Use sequential IDs for support task references

Author: gunndabad

TeachingRecordSystem/src/TeachingRecordSystem.AuthorizeAccess/Pages/CheckAnswers.cshtml.cs

@@ -2,7 +2,6 @@
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Microsoft.AspNetCore.Mvc.RazorPages;
-using Npgsql;
 using TeachingRecordSystem.Core.DataStore.Postgres;
 using TeachingRecordSystem.Core.DataStore.Postgres.Models;
 using TeachingRecordSystem.Core.Models.SupportTasks;
@@ -36,7 +35,6 @@ public async Task<IActionResult> OnPostAsync()
 
         var supportTask = new SupportTask()
         {
-            SupportTaskReference = SupportTask.GenerateSupportTaskReference(),
             CreatedOn = clock.UtcNow,
             UpdatedOn = clock.UtcNow,
             SupportTaskType = SupportTaskType.ConnectOneLoginUser,
@@ -65,19 +63,7 @@ await dbContext.AddEventAndBroadcastAsync(new LegacyEvents.SupportTaskCreatedEve
             SupportTask = EventModels.SupportTask.FromModel(supportTask)
         });
 
-        while (true)
-        {
-            try
-            {
-                await dbContext.SaveChangesAsync();
-                break;
-            }
-            catch (Exception ex) when (ex.InnerException is PostgresException postgresException && postgresException.SqlState == PostgresErrorCodes.UniqueViolation)
-            {
-                supportTask.SupportTaskReference = SupportTask.GenerateSupportTaskReference();
-                continue;
-            }
-        }
+        await dbContext.SaveChangesAsync();
 
         await JourneyInstance.UpdateStateAsync(state => state.HasPendingSupportRequest = true);
 

TeachingRecordSystem/src/TeachingRecordSystem.Core/DataStore/Postgres/Mappings/SupportTaskMapping.cs

@@ -12,7 +12,7 @@ public void Configure(EntityTypeBuilder<SupportTask> builder)
         builder.ToTable("support_tasks");
         builder.HasKey(p => p.SupportTaskReference);
         builder.HasQueryFilter(q => EF.Property<DateTime?>(q, nameof(SupportTask.DeletedOn)) == null);
-        builder.Property(p => p.SupportTaskReference).HasMaxLength(16);
+        builder.Property(p => p.SupportTaskReference).HasMaxLength(16).HasDefaultValueSql("'TRS-' || nextval('support_task_reference')::text");
         builder.HasOne(t => t.Person).WithMany().HasForeignKey(p => p.PersonId).HasConstraintName("fk_support_tasks_person");
         builder.HasIndex(t => t.OneLoginUserSubject);
         builder.HasIndex(t => t.PersonId);