Graphml-views-mongodb

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A library that enable views for MongoDB based on [GraphML], which generates collections
from MongoDB datasources by given graphml files.

Installation

``sh
$ npm install graphml-views-mongodb --save
`

Why create this?

The original MongoDB doesn't support view like CouchDB and other SQL-Like database. And
it supports the following ways to make relations between multiple collections:

- embed documents
- DBRef type to reference to other database

$3

The embed documents even though has a avilability for retrieving data, but lack of consistency
on writing data on the embeded documents.

The DBRef is not recommended way to take the role of expressing relations, we should use it
to reference a value to another database that maybe in other system.

$3

The next context is about [Loopback], the framework to replace the role of Parse and LeanCloud,
the framework abstracts most popluar databases into the same one schema, and it support rich relations
as below:

- one-to-one
- one-to-many

That's good, but not enough, because [Loopback]'s scoping/joining syntax is such complicated so that
the request URLs would become too long and unreadability. So sometimes, the truth is that we want a collection
is for a view, and we just query it directly from the collection without scoping and joining. At the same time,
for write operations, we hope that model-based would be used and it will updates data to the view collections.

$3

In starting this project, we tried JSON, YAML and TOML to express what fields would be in our view collection,
but they are almost out after having a try on GraphQL, and then we found GraphQL is the QL for querying, so we,
the [WeFlex] team decoded to rewrite a new marked language based on basic of [GraphQL], that's the [GraphML].

To express a view, you just need the following:

`
User {
username,
nickname,
sex,
country,
orgs {
name
},
followings {
username,
avatarUrl
},
followers {
username,
avatarUrl
}
}
`

Then you will get document:

`JSON
{
"_id": "id",
"username": "yorkie",
"nickname": "yorkie",
"sex": "female",
"country": "internet",
"orgs": [
{
"_id": "weflex_id",
"name": "weflex"
}
],
"followings": [
{
"_id": "following_id",
"name": "substack",
"avatarUrl": "image url"
}
],
"followers": [
{
"_id": "follower_id",
"name": "scott",
"avatarUrl": "image url"
}
]
}
`

$3

The [Graphml-views-mongodb] does parse a GraphML file and get fields collection that you want to include from
the source collections, and read the relations from pre-defined [Loopback] models, and generate the complete
documents.

API

- parseGraphs(models, dataSources)
- models {Array} the object returned from loopback
- dataSources {Object} the object to take dataSources
- rest {MongoDB} the resouce database instance
- view {MongoDB} the view database instance
- dir` the dirname path

License

MIT @ WeFlex, Inc.

[Graphml-views-mongodb]: https://github.com/weflex/graphml-views-mongodb
[GraphQL]: https://github.com/facebook/graphql
[GraphML]: https://github.com/weflex/graphml
[Loopback]: https://github.com/strongloop/loopback
[WeFlex]: https://github.com/weflex

[npm-image]: https://img.shields.io/npm/v/graphml-views-mongodb.svg?style=flat-square
[npm-url]: https://npmjs.org/package/graphml-views-mongodb
[travis-image]: https://img.shields.io/travis/weflex/graphml-views-mongodb.svg?style=flat-square
[travis-url]: https://travis-ci.org/weflex/graphml-views-mongodb
[david-image]: http://img.shields.io/david/weflex/graphml-views-mongodb.svg?style=flat-square
[david-url]: https://david-dm.org/weflex/graphml-views-mongodb
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[downloads-url]: https://npmjs.org/package/graphml-views-mongodb