define the properties as specific as possible

src/performance/models/performance.model.ts

@@ -1,24 +1,42 @@
 import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
 import { Document } from 'mongoose';
-import { PerformanceEntry } from './performanceentry.model';
+import {
+  PerformanceEntry,
+  PerformanceEntrySchema,
+} from './performanceentry.model';
 
 export type PerformanceDocument = Performance & Document;
 
 @Schema()
 export class Performance {
-  @Prop({ required: true })
+  @Prop({
+    type: String,
+    required: true,
+  })
   icaoCode: string;
 
-  @Prop({ required: true, type: PerformanceEntry })
+  @Prop({
+    required: true,
+    type: PerformanceEntrySchema,
+  })
   aboveFL240: PerformanceEntry;
 
-  @Prop({ required: true, type: PerformanceEntry })
+  @Prop({
+    required: true,
+    type: PerformanceEntrySchema,
+  })
   aboveFL100: PerformanceEntry;
 
-  @Prop({ required: true, type: PerformanceEntry })
+  @Prop({
+    required: true,
+    type: PerformanceEntrySchema,
+  })
   belowFL100: PerformanceEntry;
 
-  @Prop({ required: true })
+  @Prop({
+    required: true,
+    type: Number,
+  })
   minimalApproachSpeed: number;
 }