index.js

const mysql = require('mysql');

let connection;
let insertQueue = {};
let createQueue = {};
let databaseName = '';

function Model(name, option) {
    this.name = name;
    this.option = option;
};


/**
* @description: 查询数据
* @param {} options：可选参数
* @param {Function} callback :（req,results）=>{}
*/
Model.prototype.find = function (options, callback) {
    var str = '';
    if (!callback) {
        str = `select * from ${this.name}`;
        callback = options;
    } else if (options.constructor == Array) {
        str = `select ${options.join()} from ${this.name}`;
    } else {
        str = `select * from ${this.name} where ${options}`;
    };
    //console.log(str);
    connection.query(str, (error, results, fields) => {
        callback(error, results, fields);
    });
    return this;
};

/**
* @description: 分页查询
* @param {Object} options :   { where:查询条件, number: 当前页数 , count : 每页数量 }
* @return: 
*/
Model.prototype.limit = function (options, callback) {
    var str = '';
    if (!options.where) {
        str = `select * from ${this.name} limit ${(options.number - 1)*options.count},${options.count}`;
    }else {
        str = str = `select * from ${this.name} where ${options.where} limit ${(options.number - 1)*options.count},${options.count}`;
    };
    console.log(str);
    connection.query(str, (error, results, fields) => {
        callback(error, results, fields);
    });
    return this;
};

/**
* @description: 插入数据
* @param {Object} 
* @param {Function} callback :（req,results）=>{}
*/
Model.prototype.insert = function (obj, callback) {
    //先执行一次，激活数据库
    let keys = [];
    let values = '';
    for (var key in obj) {
        keys.push(key);
        values += `"${obj[key]}",`;
    };
    values = values.replace(/,$/, '');
    let str = `INSERT INTO ${this.name} (${keys.join()}) VALUES (${values})`;
    //console.log(str);

    var model1 = this;
    connection.query(str, (error, results, fields) => {
        if (error && !insertQueue.obj) {
            insertQueue.obj = obj;
            insertQueue.callback = callback;
            insertQueue.model = model1;
        }else{
            callback(error,results,fields);
        }
    });
    return this;
};

/**
* @description: 更新数据
* @param {Object} option：可选参数 更新条件
* @param {Object} obj： 修改后的数据 
* @param {Function} callback :（req,results）=>{}
*/
Model.prototype.update = function (option, obj, callback) {
    let str = '';
    if (arguments.length == 2) {
        callback = obj;
        obj = option;
        str = `UPDATE ${this.name} SET `;
        for (var key in obj) {
            str += `${key}='${obj[key]}', `;
        };
        str = str.replace(/(, )$/, '');
    } else {
        str = `UPDATE ${this.name} SET `;
        for (var key in obj) {
            str += `${key}='${obj[key]}', `;
        };
        str = str.replace(/(, )$/, '');
        str += ` where ${option}`;
    };

    console.log(str);
    connection.query(str, (error, results, fields) => {
        callback(error, results, fields);
    });
    return this;

};

/**
* @description: 删除数据
* @param {Object} option：可选参数 删除条件
* @param {Function} callback :（req,results）=>{}
*/
Model.prototype.delete = function (option, callback) {
    var str = '';
    if (!callback) {
        str = `delete from ${this.name}`;
        callback = option;
    } else {
        str = `delete from ${this.name} where ${option}`;
    };
    console.log(str);
    connection.query(str, (error, results, fields) => {
        callback(error, results, fields);
    });
    return this;
};

/**
* @description: 执行sql语句
* @param {String} str : sql语句
* @param {Function} callback :（req,results）=>{}
*/
Model.prototype.sql = function (str, callback) {
    connection.query(str, (error, results, fields) => {
        callback(error, results, fields);
    });
    return this;
};

/**
* @description: 删除model表格 （慎用！）
* @param {type} 
* @return: 
*/
Model.prototype.drop = function (callback) {
    connection.query(`DROP TABLE ${this.name}`, (error, results, fields) => {
        callback(error, results, fields);
    });
    return this;
};

let hm = {
    /**
    * @description:连接数据库
    * @param {String} host: 主机名 默认localhost
    * @param {Number} port: 端口号 默认3306
    * @param {String} user: 用户名 默认root
    * @param {String} password: 密码 默认root
    * @param {String} database: 数据库名称 默认hm
    * @return: 
    */
    connect: function ({ host = 'localhost', port = 3306, user = 'root', password = 'root', database = 'hm' }) {
        databaseName = database;//全局存储当前数据库名称

        connection = mysql.createConnection({
            host,//数据库地址
            port,//端口号
            user,//用户名，没有可不填
            password,//密码，没有可不填
            database//数据库名称
        });
        connection.connect((err) => {
            if (err) {
                //console.log(connection);
                connection = mysql.createConnection({
                    host,//数据库地址
                    port,//端口号
                    user,//用户名，没有可不填
                    password,//密码，没有可不填
                });
                connection.connect((err) => {
                    //if (err) throw error;
                    connection.query(`CREATE DATABASE ${database}`, (error, results, fields) => {
                        //if (error) throw error;
                        connection.query(`use ${database}`, (error, results, fields) => {
                            if (!error) {
                                if (createQueue.name) {
                                    hm.model(createQueue.name,createQueue.options);
                                }
                            }
                        });

                    });
                });
            }
        });
    },
    /**
    * @description:创建model (表格模型对象)
    * @param {String} name:表格名称
    * @param {Object} options:表格数据结构
    * @return: Model对象：负责数据库增删改查
    */
    model: function (name, options) {
        let str = 'id int primary key auto_increment, ';
        for (var key in options) {
            if (options[key] == Number) {
                str += `${key} numeric,`;
            } else if (options[key] == Date) {
                str += `${key} timestamp,`;
            } else {
                str += `${key} varchar(255),`;
            }
        };
        str = str.replace(/,$/, '');
        console.log(`CREATE TABLE ${name} (${str})`);
        //console.log(str);
        connection.query(`CREATE TABLE ${name} (${str})`, (error, results, fields) => {
            if (error) {
                createQueue.name = name;
                createQueue.options = options;
            }else{
                insertQueue.model.insert(insertQueue.obj,insertQueue.callback);
            }
        });
        return new Model(name, options);
    }
};

module.exports = hm;