davepcallan’s gists

davepcallan / HotelBookingTemplate.cs

Created January 3, 2025 09:03

Template Method Pattern C# simple example

	public abstract class HotelBookingTemplate
	{
	// Template Method
	public void BookRoom()
	{
	SelectRoom();
	ProcessPayment();
	ApplyDiscount();
	SendBookingConfirmation();
	}

davepcallan / Program.cs

Created January 3, 2025 08:42

.NET Rate limiting simple examples

	using Microsoft.AspNetCore.RateLimiting;
	using System.Threading.RateLimiting;

	var builder = WebApplication.CreateBuilder(args);

	builder.Services.AddRateLimiter(options =>
	{
	// 1. Fixed Window Limiter (20 requests per 2 minutes)
	// -----------------------------------------------
	// \|----------------- 2 min -----------------\|

davepcallan / SlowQueryInterceptor.cs

Last active November 25, 2025 15:54

Finding slow queries with Entity Framework Interceptors

	using Microsoft.EntityFrameworkCore.Diagnostics;
	using System.Data.Common;

	namespace EntityFrameworkExamples;

	public class SlowQueryInterceptor(ILogger<SlowQueryInterceptor> logger) : DbCommandInterceptor
	{
	private const int _slowQueryThresholdInMilliseconds = 5; //from config

	public override DbDataReader ReaderExecuted(

davepcallan / CreateOrder.cs

Last active December 18, 2024 00:15

Vertical Slice Architecture example - UseCases -> CreateOrder.cs

	// 1. Order Entity
	namespace VerticalSliceExample.Domain;

	public class Order
	{
	public int Id { get; set; }
	public int CustomerId { get; set; }
	public Dictionary<int, int> Products { get; set; } = new(); // ProductId -> Quantity
	public decimal TotalAmount { get; private set; }
	public DateTime CreatedAt { get; set; } = DateTime.UtcNow;

davepcallan / CountByDotnet9.cs

Created November 30, 2024 15:50

.NET 9 new LINQ CountBy compared to existing approaches benchmarks

	using BenchmarkDotNet.Attributes;
	using BenchmarkDotNet.Columns;
	using BenchmarkDotNet.Configs;
	using BenchmarkDotNet.Environments;
	using BenchmarkDotNet.Jobs;
	using BenchmarkDotNet.Reports;
	using System;
	using System.Collections.Generic;
	using System.Linq;

davepcallan / FindSparseColumnCandidates.sql

Created May 11, 2024 10:24

SQL Server SQL script to find sparse column candidates

	USE TestDB
	GO

	DECLARE @DatabaseName VARCHAR(100)
	DECLARE @SchemaName VARCHAR(100)
	DECLARE @TableName VARCHAR(100)
	DECLARE @ColumnName VARCHAR(100)
	DECLARE @FullyQualifiedTableName VARCHAR(500)

	--Create Temp Table to Save Results

davepcallan / AddColumnIfNotExists.sql

Created May 7, 2024 16:20

Add created_date column to all tables which don't have it already in SQL Server

	SELECT 'ALTER TABLE ' + QUOTENAME(ss.name) + '.' + QUOTENAME(st.name) + ' ADD created_date DATETIME NULL;'
	FROM sys.tables st
	INNER JOIN sys.schemas ss on st.[schema_id] = ss.[schema_id]
	WHERE st.is_ms_shipped = 0
	AND NOT EXISTS (
	SELECT 1
	FROM sys.columns sc
	WHERE sc.[object_id] = st.[object_id]
	AND sc.name = 'created_date'
	)

davepcallan / userInfo.graphql

Created April 25, 2024 15:30

Example query of how to get user information from the GitHub graphql API

davepcallan / ExceptionHandlingDotnet9.cs

Created April 11, 2024 18:56

Exception Handling .NET 9 v .NET 8

	using BenchmarkDotNet.Attributes;
	using BenchmarkDotNet.Columns;
	using BenchmarkDotNet.Configs;
	using BenchmarkDotNet.Jobs;
	using BenchmarkDotNet.Reports;
	using BenchmarkDotNet.Environments;

	namespace ExceptionBenchmark
	{
	[Config(typeof(Config))]

davepcallan / SQLServerTruncateRollbackExample.sql

Created April 5, 2024 16:43

Sample SQL which shows rollback IS possible in SQL Server

	-- Create Test Table
	CREATE TABLE TruncateTest (ID INT)
	INSERT INTO TruncateTest (ID)
	SELECT 1
	UNION ALL
	SELECT 2
	UNION ALL
	SELECT 3
	GO
	-- Check the data before truncate

Dave Callan davepcallan