Database Integration

This program demonstrates the usage of a Repository layer to insert and read data from a finance context.

It was developed in F# using:

• The SAFE stack for the backend (the web frontend is not used)
• EntityFramework to handle database access and Migrations
• PostgreSQL database

How the project is organized

Following the SAFE stack, it has three projects (Client, Server and Shared), but the Client is not being used here. I kept only the minimum code to keep it running. A console App is also provided to help test the application.

Code is organized as follows:

• The Shared project contains the API's definition and data types
• The Server project contains:
  • The API's implementation (for create, get and getAll endpoints)
  • The Repository that handles access to the database
  • The migrations file to init the database
• The Demo project contains a script to insert random items into the database and query items (all items or the items that match a criteria defined by the user)

How to run the server

• Clone this repository to your machine
• Set the database connection string:
  • For the sake of simplicity, it's defined as a string at DataAccess.fs
  • Fill the connectionString with your database info (it could be from a free provider, like www.elephantsql.com)
• Navigate to src/Server and run dotnet ef database update to run migrations and initialize the database
  • If this doesn't work, maybe you need to install the EntityFramework tools dotnet tool install --global dotnet-ef
• Before running the project for the first time, run dotnet tool restore from the project's root directory
• From the project's root directory, run dotnet fake build --target run to start the server
• To ensure that everything is running, go to http://localhost:8080 on a web browser. It should display an empty page with a random image as background

How to run the demo App

• Navigate to src/Demo and run dotnet run to start the demo console App
• From the console App, input the desired option:
  • 1 - To populate the database with 10 random rows (you can do this multiple times)
  • 2 - To query the database with a given criteria, as follows:
    • Input the UserId, StartDate, EndDate, MinPrice, MaxPrice, MinQuantity, MaxQuantity, Provider list and Pair list
    • There's an example in brackets [like this] of the expect input for each field
    • Each of these values will be used as a filter on the database query
    • To ignore a filter (for example, to get rows for all users), just type 0 or an empty string as indicated in the input prompt
    • Important: there's not much validations being performed here, so if an invalid input is inserted, the application will stop
  • 3 - To list all rows currently in the database
  • Anything else to quit