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https://github.com/2do2go/mongodbext-relations
mongodbext plugin that bring relations between collections
https://github.com/2do2go/mongodbext-relations
Last synced: 29 days ago
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mongodbext plugin that bring relations between collections
- Host: GitHub
- URL: https://github.com/2do2go/mongodbext-relations
- Owner: 2do2go
- License: mit
- Created: 2017-04-28T09:37:07.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2023-03-04T01:14:56.000Z (almost 2 years ago)
- Last Synced: 2024-12-03T05:03:00.851Z (about 1 month ago)
- Language: JavaScript
- Size: 68.4 KB
- Stars: 1
- Watchers: 6
- Forks: 4
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# mongodbext-relations
mongodbext plugin that bring relations between collections
**Starting from `[email protected]` supports mongodb 3.6+ only**
**options:**
* `relations` (required) - hash of fields that should be embedded, should be specified in format: `{field1: field1Options, field2: fieldOptions, ...}`.
Each field options could have properties:
* `collection` (required) - instance of mongodbext collection, that should be embedded
* `projection` - fields projection to embed (`{_id: 1}` by default`)
* `key` - "primary key" field (`_id` by default)
* `embedded` - function that used to create EmbeddedDocument instance (autogenerated by default)
* `onDelete` - action that should be done on embedded document deletion, available actions: 'restrict', 'cascade', 'unset', 'pull', null ('restrict' by default)
* `onUpdate` - action that should be done on embedded document updation, available actions: `cascade`, null ('cascade' by default)
**Example:**
``` js
var MongoClient = require('mongodb').MongoClient;
var mongodbext = require('mongodbext');
var mongodbextRelations = require('mongodbext-relations');
MongoClient.connect('mongodb://localhost:27017/test', function(err, db) {
var authorsCol = new mongodbext.Collection(db, 'authors');
var chaptersCol = new mongodbext.Collection(db, 'chapters');
var booksCol = new mongodbext.Collection(db, 'books');
booksCol.addPlugin(mongodbextRelations, {
relations: {
'author': {
collection: authorsCol,
projection: {_id: 1, name: 1}
},
'chapters.$': {
collection: chaptersCol,
projection: {_id: 1, title: 1}
}
}
});
var author = {
_id: 1,
name: 'John Doe',
age: 42
};
var chapters = [{
_id: 1,
title: 'Chapter 1',
page: 6
}, {
_id: 2,
title: 'Chapter 2',
page: 100
}];
var book = {
_id: 1,
title: 'Book',
author: 1,
chapters: [1, 2]
};
authorsCol.insertOne(author, function() {
chaptersCol.insertMany(chapters, function() {
booksCol.insertOne(book, function(err, book) {
console.log(book);
// {
// _id: 1,
// title: 'Book',
// author: { _id: 1, name: 'John Doe' },
// chapters: [
// { _id: 1, title: 'Chapter 1' },
// { _id: 2, title: 'Chapter 2' }
// ]
// }
chaptersCol.deleteOne({_id: 1}, function(err) {
console.log(err);
// [Error: Could not delete document from collection `chapters` because it is embedded to related collection `books` in the field `chapters` of document with _id=1]
});
});
});
});
});
```
**skipping additional db requests with `trustEmbeddedValue` flag:**
Relations plugin adds new `trustEmbeddedValue` option to the following methods:
* `insertOne`
* `insertMany`
* `updateOne`
* `updateMany`
* `upsertOne`
* `replaceOne`
* `findOneAndUpdate`
* `findOneAndReplace`
* `findOneAndUpsert`
Passing `trustEmbeddedValue: true` will skip any additional mongodb requests for relations containig plain objects instead of identifiers. `projection` is still applied, though.
This logic has two important pitfalls:
* Some complex projections are not supported. Using `trustEmbeddedValue: true` with unsupported projection will cause an error to be thrown.
* Provided object is used "as is", which may result in saving outdated data. Missing fields are not fetched, but any fields not matching `projection` are dropped.