如果模型仅在根模块中，如何注入模型

Question

我想在NestJS服务中注入一个mongo-db模型。该模型仅存在于根模块中。

import { Injectable } from '@nestjs/common';
import { InjectModel } from '@nestjs/mongoose';
import { Model } from 'mongoose';
import { IFolderModel } from './interfaces/folder.interface';
@Injectable()
export class FolderService {
constructor(@InjectModel('IFolder') private folderModel: Model<IFolderModel>) {
}
async create(folderInstance: IFolderModel): Promise<IFolderModel> {
const folderModelToBeSaved = new this.folderModel(folderInstance);
return await folderModelToBeSaved.save();
}
async findAll(): Promise<IFolderModel[]> {
return await this.folderModel.find().exec();
}
} 

我在使用npm run start启动应用程序时出现以下错误

Error: Nest can't resolve dependencies of the FolderService (?). Please make sure that the argument at index [0] is available in the AppModule context.

AppModule 的内容

let mongodb = env.mongodb;
let url = `mongodb://${mongodb.user}:${mongodb.pwd}@${mongodb.host}:${mongodb.port}/${mongodb.dbName}`;
@Module({
imports: [MongooseModule.forRoot(url)],
controllers: [AppController, FolderController],
providers: [AppService, FolderService],
})
export class AppModule { }

Answer 1

您还必须使用MongooseModule.forFeature导入架构。通常，您会在根模块中设置数据库连接，然后在专用功能模块中导入模式。这就是为什么进口是分开的。

MongooseModule.forFeature([{ name: 'Folder', schema: FolderSchema }])

有关更多信息，请参阅mongo文档。