter)' } ]
Didn't know how go from there as I probably lost my API functionality as well ;-)
I am browsing through multiple tutorials how to handle MVC but usually they handle MongoDB and
satisfy readers with res.send() not render().
I am not sure that I understand what your question is exactly about, but since I do not have enough reputation to comment, I'll do my best to help you with your interrogations. :)
First, regarding the queries.js file, it is IMO not exactly a model, but rather a DAO (Data Access Object) file. DAO comes between you Model (which is actually you database) and your Controller layers. There usually is a DAO file per object (User, Pet, whatever you want) in your data model.
When the data model is rather complex, it can be useful to use an Object Relational Mapping (ORM) such as Mongoose to map your database and execute complexe processes on your objects. In such a case, you might need a specific file per object so as to describe your model and store your queries. But since you don't need an ORM, you DAO can directly interact with your database. That is why you do not have a User.js file.
Regarding the way the db object should be used, I think you should refer directly to pg-promise documentation on the matter.
IMPORTANT: For any given connection, you should only create a single
Database object in a separate module, to be shared in your application
(see the code example below). If instead you keep creating the
Database object dynamically, your application will suffer from loss in
performance, and will be getting a warning in a development
environment (when NODE_ENV = development)
As a matter of fact, a db object in pg-promise sort of represents the database itself and is actually designed for the simultaneous use of several databases, which does not seem to be your case for the moment.
Finally, when it comes to the render function, I believe it should be in the controller, as your DAO is not supposed to know how the data it has gathered is going to be used.
Modularity is always a time-saving choice on the long-term.
Furthermore, note that you might later need a Business Layer between your DAO and your controller, in order to preprocess and postprocess data you are going to persist or to display. In such a case, if you need for instance to ask for data from your database, you will need to render data after it is processed by the Business layer. If the render is made in the DAO layer, it will not be possible.
In the link I provided earlier to pg-promise's db object connection, you will also find documentation on the any() method. You might already have looked it up.
It specifically states that it returns
A promise object that represents the query result:
When no rows are returned, it resolves with an empty array.
When 1 or more rows are returned, it resolves with the array of rows.
so your returned data is a JS Array. If you want to make it a JS object, just use
JSON.stringify(yourArray) to process your data before rendering it in your controller.
But I wonder if Pug is not able to use your data directly.
Also, if you cannot get any data out of your DAO, maybe you should check that your data object is not empty, as such a case is tolerated by the any() method. If you expect your query to always return something, you might want to consider using the many() or the one() methods.
I hope this helps you.
TLDR
Is there a way to limit queryByExample to a collection in NodeJS?
Problem faced
I have a complex query with some optional fields (i.e. sometimes some search fields will be omitted). So I need to create a query dynamically, e.g. in JSON. QueryByExample seems to be the right tool to use here as it gives me that flexibility to pass a JSON. However my problem is that I would like to limit my search to only one collection or directory.
e.g. I was hoping for something like
searchJSON = {
title: { $word: "test" },
description: { $word: "desc" }
};
//query
db.documents.query(qb.where(
qb.collection("collectionName"),
qb.byExample(searchJSON)
)).result()...
In this case searchJSON could have been built dynamically, for example maybe sometimes title may be omitted from the search.
This doesn't work because the query builder only allows queryByExample to be the only query. But I'd instead like to built a dynamic search query which is limited to a collection or directory.
At present, I think you would have to express the query with QueryBuilder instead of Query By Example using
qb.and([
qb.collection('collectionName'),
qb.word('title', 'test'),
qb.word('description', 'desc')
])
See http://docs.marklogic.com/jsdoc/queryBuilder.html#word
That said, it should be possible for the Node.js API to relax that restriction based on the fixes in MarkLogic 9.0-2
Please file an issue on https://github.com/marklogic/node-client-api
I am building a REST API which connects to a NEO4J instance. I am using the koa-neo4j library as the basis (https://github.com/assister-ai/koa-neo4j-starter-kit). I am a beginner at all these technologies but thanks to some help from this forum I have the basic functionality working. For example the below code allows me to create a new node with the label "metric" and set the name and dateAdded propertis.
URL:
/metric?metricName=Test&dateAdded=2/21/2017
index.js
app.defineAPI({
method: 'POST',
route: '/api/v1/imm/metric',
cypherQueryFile: './src/api/v1/imm/metric/createMetric.cyp'
});
createMetric.cyp"
CREATE (n:metric {
name: $metricName,
dateAdded: $dateAdded
})
return ID(n) as id
However, I am struggling to know how I can approach more complicated examples. How can I handle situations when I don't know how many properties will be added when creating a new node beforehand or when I want to create multiple nodes in a single post statement. Ideally I would like to be able to pass something like JSON as part of the POST which would contain all of the nodes, labels and properties that I want to create. Is something like this possible? I tried using the below Cypher query and passing a JSON string in the POST body but it didn't work.
UNWIND $props AS properties
CREATE (n:metric)
SET n = properties
RETURN n
Would I be better off switching tothe Neo4j Rest API instead of the BOLT protocol and the KOA-NEO4J framework. From my research I thought it was better to use BOLT but I want to have a Rest API as the middle layer between my front and back end so I am willing to change over if this will be easier in the longer term.
Thanks for the help!
Your Cypher syntax is bad in a couple of ways.
UNWIND only accepts a collection as its argument, not a string.
SET n = properties is only legal if properties is a map, not a string.
This query should work for creating a single node (assuming that $props is a map containing all the properties you want to store with the newly created node):
CREATE (n:metric $props)
RETURN n
If you want to create multiple nodes, then this query (essentially the same as yours) should work (but only if $prop_collection is a collection of maps):
UNWIND $prop_collection AS props
CREATE (n:metric)
SET n = props
RETURN n
I too have faced difficulties when trying to pass complex types as arguments to neo4j, this has to do with type conversions between js and cypher over bolt and there is not much one could do except for filing an issue in the official neo4j JavaScript driver repo. koa-neo4j uses the official driver under the hood.
One way to go about such scenarios in koa-neo4j is using JavaScript to manipulate the arguments before sending to Cypher:
https://github.com/assister-ai/koa-neo4j#preprocess-lifecycle
Also possible to further manipulate the results of a Cypher query using postProcess lifecycle hook:
https://github.com/assister-ai/koa-neo4j#postprocess-lifecycle
I'm writing a REST api in node js that will execute a sql query and send the results;
in the request I need to send the WHERE conditions; ex:
GET 127.0.0.1:5007/users //gets the list of users
GET 127.0.0.1:5007/users
id = 1 //gets the user with id 1
Right now the conditions are passed from the client to the rest api in the request's headers.
In the API I'm using sequelize, an ORM that needs to receive WHERE conditions in a particular form (an object); ex: having the condition:
(x=1 AND (y=2 OR z=3)) OR (x=3 AND y=1)
this needs to be formatted as a nested object:
-- x=1
-- AND -| -- y=2
| -- OR ----|
| -- z=3
-- OR -|
|
| -- x=3
-- AND -|
-- y=1
so the object would be:
Sequelize.or (
Sequelize.and (
{x=1},
Sequelize.or(
{y=2},
{z=3}
)
),
Sequelize.and (
{x=3},
{y=1}
)
)
Now I'm trying to pass a simple string (like "(x=1 AND (y=2 OR z=3)) OR (x=3 AND y=1)"), but then I will need a function on the server that can convert the string in the needed object (this method in my opinion has the advantage that the developer writing the client, can pass the where conditions in a simple way, like using sql, and this method is also indipendent from the used ORM, with no need to change the client if we need to change the server or use a different ORM);
The function to read and convert the conditions' string into an object is giving me headache (I'm trying to write one without success, so if you have some examples about how to do something like this...)
What I would like to get is a route capable of executing almost any kind of sql query and give the results:
now I have a different route for everything:
127.0.0.1:5007/users //to get all users
127.0.0.1:5007/users/1 //to get a single user
127.0.0.1:5007/lastusers //to get user registered in the last month
and so on for the other tables i need to query (one route for every kind of request I need in the client);
instead I would like to have only one route, something like:
127.0.0.1:5007/request
(when calling this route I will pass the table name and the conditions' string)
Do you think this solution would be a good solution or you generally use other ways to handle this kind of things?
Do you have any idea on how to write a function to convert the conditions' string into the desired object?
Any suggestion would be appreciated ;)
I would strongly advise you not to expose any part of your database model to your clients. Doing so means you can't change anything you expose without the risk of breaking the clients. One suggestion as far as what you've supplied is that you can and should use query parameters to cut down on the number of endpoints you've got.
GET /users //to get all users
GET /users?registeredInPastDays=30 //to get user registered in the last month
GET /users/1 //to get a single user
Obviously "registeredInPastDays" should be renamed to something less clumsy .. it's just an example.
As far as the conditions string, there ought to be plenty of parsers available online. The grammar looks very straightforward.
IMHO the main disadvantage of your solution is that you are creating just another API for quering data. Why create sthm from scratch if it is already created? You should use existing mature query API and focus on your business logic rather then inventing sthm new.
For example, you can take query syntax from Odata. Many people have been developing that standard for a long time. They have already considered different use cases and obstacles for query API.
Resources are located with a URI. You can use or mix three ways to address them:
Hierarchically with a sequence of path segments:
/users/john/posts/4711
Non hierarchically with query parameters:
/users/john/posts?minVotes=10&minViews=1000&tags=java
With matrix parameters which affect only one path segment:
/users;country=ukraine/posts
This is normally sufficient enough but it has limitations like the maximum length. In your case a problem is that you can't easily describe and and or conjunctions with query parameters. But you can use a custom or standard query syntax. For instance if you want to find all cars or vehicles from Ford except the Capri with a price between $10000 and $20000 Google uses the search parameter
q=cars+OR+vehicles+%22ford%22+-capri+%2410000..%2420000
(the %22 is a escaped ", the %24 a escaped $).
If this does not work for your case and you want to pass data outside of the URI the format is just a matter of your taste. Adding a custom header like X-Filter may be a valid approach. I would tend to use a POST. Although you just want to query data this is still RESTful if you treat your request as the creation of a search result resource:
POST /search HTTP/1.1
your query-data
Your server should return the newly created resource in the Location header:
HTTP/1.1 201 Created
Location: /search/3
The result can still be cached and you can bookmark it or send the link. The downside is that you need an additional POST.