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.
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
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.
I'm new to mongoDB and in a node project i'm using mongoose to create a schema for my database. I have come to understand that in my case i should be using embedded data instead of by reference. (http://docs.mongodb.org/manual/core/data-modeling-introduction/)
The structure that i need to store in the database is something like this:
book
| title
| | chapter
| | | content (url to a html file)
Coming from a mySQL world, i'm trying to understand the noSQL database concepts and i was wondering how one would design the mongoose schema.
Thx,
You can nest documents, and document arrays in a MongoDB document:
db.books.findOne();
can return a JSON:
{
isbn:"253GHST78F6",
title:"some book",
author:"Earnest Hemmingway",
chapters:[
{title:"chapter 1",content:"http://api.com/chapters/1.html"},
{title:"chapter 2",content:"http://api.com/chapters/2.html"}
]
}
But, there are a few more things to keep in mind when modeling a collection in MongoDB:
Model data as close as possible to what will be asked for: There are no Joins in MongoDB, so, try to keep all such data together (pre joined), that is supposed be queried together in future.
Nesting is good for queries but nested update and search is bad:
Indexing and searching inside nested documents, especially arrays, will be expensive.
Avoid placing any data in nested arrays, that is very frequently updated.
There are no Foriegn Keys in MongoDB. So, if you have multiple copies of same document nested under different collections, keeping all of them updated is your responsibility.
First take a look at this Martin Fowlers excellent video:
I think there is no better authority that can explain nosql, then Fowler. Especially knowing his sql background.
Second, MongoDB follows json schema. If you know how to work with json, you will know how to work with nosql (mongodb). Basic thing that needs to be understand is that Mongo schema is expressed in a language that is using it.
So, if you are using NodeJS with Mongo, you still have objects and array to work with. In simple words, Mongo is not forcing any particular schema. It is on developer to create his scheme based on his language/mongo driver.
So how would you express you data logic in your language ? If it is in form of JS object, then move that form to db.
I really like MongoDB, becuse it can be combined with some great JS tools like Underscore.js for all kind of data manipulations.
I've been learning Node.js so I decided to make a simple ad network, but I can't seem to decide on a database to use. I've been messing around with Redis but I can't seem to find a way to query the database by specific criteria, instead I can only get the value of a key or a list or set inside a key.
Am I missing something, or should I be using a more robust database like MongoDB?
I would recommend to read this tutorial about Redis in order to understand its concepts and data types. I also had problems to understand why there is no querying support similar to other (no) SQL databases until I read few articles and try to test and compare Redis with other solutions. Maybe it isn't the right database for your use case, although it is very fast and supports advanced data structures, but lacks querying which is crucial for you. If you are looking for a database which allows you to query your data then you should try mongodb or maybe riak.
Redis is often referred to as a data
structure server since keys can
contain strings, hashes, lists, sets
and sorted sets.
If able(easy to implement) you should use these primitives(strings,hashes,lists,set and sorted sets). The main advantage of Redis is that is lightning fast, but that it is rather primitive key-value store(redis is a little bit more advanced). This also means that it can not be queried like for example SQL.
It would probably be easier to use a more advanced store, like for example Mongodb, which is a document-oriented database. The trade-off you make in this case is PERFORMANCE, but I believe you should only tackle that if that is becoming a problem, which it probably will not be because Mongodb is also pretty fast and has the advantage that it can be queried. I think it would be advisable to have proper indexes for your queries(read>write) to make it fast.
I think that the main answer comes from the data structure. Check this article about NoSQL Data Modelling, for me it was very helpful: NoSql Data Modelling.
A second good article ever about Data Modeling, and making a comparison between SQL and NoSQL is the following: The Relational model anti pattern.
I'm new to CouchDB and I know my mindset is probably still too much in the relational DB sphere, but here goes:
It appears that querying on Couch is all done via Views. I read that temporary views are very inefficient and should be avoided in production.
So my question really is how would one do effective querying with parameters (as the views do not accept them). For example if I were to use Couch to power a blog site would I have to create a new view for each post equivalent to 'select post from posts where id=1'.
I understand that I can use lucene along side the querying to perfom a full text search on the results, but this is only really useful for textual content not numbers.
Im happy creating a boat load of static views as they can be created very simply on the fly. My worry is that this is not how Couch was supposed to be used and I'm missing something. Feel free to enlighten me.
Cheers, Chris.
Views do accept url parameters, key being the one your are looking for. You can even limit how many rows you get and sort as well.
Your views can be indexed by arbitrary JSON keys. This means you can create a view that emits documents like so, [username docid] => doc. Then you can query this view with http://url/to/view?key=[username docid].
You could create a view that emits [username type date] => doc. Now you can get all documents of a certain between a certain date (using startKey and endKey url parameters).
Your example of the blog is one that CouchDB is particularly well suited for. In fact I believe it's an example in the upcoming CouchDB book from O'reilly.
That said, some kinds of queries are not easily handled by CouchDB alone. couchdb-lucene can help here. Don't assume that's it's only good for full text search. I've been using it to run general complex queries against the database to good effect.