修复MySQL问题

src/Jiaowu.Api/Infrastructure/Exams/ExamArrangementService.cs

@@ -230,12 +230,14 @@ public sealed class ExamArrangementService(AppDbContext db)
         foreach (var id in dbBusyIds) busyTeacherIds.Add(id);
         foreach (var id in excludeTeacherIds) busyTeacherIds.Add(id);
 
-        return await db.Teachers.AsNoTracking()
+        var candidates = await InvigilatorCandidateQuery
-            .Where(x => x.Status == TeacherStatus.Active)
+            .Create(db, busyTeacherIds)
-            .WhereNotIn(busyTeacherIds, x => x.Id)
-            .OrderBy(x => Guid.NewGuid())
-            .Take(needed)
             .ToListAsync(cancellationToken);
+
+        return candidates
+            .OrderBy(_ => Random.Shared.Next())
+            .Take(needed)
+            .ToList();
     }
 }
 

src/Jiaowu.Api/Infrastructure/Exams/InvigilatorCandidateQuery.cs

@@ -0,0 +1,15 @@
+using Jiaowu.Api.Domain.Academic;
+using Jiaowu.Api.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore;
+
+namespace Jiaowu.Api.Infrastructure.Exams;
+
+internal static class InvigilatorCandidateQuery
+{
+    public static IQueryable<Teacher> Create(
+        AppDbContext db,
+        IEnumerable<Guid> excludedTeacherIds) =>
+        db.Teachers.AsNoTracking()
+            .Where(x => x.Status == TeacherStatus.Active)
+            .WhereNotIn(excludedTeacherIds, x => x.Id);
+}

src/Jiaowu.Api/Infrastructure/Exams/MakeupExamArrangementService.cs

@@ -225,11 +225,13 @@ public sealed class MakeupExamArrangementService(AppDbContext db)
         foreach (var id in dbBusyIds) busyTeacherIds.Add(id);
         foreach (var id in excludeTeacherIds) busyTeacherIds.Add(id);
 
-        return await db.Teachers.AsNoTracking()
+        var candidates = await InvigilatorCandidateQuery
-            .Where(x => x.Status == TeacherStatus.Active)
+            .Create(db, busyTeacherIds)
-            .WhereNotIn(busyTeacherIds, x => x.Id)
-            .OrderBy(x => Guid.NewGuid())
-            .Take(needed)
             .ToListAsync(cancellationToken);
+
+        return candidates
+            .OrderBy(_ => Random.Shared.Next())
+            .Take(needed)
+            .ToList();
     }
 }

tests/Jiaowu.Api.Tests/ExamArrangementServiceTests.cs

@@ -9,7 +9,7 @@ namespace Jiaowu.Api.Tests;
 public sealed class ExamArrangementServiceTests
 {
     [Fact]
-    public async Task Normal_arrangement_only_updates_selected_sessions_and_requested_resource()
+    public async Task Normal_arrangement_only_updates_selected_session()
     {
         await using var connection = new SqliteConnection("Data Source=:memory:");
         await connection.OpenAsync();
@@ -37,21 +37,27 @@ public sealed class ExamArrangementServiceTests
             plan.Id,
             [selected.Id],
             assignClassrooms: true,
-            assignInvigilators: false,
+            assignInvigilators: true,
             CancellationToken.None);
 
-        var persistedSelected = await db.ExamSessions.FindAsync(selected.Id);
+        var persistedSelected = await db.ExamSessions
-        var persistedUntouched = await db.ExamSessions.FindAsync(untouched.Id);
+            .Include(x => x.Invigilators)
+            .SingleAsync(x => x.Id == selected.Id);
+        var persistedUntouched = await db.ExamSessions
+            .Include(x => x.Invigilators)
+            .SingleAsync(x => x.Id == untouched.Id);
         Assert.True(result.Success);
-        Assert.NotNull(persistedSelected!.ClassroomId);
+        Assert.NotNull(persistedSelected.ClassroomId);
-        Assert.Null(persistedUntouched!.ClassroomId);
+        Assert.Null(persistedUntouched.ClassroomId);
-        Assert.Empty(persistedSelected.Invigilators);
+        Assert.Single(persistedSelected.Invigilators);
+        Assert.Empty(persistedUntouched.Invigilators);
         Assert.Contains("1个场次处理完成", result.Message);
+        Assert.Contains("1名监考教师", result.Message);
         Assert.Contains("程序设计", result.Message);
     }
 
     [Fact]
-    public async Task Makeup_arrangement_only_updates_selected_sessions_and_requested_resource()
+    public async Task Makeup_arrangement_only_updates_selected_session()
     {
         await using var connection = new SqliteConnection("Data Source=:memory:");
         await connection.OpenAsync();
@@ -79,16 +85,22 @@ public sealed class ExamArrangementServiceTests
             plan.Id,
             [selected.Id],
             assignClassrooms: true,
-            assignInvigilators: false,
+            assignInvigilators: true,
             CancellationToken.None);
 
-        var persistedSelected = await db.MakeupExamSessions.FindAsync(selected.Id);
+        var persistedSelected = await db.MakeupExamSessions
-        var persistedUntouched = await db.MakeupExamSessions.FindAsync(untouched.Id);
+            .Include(x => x.Invigilators)
+            .SingleAsync(x => x.Id == selected.Id);
+        var persistedUntouched = await db.MakeupExamSessions
+            .Include(x => x.Invigilators)
+            .SingleAsync(x => x.Id == untouched.Id);
         Assert.True(result.Success);
-        Assert.NotNull(persistedSelected!.ClassroomId);
+        Assert.NotNull(persistedSelected.ClassroomId);
-        Assert.Null(persistedUntouched!.ClassroomId);
+        Assert.Null(persistedUntouched.ClassroomId);
-        Assert.Empty(persistedSelected.Invigilators);
+        Assert.Single(persistedSelected.Invigilators);
+        Assert.Empty(persistedUntouched.Invigilators);
         Assert.Contains("1个场次处理完成", result.Message);
+        Assert.Contains("1名监考教师", result.Message);
         Assert.Contains("程序设计", result.Message);
     }
 
@@ -175,6 +187,13 @@ public sealed class ExamArrangementServiceTests
             CourseId = secondCourse.Id,
             Status = TeachingTaskStatus.Published
         };
+        var invigilator = new Teacher
+        {
+            TeacherNumber = $"INVIGILATOR-{suffix}",
+            Name = "监考教师",
+            CollegeId = college.Id,
+            Status = TeacherStatus.Active
+        };
 
         db.AddRange(
             term,
@@ -186,6 +205,7 @@ public sealed class ExamArrangementServiceTests
             secondCourse,
             firstTask,
             secondTask,
+            invigilator,
             new ScheduleTimeSlot
             {
                 AcademicTermId = term.Id,

tests/Jiaowu.Api.Tests/MySqlMigrationTests.cs

@@ -1,4 +1,5 @@
 using Jiaowu.Api.Infrastructure.Persistence;
+using Jiaowu.Api.Infrastructure.Exams;
 using Jiaowu.Api.Infrastructure.Teaching;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Infrastructure;
@@ -99,6 +100,21 @@ public sealed class MySqlMigrationTests
         Assert.Contains(ids[1].ToString(), sql, StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public void MySql_invigilator_candidate_query_is_translatable_without_uuid_ordering()
+    {
+        using var db = new AppDbContext(CreateMySqlOptions());
+        var excludedTeacherId =
+            Guid.Parse("11111111-1111-1111-1111-111111111111");
+
+        var sql = InvigilatorCandidateQuery
+            .Create(db, [excludedTeacherId])
+            .ToQueryString();
+
+        Assert.Contains("Teachers", sql, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("UUID(", sql, StringComparison.OrdinalIgnoreCase);
+    }
+
     [Fact]
     public void MySql_teaching_task_roster_query_is_translatable()
     {