前情概要

在使用nodejs开发过程中，刚好碰到需要做一个小工具，需要用到数据库存储功能。而我又比较懒，一个小功能不想搞一个nodejs项目，又搞一个后端项目。不如直接在nodejs里面把对数据库的操作也做掉。
结果百度一圈下来发现nodejs这边还都是比较原始的、类似后端的通过coneection连数据库，接着open，在写sql语句干嘛干嘛的。经过后端这么多年的脚手架工具熏陶，实在懒得写这些没营养的简单增删改查sql语句了。
typeorm github地址
typeorm github地址
遂通过baidu、google找到了typeorm这个orm框架。果然不错，作者自己也说大量参考了如entityframework、hibernate、dapper等等众多orm框架。吸收了各家之所长。
更多介绍和各种示例可以参考它的demo项目，基本每个数据库都有一个demo，然后对特性也基本都介绍到的。
比如mongodb如何映射复杂对象，关系型数据怎么弄级联删除之类的功能

使用总结

mysql、sqlite、mongodb3个数据库下都使用过，使用感觉虽然没有后端的orm那么强大，但是在nodejs领域内，orm我觉得它已经可以说是no.1啦。当然不排除我孤陋寡闻漏了更NB的其他框架。
绝大多数的后端orm该有的功能它都有，没有可能是没找到正确的使用方式。为此我还发过几条issue给开发者。基本上自己最后google找到解决方或者组件作者给与了回复。
基本功能介绍可以直接去GitHub看，基本上orm应该要有的功能它都有了。

typeorm 项目介绍

此项目github上的第一句介绍：
ORM for TypeScript and JavaScript (ES7, ES6, ES5). Supports MySQL, PostgreSQL, MariaDB, SQLite, MS SQL Server, Oracle, WebSQL databases. Works in NodeJS, Browser, Ionic, Cordova and Electron platforms.

remark：
TypeORM is highly influenced by other ORMs, such as Hibernate, Doctrine and Entity Framework.

Some TypeORM features:

• supports both DataMapper and ActiveRecord (your choice)
• entities and columns
• database-specific column types
• entity manager
• repositories and custom repositories
• clean object relational model
• associations (relations)
• eager and lazy relations
• uni-directional, bi-directional and self-referenced relations
• supports multiple inheritance patterns
• cascades
• indices
• transactions
• migrations and automatic migrations generation
• connection pooling
• replication
• using multiple database connections
• working with multiple databases types
• cross-database and cross-schema queries
• elegant-syntax, flexible and powerful QueryBuilder
• left and inner joins
• proper pagination for queries using joins
• query caching
• streaming raw results
• logging
• listeners and subscribers (hooks)
• supports closure table pattern
• schema declaration in models or separate configuration files
• connection configuration in json / xml / yml / env formats
• supports MySQL / MariaDB / Postgres / SQLite / Microsoft SQL Server / Oracle / sql.js
• supports MongoDB NoSQL database
• works in NodeJS / Browser / Ionic / Cordova / React Native / NativeScript / Expo / Electron platforms
• TypeScript and JavaScript support
• produced code is performant, flexible, clean and maintainable
• follows all possible best practices
• CLI
  And more...

个人的一些用法-mongodb

都是一些非常简单的封装，直接贴代码啦。

typeorm mongodb 初始化配置

比如数据库链接字符串，实体类，还有一些其他配置等等

InitMongoDb({
    url: _appConfig.mongodb.url,
    entities: ['bin/Entity/*.js'],
    synchronize: true,
    logging: false
});
export function InitMongoDb(dbName: string, mongoOptions: MongoConnectionOptions): void;
export function InitMongoDb(mongoOptions: MongoConnectionOptions): void;
export function InitMongoDb(): void {
    var options: MongoConnectionOptions = arguments[0];
    var dbName: any;
    if (typeof arguments[0] === 'string') {
        dbName = arguments[0];
        options = arguments[1];
    }

    var dbName = dbName || 'default';

    ManangerMongoConnection.ConnectOptions[dbName] = {
        hasGetConnection: false,
        options: options
    };
}

typeorm mongodb repository管理器

export async function getMongoRepositoryAsync(entityClass: ObjectType): Promise>;
export async function getMongoRepositoryAsync(entityClass: ObjectType, dbName: string): Promise>
export async function getMongoRepositoryAsync(): Promise> {
    var entityClass = arguments[0] as ObjectType;
    var dbName = (arguments.length > 1 ? arguments[1] : undefined) || 'default';

    var conn = await new ManangerMongoConnection().getConnection(dbName);
    var repo = conn.getMongoRepository(entityClass);
    var gdRepo = new GDMongoRepository(repo)
    return gdRepo;
}

class ManangerMongoConnection {
    static ConnectOptions: any = {};

    async getConnection(dbName: string): Promise {
        var conf = ManangerMongoConnection.ConnectOptions[dbName];
        if (!conf)
            throw Error(`找不到(${dbName})的数据库配置`);
        if (conf.hasCreated)
            return conf.connection;

        var options = conf.options as MongoConnectionOptions;
        var conn = await createConnection({
            type: 'mongodb',
            url: options.url,
            synchronize: options.synchronize,
            logging: options.logging,
            entities: options.entities
        });
        conf.connection = conn;
        conf.hasCreated = true;
        return conn;
    }
}

typeorm mongodb repository 简单封装

import { ObjectType, FindManyOptions, MongoRepository, ObjectLiteral, Connection, createConnection, Entity, ObjectIdColumn, Column, ObjectID, getManager } from "typeorm";
import { ObjectId } from 'mongodb'

export class GDMongoRepository {
    private _repo: MongoRepository;
    constructor(repo: MongoRepository) {
        this._repo = repo;
    }
    SaveAsync(docment: TEntity): Promise {
        if (!docment.createdTime) docment.createdTime = new Date();
        return this._repo.save(docment);
    }
    FindByIdAsync(id: number | string) {
        return this._repo.findOneById(new ObjectId(id));
    }

    FindByIdsAsync(ids: number[] | string[]) {
        var _id: ObjectId[] = [];
        for (let index = 0; index < ids.length; index++) {
            const element = ids[index];
            _id.push(new ObjectId(element));
        }
        return this._repo.findByIds(_id);
    }
    FindAsync(optionsOrConditions?: FindManyOptions | Partial | ObjectLiteral): Promise {
        return this._repo.find(optionsOrConditions)
    }

    CountAsync(optionsOrConditions?: FindManyOptions | Partial | ObjectLiteral): Promise {
        var query: any = Object.assign({}, optionsOrConditions);
        if (query.take) delete query.take;
        if (query.skip) delete query.skip;
        if (query.order) delete query.order;
        query = query.where || query;
        return this._repo.count(query)
    }
    FindAndCount(optionsOrConditions?: FindManyOptions | Partial): Promise<[TEntity[], number]> {
        return this._repo.findAndCount(optionsOrConditions)
    }

    AggregateAsync(pipeline: ObjectLiteral[]): Promise {
        return this._repo.aggregate(pipeline).toArray()
    }
    async RemoveByIdAsync(id: number | string): Promise {
        var r = await this._repo.deleteOne({ _id: new ObjectId(id) });
        if (r.deletedCount)
            return r.deletedCount
        return 0;
    }
    async RemoveAsync(conditions: ObjectLiteral): Promise {
        var r = await this._repo.deleteMany(conditions);
        if (r.deletedCount)
            return r.deletedCount
        return 0;
    }

    async UpdateByIdAsync(id: number | string, update: ObjectLiteral | Partial): Promise {
        if (update.$set || update.$unset || update.$rename) { }
        else {
            update = { $set: update }
        }
        update.$set.lastModifyTime = new Date();
        var r = await this._repo.updateOne({ _id: new ObjectId(id) }, update);
        return r.modifiedCount;
    }

    async UpdateAsync(query: FindManyOptions | Partial | ObjectLiteral, update: ObjectLiteral | Partial): Promise {
        if (update.$set || update.$unset || update.$rename) { }
        else {
            update = { $set: update }
        }
        update.$set.lastModifyTime = new Date();
        var r = await this._repo.updateMany(query, update);
        return r.modifiedCount;
    }
}

一些简单的使用例子

    public async list() {
        var repo = await getMongoRepositoryAsync(Host);
        var b = await repo.FindAsync();
        return b
    }

    public async info() {
        var repo = await getMongoRepositoryAsync(Host);
        var b = await repo.FindAsync({ Ip: this.request.query.ip, HostEnv: this.request.query.env });
        return b
    }

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