'How to query data from different types of databases in a microservice based architecture?
We are a using a micro-service based pattern for our project where we have Users and their Orders. Users personal information (name, email, mobile) is stored in User table in relational database while we are storing Orders data of users in Orders collection in NoSql database. We want to develop an API to get a paginated list of all the orders placed with order details along with finer details of user associated like - user name, mobile, email along with each order. We are storing userId in Orders collection. The problem is how do we get User details for each order in this list since both the resources are in different databases. We also thought of storing user name, email and mobile in Orders collection only but what if a user updates their profile, the Orders collection will have stale user data.
What is the best approach to address this issue?
Solution 1:[1]
You can use API gateway pattern, UI will call to API gateway endpoint and the Endpoint will call the both the API/services to get the result and aggregate it then returns aggregated response to the UI (caller)
Solution 2:[2]
Well it mostly depends on scalability needs in terms of data size and number of requests. You may go with the API gateway if you don't have too much data and you don't get many requests to that service.
Otherwise if you really need something scalable then you should implement your own thought with an event based communication.
I already provided an answer for a similar situation you can take a look https://stackoverflow.com/a/63957775/3719412
Solution 3:[3]
You have two services Orders and Users. You are requesting Orders service to get all Orders. It will return a response data which will contains ID of Users (each Order contains ID of User). Then, you will make a request to a Users service to get an information regarding User by ID which you got before. And finally, you can aggregate those results (if it is needed).
As guys mention, good solution will be to implement API Gateway here. As a client, you will send a request to a single port with endpoint (to a Gateway) and Gateway should create logic which I have described before.
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | |
| Solution 2 | cool |
| Solution 3 | Serhii Zhura |