Options Layering API's on Data Sources - Micrososervices kind of

Hasura takes data sources such as SQL, Postgress & MySQL and converts it into GraphQL API's.  SQL Server is in preview.  Service is available on Azure and hooks into AAD and AAD B2C.  Hasuru looks extremely interesting and useful.  Potentially a great time saver.

CDS/DataFelx/Oakdale - Allows for Entity creation and provides REST API's.

SharePoint lists provide HTTP API's for CRUD operations.

REST API's vs GraphQL

OpenAPI specification (previously known as the Swagger specification) is my default for an API, this allows for a known RESTful API that anyone with access can use.   Open API has set contracts that returned defined objects which is great, you can work with the API like a database with simple CRUD operations as defined by the specification.  The issue is that the returned objects are fixed in structure so you may need 2 or more queries to get the data you are looking for.  Alternatively, GrapghQL allows the developer to ask for the data exactly as the want it.

Open API example:

/api/user/{2} returns the user object  // Get the user object for user 2

/api/users/{2}/orders/10  // Returns the last 10 orders for the user

GraphQL example:

Post a single HTTP request.

query {

 User(id: "") {

    name

    email

    orders(last: 10 {

      orderid

      totalamount

      datemodified

    }

 }

} 

Database Option Notes:

PostgreSQL - Hybrid relation database (Communitity edition free, standard and enterprise higher loads) sits on Linex but can also use Windows OS.  Replicas are used for additional read-only nodes (I think up to 5 geo relicas allowed) 

Can be hosted on Azure or AWS IaaS.  PostgreSQL is also offered as a fully managed service (PaaS) on Azure (either single server or hyperscale).

MariaDB community fork off MySQL - Open source relation database used in the LAMP app stack.  Azure MySQL manage service can have up to 5 replicas for read heavy workloads.