Is it possible to create a model where the relationships are dynamically generated by the application?
I saw the KeystoneJS project that does a nice job of defining the model (see: http://keystonejs.com/docs/database/#relationship-definitions)
But these need to be defined by node, I'm interested in creating these within the application. Are there any ORMs or framework projects that already do that? I I've seen frameworks like the MODxCMS that allow users to create additional fields, by putting everything from the custom (templatevar) values into one table. think mongodb would be great for setting this up without this single table approach.
Any idea how to go about setting this kind of system up? I'm not sure where to start.
I guess mongoose might help you here. And you may want to have a look at mongo-relation too.
Related
How would I allow my primary user to dynamically create forms they can issue to their end clients. Each of my primary users has their own unique information they would like to collect that I do not know before hand. I would like to avoid creating new models in code for their dynamic needs and then having to migrate the models.
I came across this which had an interesting response but it starts with disclaimer
The flexibility of Python and Django allow developers to dynamically create models to store and access data using Django’s ORM. But you need to be careful if you go down this road, especially if your models are set to change at runtime. This documentation will cover a number of things to consider when making use of runtime dynamic models.
Which leads me to believe a lot can go wrong.
However because I'm using wagtail I believe there is probably a way to use StructBlocks & StreamFields to accomplish it.
Any guidance would be helpful.
Wagtail provides a form builder module for this purpose.
I have two possible solutions for you, although it should be said that there is probably some library with Django that I don't know about that does this, but that being said.
Prompt your user for which fields they want and the field type.
Pass this as a dictionary to some function that would generate the HTML code for the form.
When this form is used, instead of worrying about storing the fields seperately, store a dictionary in the Models. There are two ways to do that here
Another way that you could do this, albeit more convoluted but more suited to your needs, is to use MongoDB for the database for Django instead. Because it is unstructured, it might be better suited for your use case. Instructions on using MongoDB for Django are here
I am using Knex.js to build SQL queries. It works well but I need to convert my query results into domain entities (a type representing an object from the domain) for my graphql resolvers. I used Knex to avoid using an ORM because a number of people online made it seem like an ORM will make queries more difficult. My current best idea is to follow the Repository pattern and have the ugly code for converting results to classes in the repo class. Better ideas are welcome :)
As I understood you want to just make a db-call based on GraphQL query (which is mean you already have db and want to use simple ORM instead of EF for example).
I don't know which platform do you have, but if you have .net, you can take a look NReco.GraphQL. It allows to set db-connection and define graphql schema in the json file (graphql schmea to db-table including relation between schemas), definately, it's worth take a look.
I removed a model fully from my app: deleted the model.js and model.json from models, deleted a relation in another model, and erased it from model-config.json.
However, the table created for the model, and the column in the other model remain in the DB (in all environments). I tried auto-migrating, but they're still there.
Do I need to manually go through all databases and drop the table and column manually, or can I tell LB to pick up the changes on its own somehow?
Do I need to manually go through all databases and drop the table and column manually, or can I tell LB to pick up the changes on its own somehow?
LoopBack is not able to detect which models were removed and drop the corresponding database tables.
As you have discovered yourself, the solution is to go through the databases and drop the tables manually.
BTW I don't recommend using LoopBack's autoupdate/automigrate functionality in production and highly advocate for maintaining a set of migration scripts as described e.g. in Martin Fowler's excellent article Evolutionary Database Design.
LoopBack does not support migration scripts yet, but we are discussing how to implement them for LoopBack 4+, see https://github.com/strongloop/loopback-next/issues/487
Have you looked into using the built-in API?
https://apidocs.strongloop.com/loopback/#app-deletemodelbyname
Ended up doing it manually - in 3 databases :(
I'm closing the question, but willing to reopen if someone had a good answer.
Hullo,
I have a crux to bear with Mongoose.
Is there a way of using JSON-Shema with Mongoose Schemas?
Say I want to define my API data schema using a standard like JSON-Schema, because it's nice.
It seems like I need to define it again when I want to use Mongoose / MongoDB!
That's quite some ugly duplication I like to avoid. Ideally, changing the JSON-Schema definition would also change the MongoDB schema.
A similar problem would appear if I would use JOI.JS validation library.
Has anyone found a solution to that?
Or is there an alternative approach?
thanks
Try this library: https://www.npmjs.com/package/json-schema-to-mongoose There are others out there too. I created json-schema-to-mongoose since the other libraries didn't quite fit my needs.
Also, I like to generate the json-schema from TypeScript using Typson. It makes it so the json-schema is more statically typed.
Update
It appears the Typson project is dead. Here's another (typescript-json-schema) project which does the same thing, although I've never used it.
Chiming in here since I've also run into this problem and found a solution that is alternative to the suggestions provided.
One can use https://github.com/nijikokun/generate-schema to take a plain JS object and convert it to both JSON Schema and a Mongoose Schema. I find this tool to be easier in the case of retrofitting existing code with validation and persistence since you will likely already have an example object to start with.
I'm not sure how to put this right.
I need to use yii to create an application which needs to use objects and fields.
Let's say that in my app I want to have those three objects: Computers, Servers, IPs. Each of these three objects will have it's own attributes:
Computer: CPU, Motherboard, Video adapter, IP (related to the object IP), Aquisition Date
Servers: Name, IP (related to object IP), etc...
IP: IP Address.
As you can see I also need a way to link my objects between them.
Every kind of attribute (object field) must be treated in it's own way, after it's own type. For example, we have a field called CPU which can be in a list of values. We have Aquisition Date and it must be treated like a date.
Well, the problem is that I need an extension to help me in creating those object types and setting their attributes. I don't know how to search for something appropriate.
Implementing this functionalities will take me a lot of time which I don't have right now. If there are no extensions, do you have any solution to implement one? I have some ideas for creating classes for every user field, classes which will implement an interface that render the methods properly for insert, update, etc.
Thank you!
You don't need any extension if you use Yii. You'd rather yake some time to read the tutorials. My advice is to begin with Larry Ullman's Learning Yii Series and then to go to the Definitive Guide
Once you have set your database and build your tables, you will only have to activate the Gii component of Yii framework and to use it's automated code generators to build your basic models, views and controllers.
The only thing you've left will be customization, of course. Yii + Gii save you all the repetitive work. But... read the docs.
[EDIT] after the OP comment below.
Is it an EAV model that you are looking for ? There is an unofficial Yii extension dealing with that : EAV Behavior. I have no idea whether it's good or not, as I definitely avoid to work with EAV databases. Let us know your opinion if you try to use it.