I have a microservice endpoint that gets a list of company details from the DB. The URL pattern looks like this.
GET https://example.com/api/v1/companies
I need to develop another URL that fetches only the company names from DB. I understand I can reuse the same URL, but to fetch only one column i don't want to fetch all columns.
Please guide me how to have the url pattern for this case.
Ex: GET https://example.com/api/v1/companies/companyNames?
We should not increase number of services exposed until it is really needed. I will recommend re-using the same service with format:
GET https://example.com/api/v1/companies?col=name
If col parameter is blank you can assume to return all columns. This will help you re-use the codebase; minimal changes; and lots of flexibility in future; and less confusion for end consumer.
Related
All,
I am building a Power Flow. I am returning an object that has a relationship to another entity.
I want to get some values from the related entity.
I am attemping to use the "Get Record" connector. The returning object returns just the logicalEntityName (in this case "opportunities") but Get Record wants an Entity Name that is the Schema Name ("Working Opportunities").
Big Question: What's the secret to use CDS to get information from a related record in another object?
Little Question: How do I do get the Schema Name?
The logical name will be the same as schema name except some casing difference, ie schema name will have camel casing (first letter of first/second word with capitals, you can notice it clearly in custom entity which will have publisher prefix like new_entityname) and logical name will have pascal casing (all lower case).
You can find the details in XrmToolBox metadata browser or in Solution.
In the below snip, (Logical) Name = Opportunity and Schema Name = Opportunity, also Display Name can be anything and can be changed anytime.
Regarding the related entities, you should use List Records: GetItems_V2 and you can use filter by passing parent record to get related child records. Read more
Could you please share flow screenshot and response to help you with your requirement?
As suggested by Arun you could use List Record and filter query to pass parent record id which will be available from dynamic content.
see below link.
https://crmkeeper.com/2019/08/31/cds-list-records-filter-query-using-flow/
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I was reading this article and it used the following query:
{
getAuthor(id: 5){
name
posts {
title
author {
name # this will be the same as the name above
}
}
}
}
Which was parsed and turned into an AST like the one below:
Clearly it is bringing back redundant information (the Author's name is asked for twice), so I was wondering how GraphQL Handles that. Does it redundantly fetch that information? Is the diagram a proper depiction of the actual AST?
Any insight into the query parsing and execution process relevant to this would be appreciated, thanks.
Edit: I know this may vary depending on the actual implementation of the GraphQl server, but I was wondering what the standard / best practice was.
Yes, GraphQL may fetch the same information multiple times in this scenario. GraphQL does not memoize the resolver function, so even if it is called with the same arguments and the same parent value, it will still run again.
This is a fairly common problem when working with databases in GraphQL. The most common solution is to utilize DataLoader, which not only batches your database requests, but also provides a cache for those requests for the duration of the GraphQL request. This way, even if a particular record is requested multiple times, it will only be fetched from the database once.
The alternative (albeit more complicated) approach is to compose a single database query based on the requested fields that executes at the root level. For example, our resolver for getAuthor could constructor a single query that would return the author, their posts and each of that post's author. With this approach, we can skip writing resolvers for the posts field on the Author type or the author field on the Post type and just utilize the default resolver behavior. However, in order to do this and avoid overfetching, we have to parse the GraphQL request inside the getAuthor resolver in order to determine which fields were requested and should therefore be included in our database query.
I'm upgrading an old procedural site to laravel 5.2, and I'm struggling with the old routes I made.
On this website, the routes were made like this : {user_slug}/{content_slug}.html. For the moment, I use cviebrock/eloquent-sluggable to generate the slugs, but I'm open to another one if this one cannot meet my needs.
I have two questions :
Can I make the content-slug unique, but per user ?
How can I write the route and the controller in order to match the correct user slug ad the correct content slug ?
I have not done this myself but I believe there would be a way in the validation rules to do this. Here is an untested rough draft to check content_slug in the posts table but only check uniqueness where the user_id field equals a variable:
'content_slug' => "unique:posts,content_slug,NULL,id,user_id,$user->id"
Depending on who you ask, they may advise you (either instead of or as well as doing the above) to set up a key in the database based on the user_id and content_slug fields. This way the database returns an error if an insert is attempted as well as gives a performance boost when running a query off that index. Queries off of an index can literally give an exponential performance increase.
I implementing RESTful API service and i have a question about saving related records.
For example i have users table and related user_emails table. User emails should be unique.
On client side i have a form with user data fields and a number of user_email fields (user can add any number of fields independently). When the user saves the form i must first make query to create record in users table to get her ID, and only then i can make query to save user emails (because in now i have id of record which come with response after saving user data). But if user enters not unique email in any field then the request will fail. So I create a record in the users table but not create record in user_emails table.
What are the approaches to implement validation of all this data before saving?
This is nor related restful api but transactional processing on the backend. If you are using Java, with JPA you can persist both element in the same transaction then you can notice if there is a problem and rollback the entire transaction returning a response.
I would condense it down to a single request, if you could. Just for performance's sake, if nothing else. Use the user_email as your key, and have the request return some sort of status result: if the user_email is unique, it'll respond with a success message. Otherwise, it'd indicate failure.
It's much better to implement that check solely on the server side and not both with the ID value unless you need to. It'll offer better performance to do that, and it'll let you change your implementation later more easily.
As for the actual code you use, since I'm not one hundred percent on what you're actually asking, you could use a MERGE if you're using SQL Server. That'd make it a bit easier to import the user's email and let the database worry about duplicates.
i am building my the model using ODataModelBuilder, i am trying to create navigation property however in the metadata i dont see any foreginkey indication, in my solution i am not using EF, so there is no foreignKey attribute, is it possible to add it by code?
As you clarified in your comment, the reason you want to add foreign key information is because your client application is not including related entities when you query the main entity. I don't think foreign keys are the problem here.
As an example, I'll use two entity types: Customer and Order. Every Customer has some number of associated Orders, so I have a navigation property on Customer called Orders that points to a collection of Orders. If I issue a GET request to /MyService.svc/Customers(1), the server will respond with all of the Customer's information as well as URLs that point to the related Order entities*. I won't, by default, get the data of each related Order within the same payload.
If you want a request to Customers(1) to include all of the data of its associated Orders, you would add the $expand query option to the request URI: /MyService.svc/Customers(1)?$expand=Orders. Using the WCF Data Services client (DataServiceContext), you can do this with .Expand():
DataServiceQuery<Customer> query = context.Customers.Expand("Orders");
However, WebAPI OData doesn't currently support $expand (the latest nightly builds do though, so this will change soon).
The other approach would be to make a separate request to fill in the missing Order data. You can use the LoadProperty() method to do this:
context.LoadProperty(customer, "Orders");
The LoadProperty approach should work with WebAPI as it stands today.
I know this doesn't answer your original question, but I hope addresses your intent.
*In JSON, which is the default format for WebAPI OData services, no links will show up on the wire, but they are still there "in spirit". The client is expected to be able to compute them on its own, which the WCF Data Services Client does.