refactor(server): rename tx to db (#9867)

packages/backend/server/src/models/base.ts

@@ -1,7 +1,6 @@
 import { Inject, Logger } from '@nestjs/common';
 import { TransactionHost } from '@nestjs-cls/transactional';
 import type { TransactionalAdapterPrisma } from '@nestjs-cls/transactional-adapter-prisma';
-import { PrismaClient } from '@prisma/client';
 
 import { Config } from '../base';
 import type { Models } from '.';
@@ -16,13 +15,12 @@ export class BaseModel {
   @Inject(Config)
   protected readonly config!: Config;
 
-  @Inject(PrismaClient)
-  protected readonly db!: PrismaClient;
-
   @Inject(TransactionHost)
   private readonly txHost!: TransactionHost<TransactionalAdapterPrisma>;
 
-  protected get tx() {
+  protected get db() {
+    // When a transaction is not active, the Transaction instance refers to the default non-transactional instance.
+    // See https://papooch.github.io/nestjs-cls/plugins/available-plugins/transactional#using-the-injecttransaction-decorator
     return this.txHost.tx;
   }
 }