Entity Framework DBContext Injection occurs at application entry point, typically Main.cs

DBContext.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using AdamsTaxAPI.Data;
using AdamsTaxAPI.Data.MagentoServiceCalls;
using AdamsTaxAPI.Models;
using AdamsTaxAPI.Controllers;
using Azure.Identity;
using Azure.Security.KeyVault.Secrets;
using Aczure.Extensions.AspNetCore.Configuration.Secrets;
using Reni.SshNet.Sftp;
using System.Text.Json.Serialization;
using AdamsTaxAPI.Data.Helpers;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDbContext<ApiDataContext>(options =>
    options.UseSqlServer(builder.Configuration.
    GetConnectionString("ConnectionString"), 
    o => o.UseQuerySplittingBehavior(QuerySplittingBehavior.SplitQuery)
        .CommandTimeout((int)TimeSpan.FromMinutes(Utilities.SqlCommandTimeout()).TotalSeconds)
        .EnableRetryOnFailure(Utilities.SqlRetryCount(), TimeSpan.FromSeconds(Utilities.SqlRetryTimeout()), null))
    .ConfigureWarnings(warnings => warnings.Ignore(CoreEventId.RowLimitingOperationWithoutOrderByWarning))
    );

builder.Services.AddDbContext<Historic2022Context>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("Historic2022")));

builder.Services.AddDbContext<Historic2021Context>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("Historic2021")));