From 001e78736ccad3858f8108f7b7ae5197b6f007cd Mon Sep 17 00:00:00 2001
From: Kevin Matsubara <kevin.matsubara@proton.me>
Date: Tue, 8 Apr 2025 22:35:20 +0200
Subject: [PATCH] Add example user-defined function.

---
 EntityFrameworkCore.Console/Program.cs            | 15 +++++++++++++++
 .../DeadBallZoneLeagueDbContext.cs                | 11 +++++++++++
 2 files changed, 26 insertions(+)

diff --git a/EntityFrameworkCore.Console/Program.cs b/EntityFrameworkCore.Console/Program.cs
index e9552a6..50bcd48 100644
--- a/EntityFrameworkCore.Console/Program.cs
+++ b/EntityFrameworkCore.Console/Program.cs
@@ -17,6 +17,21 @@ context.Database.EnsureCreated();
 // var firstCoach = await context.Coaches.FirstOrDefaultAsync();
 
 
+async Task UserDefinedQuery()
+{
+  var earliestMatch = context.GetEarliestTeamMatch(1);
+  // This is done, if you have a user-defined function in the database.
+  // for example:
+  // CREATE FUNCTION [dbo].[GetEarliestMatch] (@teamId int)
+  //   RETURNS datetime
+  //   BEGIN
+  //     DECLARE @result datetime
+  //     SELECT TOP 1 @result = date
+  //     FROM MATCHES [dbo].[Matches]
+  //     ORDER BY Date
+  //     return @result
+  //   END
+}
 
 async Task QueryScalarType()
 {
diff --git a/EntityFrameworkCore.Data/DeadBallZoneLeagueDbContext.cs b/EntityFrameworkCore.Data/DeadBallZoneLeagueDbContext.cs
index d539fa9..f8dc8dc 100644
--- a/EntityFrameworkCore.Data/DeadBallZoneLeagueDbContext.cs
+++ b/EntityFrameworkCore.Data/DeadBallZoneLeagueDbContext.cs
@@ -41,5 +41,16 @@ public class DeadBallZoneLeagueDbContext : DbContext
 
     // This database object does not have a Primary Key, so we state that here, otherwise an exception is thrown.
     modelBuilder.Entity<TeamsAndLeaguesView>().HasNoKey().ToView("vw_TeamsAndLeagues");
+
+    // This is for user-defined functions.
+    modelBuilder.HasDbFunction(
+      typeof(DeadBallZoneLeagueDbContext)
+      .GetMethod(
+        nameof(GetEarliestTeamMatch),
+        new[] {typeof(int)}
+      ))
+      .HasName("GetEarliestMatch");
   }
+
+  public DateTime GetEarliestTeamMatch(int teamId) => throw new NotImplementedException();
 }