I'm not sure whether the auto generated id (object_id) of mongodb is unique across all the document or not. I've a dilemma about referencing.
Says I have a system which multiple users can create their own products and categories. So I will have product collection and category collection.
To get a category of a product, should I get the category by using user id and product id or product id alone is enough? since I will first get the product id using user id before I can find the category of that particular product.
Related
I am currently trying to model a MongoDB database structure where the entities are very complex in relation to each other.
In my current collections, MongoDB queries are difficult or impossible to put into a single aggregation. Incidentally, I'm not a database specialist and have been working with MongoDB for only about half a year.
To keep it as simple as possible but necessary, this is my challenge:
I have newspaper articles that contain simple keywords, works (oevres, books, movies), persons and linked combinations of works and persons. In addition, the same people appear under different names in different articles.
Later, on the person view I want to show the following:
the links of the person with name and work and the respective articles
the articles in which the person appears without a work (by name)
the other keywords that are still in the article
In my structure I want to avoid that entities such as people occur multiple times. So these are my current collections:
Article
id
title
keywordRelations
KeywordRelation
id
type (single or combination)
simpleKeywordId (optional)
personNameConnectionIds (optional)
workIds (optional)
SimpleKeyword
id
value
PersonNameConnection
id
personId
nameInArticleId
Person
id
firstname
lastname
NameInArticle
id
name
type (e.g. abbreviation, synonyme)
Work
id
title
To meet the requirements, I would always have to create queries that range over 3 to 4 tables. Is that possible and useful with MongoDB?
Or is there an easier way and structure to achieve that?
I have two different collection, customer and prospect. _Id(customer collection) is presented in prospect collection with the name of customerId.. Now I want to get the customer details based on the customerid. how to achieve it
db.getCollection('st_salesquotes').find({CustomerId:'5a66f2549ca9b27c4df31e62'})
I want to display the customers who are all present in salesquote based on the _id(customer collection)
Suppose I have following 4 collections:
1- posts
2- companies
3- groups
4- users
Bellow is my current structure in post:
and their relation is:
A company has an owner and many other members (user collection).
A group has many members (users).
A user has many posts.
A group has many posts that published by one of its members.
A company has many posts that published by its owner or members.
Now i have a problem on storing relation of users, company, and group with posts collection.
Bellow is my current structure:
I have decided to have a field postable inside my post document, and has a type field that will be 'user', or 'group', or 'company', and two other fields name, and id that will be company/group id and company/group name in cases that post is belonged to company or group but not user means type="group" || type="company".
Now how i can handle this to map id as FK of group and company collection (one field FK of two collection) ?
Is it the right structure ?
What you have here is a polymorphic association. In relational databases, it is commonly implemented with two fields, postable_id and postable_type. The type column defines which table to query and id column determines the record.
You can do the same in mongodb (in fact, that is what you came up with, minus the naming convention). But mongodb has a special field type precisely for this type of situations: DBRef. Basically, it's an upgraded id field. It carries not only the id, but also collection name (and database name).
how i can handle this to map id as FK of group and company collection (one field FK of two collection)?
Considering that mongodb doesn't have joins and you have to load all references manually, I don't see how this is any different from a regular FK field. Just the collection name is stored in the type field now, instead of being hardcoded.
Creating a product set requires associating a product_catalog_id:
POST https://graph.facebook.com/<API_VERSION>/<PRODUCT_CATALOG_ID>/product_sets
Reading an product set having the Facebook id is easy:
GET https://graph.facebook.com/<API_VERSION>/<PRODUCT_SET_ID>
Unfortunately, the response for that request contains 3 fields (id, name and filter).
How can I get the product_catalog_id associated to a product set (if I know the product_set_id)?
PS: The documentation does not help with that: https://developers.facebook.com/docs/marketing-api/dynamic-product-ads/product-catalog#productset
The catalog ID is not a field of the product set, so you therefore cannot traverse the graph in this way.
The only way to gather this associated is to read read the catalogues in a business, and their product sets to find the correct association unfortunately.
I'm pretty new to Mongo. Just started a project using Mongodb as the database.
I'm not sure how should i design the following use-case to a document base database.
User-Case
1. Vendor/Distributor has a list of product on our system.
2. There's a standard price list of each product for any customers.
3. Vendor/Distributor also has customize price list of each of the product for each customer.
eg. CustA have a productA at different pricing from the standard and it's only available to him.
4. Some of the Product are only available through customize price, and I match those product with attribute public = false.
How should i work this out in document base database?
Current design i have is.
1. [Product Document] with embedded document of standard price list.
2. [Product_Price Document] with oneToMany link [Product Document] and oneToMany to [Customer Document]
3. [Customer Document].
With this Model, I'm facing problem with querying by paging.
Example I query the first 30 Product sorted by name. Then query [Product_Price Document] with the 30 ProductId that match, so that I have those customize price for that customer who login.
The problems come where by I couldn't query item that are customize to the user that is not available for everyone.
Is there a better way or design the schema or what should i do with the query?
I'm using PHP, Doctrine2, Symfony2
When you query the Product_Price_Document query it using both ProductID and current CustomerID. Or am I missing something?
Here's how I would structure it.
Have two collections:
- Products
- Vendors
Your products table would have the list of all your products and their standard price. Your vendors page would have an array of product ID's along with an override price in the case that they have a different price for that particular product.
If you are also tracking customers then you could make that a collection too and have a belongs to relationship almost to the vendors.
so in short:
collection.vendor:
{"name":'foo',"products":[{"_id":mongoId,"priceOveride":15.50},..]}
collection.products:
{"name":"bar","price":15.40}
Excellent resource for reading a bit more into the relationships which you can use:
Learn Mongo Interactively