BuecherwurmAPI/Data/Repository.cs

using System;
using System.Collections.Generic;
using BuecherwurmAPI.Models;
using Microsoft.Data.Sqlite;

namespace BuecherwurmAPI.Data
{
    internal class Repository : IRepository
    {
        private SqliteConnection _dbConnection;

        public Repository()
        {
            var connectionBuilder = new SqliteConnectionStringBuilder {DataSource = "LongWormMemory.db"};
            _dbConnection = new SqliteConnection(connectionBuilder.ConnectionString);
            _dbConnection.Open();
        }

        public IEnumerable<Lend> GetAllLends()
        {
            var lends = new List<Lend>();

            // using automatically disposes the command after completion
            using (var command = _dbConnection.CreateCommand())
            {
                command.CommandText = @"SELECT * FROM Lends";
                var dataReader = command.ExecuteReader();
                
                while (dataReader.Read())
                {
                    var returned = (long) dataReader["Returned"] == 0;
                    
                    lends.Add(new Lend
                    {
                        Id = (long) dataReader["Id"],
                        Customer = (string) dataReader["Customer"],
                        ItemId = (long) dataReader["ItemId"],
                        Returned = !returned,
                        ReturnDate = DateTime.Parse((string)dataReader["ReturnDate"])
                    });
                }
            }
            return lends;
        }

        public Lend GetLendById(int id)
        {
            return new Lend{Id = 1, Customer = "Nek0", ItemId = 1337, Returned = false, ReturnDate = DateTime.Now};
        }
    }
}