EFE - Temporary Table - TemporaryTableName (EF Core)

CSharp · Console

/Program.cs

// Entity Framework Extensions
// Doc: https://entityframework-extensions.net/temporary-table#temporarytablename

// @nuget: Microsoft.EntityFrameworkCore.SqlServer
// @nuget: Z.EntityFramework.Extensions.EFCore

/*
## 🏷️ TemporaryTableName

Gets or sets the exact name to use for the temporary (or permanent) staging table.

If you provide a custom table name, you must also enable the option `TemporaryTableCreate = true;` if you want the library to **create** the table.

If you want the library to **create and drop** the table automatically afterward, you can simply use `TemporaryTableCreateAndDrop = true;`.


The name you choose determines the type of table that will be used:

* `"MyTemporaryTableName"` → uses a **permanent table**
* `"#MyTemporaryTableName"` → uses a **local temporary table**
* `"##MyTemporaryTableName"` → uses a **global temporary table**

You can use the string `{ZZZ_action}` in your name to have it automatically replaced by the current action (insert, update, delete, merge, synchronize).

### 💡 Why it can be useful

Using your own temporary table name can be very handy in different scenarios, such as:

* **Re-using the same table** across multiple operations instead of creating and dropping it every time.
* **Improving SQL query plan caching** since the optimizer can recognize the same table name and reuse execution plans.
* **Debugging and testing** by making the temporary table visible with a predictable name.
* **Coordinating across processes** (for example, with global temp tables) when different sessions need to share data.
*/

using System;
using System.Linq;
using System.Text;
using Microsoft.EntityFrameworkCore;
using System.Collections.Generic;
using Microsoft.Data.SqlClient;

public class Program
{
	public static void Main()
	{
		using (var context = new EntityContext())
		{
			context.Database.EnsureCreated();
			CacheSchemaToIgnoreInLog(context);
		}
		
		using (var context = new EntityContext())
		{
			// minimum 11 customers to use a temporary table
			var customers = GenerateCustomer(11);
		
			StringBuilder sb = new StringBuilder();
			
			context.BulkMerge(customers, options =>
			{			
				options.TemporaryTableName = "#MyTemporaryTableName_{ZZZ_action}";
				options.TemporaryTableCreateAndDrop = true;
				
				options.Log = s => sb.AppendLine(s);
			});
			
			Console.WriteLine(sb.ToString());
			
			FiddleHelper.WriteTable(context.Customers.AsNoTracking());
		}
	}
		 	
	public static List<Customer> GenerateCustomer(int max)
	{
		var list = new List<Customer>();
		for (int i = 0; i < max; i++)
		{
			list.Add(new Customer() { Name ="Customer_" + i});
		}
		
		return list;
	}
	
	public static void CacheSchemaToIgnoreInLog(EntityContext context)
	{
		var customers = GenerateCustomer(11);

		context.BulkInsert(customers, options => { options.IsReadOnly = true; });
	}

	public class EntityContext : DbContext
	{
		public EntityContext() 
		{
		}

		protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
		{
			optionsBuilder.UseSqlServer(new SqlConnection(FiddleHelper.GetConnectionStringSqlServer()));

			base.OnConfiguring(optionsBuilder);
		}
		
		public DbSet<Customer> Customers { get; set; }
	}
	
	
	public class Customer
	{
		public int CustomerID { get; set; }
		public string Name { get; set; }
		public Boolean IsActive { get; set; }
	}
}