在EggJS中使用Sequelize作聯表查詢

時間  2019-11-08
標籤 eggjs 使用 sequelize 查詢 简体版
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1.EggJS引用Sequelize

  1. 安裝sequelize依賴和mysql驅動mysql

    cnpm i egg-sequelize mysql2 -S
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  2. 啓用sequelize插件git

    在config/plugin.js裏面添加github

    sequelize: {
    enable: true,
    package: 'egg-sequelize',
},
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  3. 配置數據庫sql

    在config/config.default.js裏面添加數據庫

    config.sequelize = {
    dialect: 'mysql',  // 表示使用mysql
    host: '127.0.0.1', // 鏈接的數據庫主機地址
    port: 3306, // mysql服務端口
    database: 'demo', // 數據庫名
    username: 'root',  // 數據庫用戶名
    password: 'root', // 數據庫密碼
    define: {  // model的全局配置
      	timestamps: true,   // 添加create,update,delete時間戳
      	paranoid: true,   // 添加軟刪除
      	freezeTableName: true,  // 防止修改表名爲複數
      	underscored: false  // 防止駝峯式字段被默認轉爲下劃線
    },
    timezone: '+8:00',  // 因爲orm用的UTC時間，這裏必須加上東八區，不然取出來的時間相差8小時
    dialectOptions: {  // 讓讀取date類型數據時返回字符串而不是UTC時間
        dateStrings: true,
        typeCast(field, next) {
            if (field.type === "DATETIME") {
                return field.string();
            }
            return next();
        }
    }
};
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2.定義Model

  1. 剛開始使用egg-init構建的Egg項目是沒有app/model目錄的，初始的項目結構以下:npm

    itzishu
├── README.md
├── app
│   ├── controller
│   │   └── home.js
│   └── router.js
├── appveyor.yml
├── config
│   ├── config.default.js
│   └── plugin.js
├── package.json
└── test
    └── app
        └── controller
            └── home.test.js
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    先在app目錄下新建一個目錄爲model，裏面用來存放全部的數據庫裏面定義的表的實例對象內容。json

  2. 數據庫表的內容以下：數組

    /*
 Navicat Premium Data Transfer

 Source Server         : 系統數據庫3306
 Source Server Type    : MySQL
 Source Server Version : 50725
 Source Host           : localhost:3306
 Source Schema         : demo

 Target Server Type    : MySQL
 Target Server Version : 50725
 File Encoding         : 65001

 Date: 12/05/2019 15:11:37
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for classes
-- ----------------------------
DROP TABLE IF EXISTS `classes`;
CREATE TABLE `classes` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `createdAt` datetime DEFAULT NULL,
  `updatedAt` datetime DEFAULT NULL,
  `deletedAt` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of classes
-- ----------------------------
BEGIN;
INSERT INTO `classes` VALUES (1, '軟件工程1601', '2019-05-12 13:11:43', '2019-05-12 13:11:47', NULL);
INSERT INTO `classes` VALUES (2, '網絡工程1601', '2019-05-12 13:12:10', '2019-05-12 13:12:13', NULL);
COMMIT;

-- ----------------------------
-- Table structure for info
-- ----------------------------
DROP TABLE IF EXISTS `info`;
CREATE TABLE `info` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `age` int(11) NOT NULL,
  `sex` tinyint(255) NOT NULL DEFAULT '1' COMMENT '1爲男，0爲女',
  `studentId` int(11) NOT NULL,
  `createdAt` datetime DEFAULT NULL,
  `updatedAt` datetime DEFAULT NULL,
  `deletedAt` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of info
-- ----------------------------
BEGIN;
INSERT INTO `info` VALUES (1, '許仙', 23, 1, 1, '2019-05-12 13:25:58', '2019-05-12 13:26:01', NULL);
INSERT INTO `info` VALUES (2, '白素貞', 20, 0, 2, '2019-05-12 13:26:41', '2019-05-12 13:26:46', NULL);
INSERT INTO `info` VALUES (3, '法海', 22, 1, 3, '2019-05-12 13:27:20', '2019-05-12 13:27:22', NULL);
INSERT INTO `info` VALUES (4, '小青', 18, 0, 4, '2019-05-12 13:27:48', '2019-05-12 13:27:51', NULL);
INSERT INTO `info` VALUES (5, '金如意', 20, 0, 5, '2019-05-12 13:28:34', '2019-05-12 13:28:37', NULL);
INSERT INTO `info` VALUES (6, '景鬆', 23, 1, 6, '2019-05-12 13:30:07', '2019-05-12 13:30:10', NULL);
COMMIT;

-- ----------------------------
-- Table structure for lession
-- ----------------------------
DROP TABLE IF EXISTS `lession`;
CREATE TABLE `lession` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `createdAt` datetime DEFAULT NULL,
  `updatedAt` datetime DEFAULT NULL,
  `deletedAt` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of lession
-- ----------------------------
BEGIN;
INSERT INTO `lession` VALUES (1, '計算機網絡', '2019-05-12 13:12:32', '2019-05-12 13:12:35', NULL);
INSERT INTO `lession` VALUES (2, 'Java程序設計', '2019-05-12 13:12:50', '2019-05-12 13:12:52', NULL);
INSERT INTO `lession` VALUES (3, '軟件項目管理', '2019-05-12 13:13:07', '2019-05-12 13:13:10', NULL);
INSERT INTO `lession` VALUES (4, '網絡安全', '2019-05-12 13:13:22', '2019-05-12 13:13:25', NULL);
COMMIT;

-- ----------------------------
-- Table structure for lession_student
-- ----------------------------
DROP TABLE IF EXISTS `lession_student`;
CREATE TABLE `lession_student` (
  `lessionId` int(11) NOT NULL,
  `studentId` int(11) NOT NULL,
  `createdAt` datetime DEFAULT NULL,
  `updatedAt` datetime DEFAULT NULL,
  `deletedAt` datetime DEFAULT NULL,
  PRIMARY KEY (`lessionId`,`studentId`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of lession_student
-- ----------------------------
BEGIN;
INSERT INTO `lession_student` VALUES (1, 1, '2019-05-12 13:20:35', '2019-05-12 13:20:40', NULL);
INSERT INTO `lession_student` VALUES (1, 2, '2019-05-12 13:20:51', '2019-05-12 13:20:53', NULL);
INSERT INTO `lession_student` VALUES (1, 3, '2019-05-12 13:21:02', '2019-05-12 13:21:05', NULL);
INSERT INTO `lession_student` VALUES (1, 4, '2019-05-12 13:21:15', '2019-05-12 13:21:19', NULL);
INSERT INTO `lession_student` VALUES (1, 5, '2019-05-12 13:21:29', '2019-05-12 13:21:32', NULL);
INSERT INTO `lession_student` VALUES (1, 6, '2019-05-12 13:21:43', '2019-05-12 13:21:45', NULL);
INSERT INTO `lession_student` VALUES (2, 1, '2019-05-12 13:23:10', '2019-05-12 13:23:13', NULL);
INSERT INTO `lession_student` VALUES (2, 3, '2019-05-12 13:23:28', '2019-05-12 13:23:31', NULL);
INSERT INTO `lession_student` VALUES (2, 4, '2019-05-12 13:23:40', '2019-05-12 13:23:43', NULL);
INSERT INTO `lession_student` VALUES (2, 5, '2019-05-12 13:23:54', '2019-05-12 13:23:57', NULL);
INSERT INTO `lession_student` VALUES (3, 1, '2019-05-12 13:24:21', '2019-05-12 13:24:24', NULL);
INSERT INTO `lession_student` VALUES (3, 4, '2019-05-12 13:24:39', '2019-05-12 13:24:42', NULL);
INSERT INTO `lession_student` VALUES (4, 2, '2019-05-12 13:24:59', '2019-05-12 13:25:03', NULL);
INSERT INTO `lession_student` VALUES (4, 6, '2019-05-12 13:25:12', '2019-05-12 13:25:15', NULL);
COMMIT;

-- ----------------------------
-- Table structure for student
-- ----------------------------
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `number` varchar(12) NOT NULL COMMENT '學號',
  `password` varchar(32) NOT NULL,
  `classId` int(11) NOT NULL,
  `createdAt` datetime DEFAULT NULL,
  `updatedAt` datetime DEFAULT NULL,
  `deletedAt` datetime DEFAULT NULL,
  PRIMARY KEY (`id`,`number`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of student
-- ----------------------------
BEGIN;
INSERT INTO `student` VALUES (1, '160101', '202cb962ac59075b964b07152d234b70', 1, '2019-05-12 13:16:09', '2019-05-12 13:16:12', NULL);
INSERT INTO `student` VALUES (2, '160201', '202cb962ac59075b964b07152d234b70', 2, '2019-05-12 13:16:32', '2019-05-12 13:16:35', NULL);
INSERT INTO `student` VALUES (3, '160102', '202cb962ac59075b964b07152d234b70', 1, '2019-05-12 13:17:17', '2019-05-12 13:17:21', NULL);
INSERT INTO `student` VALUES (4, '160103', '202cb962ac59075b964b07152d234b70', 1, '2019-05-12 13:17:51', '2019-05-12 13:17:54', NULL);
INSERT INTO `student` VALUES (5, '160104', '202cb962ac59075b964b07152d234b70', 1, '2019-05-12 13:18:13', '2019-05-12 13:18:16', NULL);
INSERT INTO `student` VALUES (6, '160202', '202cb962ac59075b964b07152d234b70', 2, '2019-05-12 13:18:36', '2019-05-12 13:18:39', NULL);
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

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    其中，各個表之間存在聯繫爲：安全

    • student與info存在一對一關係
    • classes與student存在一對多關係
    • student與lession存在多對多關係，中間表爲lession_student

  3. 根據數據表的結構，咱們肯定關係並寫好model目錄下相關文件

    • student.js
    module.exports = app => {
    const { STRING, INTEGER } = app.Sequelize;

    const Student = app.model.define('student', {
        id: {
            type: INTEGER,
            autoIncrement: true,
            primaryKey: true
        },
        number: {
            type: STRING,
            allowNull: false,
        },
        password: {
            type: STRING(32),
            allowNull: false
        },
        classId: {
            type: INTEGER,
            allowNull: false
        }
    });

    Student.associate = function (){
        // 與Info存在一對多關係，因此是hasOne()
        app.model.Student.hasOne(app.model.Info, {foreignKey: 'studentId'});
        // 與Classes存在多對一關係，因此使用belongsTo()
        app.model.Student.belongsTo(app.model.Classes, {foreignKey: 'classId', targetKey: 'id'});
        // 與Lessison存在多對多關係，使用belongsToMany()
        app.model.Student.belongsToMany(app.model.Lession, {
            through: app.model.LessionStudent,
            foreignKey: 'studentId',
            otherKey: 'lessionId'
        });
    }

    return Student;
}
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    • info.js
    module.exports = app => {
    const { STRING, INTEGER, BOOLEAN } = app.Sequelize;

    const Info = app.model.define('info', {
        id: {
            type: INTEGER,
            autoIncrement: true,
            primaryKey: true
        },
        name: {
            type: STRING(50),
            allowNull: false,
        },
        age: {
            type: INTEGER,
            allowNull: false
        },
        sex: {
            type: BOOLEAN,
            allowNull: false,
            get() {
                if ( this.getDataValue('sex') ){
                    return '男';
                }else {
                    return '女';
                }
            }
        },
        studentId: {
            type: INTEGER,
            allowNull: false
        }
    });

    Info.associate = function (){
        app.model.Info.belongsTo(app.model.Student, {foreignKey: 'studentId', targetKey: 'id'});
    }

    return Info;
}
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    這裏注意下，在sex字段中，有一個get(){}方法，由於在數據表裏面，sex字段存了1或0 ，1爲男0爲女，爲了直接返回"男"或"女"，這裏使用get方法在找到數據後先作了處理，那返回給調用的函數的數據就是咱們設置的值

    • classes.js
    module.exports = app => {
    const { STRING, INTEGER, BOOLEAN } = app.Sequelize;

    const Classes = app.model.define('classes', {
        id: {
            type: INTEGER,
            autoIncrement: true,
            primaryKey: true
        },
        name: {
            type: STRING(50),
            allowNull: false,
        },
        age: {
            type: INTEGER,
            allowNull: false
        },
        sex: {
            type: BOOLEAN,
            allowNull: false,
            get() {
                if ( this.getDataValue('sex') ){
                    return '男';
                }else {
                    return '女';
                }
            }
        },
        studentId: {
            type: INTEGER,
            allowNull: false
        }
    });

    Classes.associate = function (){
        // classes與student是一對多關係，因此這裏使用hasMany()
        app.model.Classes.hasMany(app.model.Student, {foreignKey: 'classId', targetKey: 'id'});
    }

    return Classes;
}
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    • lession.js
    module.exports = app => {
    const { INTEGER, STRING } = app.Sequelize;

    const Lession = app.model.define('lession', {
        id: {
            type: INTEGER,
            primaryKey: true,
            autoIncrement: true
        },
        name: {
            type: STRING,
            allowNull: false
        }
    });

    Lession.associate = function(){
        // 與student表是多對多關係
        app.model.Lession.belongsToMany(app.model.Student, {
            through: app.model.LessionStudent,
            foreignKey: 'lessionId',
            otherKey: 'studentId'
        });
    }

    return Lession;
}
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    • lession-student.js
    module.exports = app => {
    const { INTEGER } = app.Sequelize;

    const LessionStudent = app.model.define('lession_student', {
        lessionId: {
            type: INTEGER,
            primaryKey: true
        },
        studentId: {
            type: INTEGER,
            primaryKey: true
        }
    });

    LessionStudent.associate = function(){

    }

    return LessionStudent;
}
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  4. 總結一下Model定義的內容

    • 針對MYSQL經常使用的字段類型

    字段類型從 app.Sequelize 獲取，對應名字以下

    Sequelize.STRING                      // VARCHAR(255)
Sequelize.STRING(1234)                // VARCHAR(1234)
Sequelize.STRING.BINARY               // VARCHAR BINARY
Sequelize.TEXT                        // TEXT
Sequelize.TEXT('tiny')                // TINYTEXT

Sequelize.INTEGER                     // INTEGER
Sequelize.BIGINT                      // BIGINT
Sequelize.BIGINT(11)                  // BIGINT(11)

Sequelize.FLOAT                       // FLOAT
Sequelize.FLOAT(11)                   // FLOAT(11)
Sequelize.FLOAT(11, 12)               // FLOAT(11,12)

Sequelize.DOUBLE                      // DOUBLE
Sequelize.DOUBLE(11)                  // DOUBLE(11)
Sequelize.DOUBLE(11, 12)              // DOUBLE(11,12)

Sequelize.DECIMAL                     // DECIMAL
Sequelize.DECIMAL(10, 2)              // DECIMAL(10,2)

Sequelize.DATE                        // DATETIME 針對 mysql / sqlite, TIMESTAMP WITH TIME ZONE 針對 postgres
Sequelize.DATE(6)                     // DATETIME(6) 針對 mysql 5.6.4+. 小數秒支持多達6位精度
Sequelize.DATEONLY                    // DATE 不帶時間.
Sequelize.BOOLEAN                     // TINYINT(1)
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    其餘的數據庫所容許的類型參考：數據類型

    • 字段屬性值
    屬性名 類型 默認值 說明 說明
    type Any 無 是 數據類型
    primaryKey Boolean false 否 主鍵
    autoIncrement Boolean false 否 自增
    allowNull Boolean false 否 是否容許爲空
    defaultValue Any 無 否 默認值
    field String 字段名 否 自定義字段名
    unique Any 無 否 約束
    • 表與表的關聯性

    在sequelize中，表與表之間用代碼來講存在三種關聯關係：一對一，一對多，多對多

    1. 一對一

      在該項目中，student表和info表是存在一對一關係的，一個學生有一條專屬信息。

      在student.js中，使用了hasOne()方法，第一個參數爲關聯的模型對象Info，第二個參數爲一個對象，其包含一個屬性爲foreginKey爲對應的信息表中studentId字段

      在info.js中，使用了belongsTo()方法，第一個參數爲關聯的模型對象Student， 第二個參數也是一個對象，其有兩個屬性，foreginKey爲info表中的"studentId"字段，第二個參數targetKey爲student表中的"id"字段

      總結： hasOne()和belongsTo()第一個參數爲本表關聯的另一個表的Model實例，第二個參數中，都有foreginKey屬性，對hasOne來講，這個屬性值是對方表與本身Id對應的字段，對belongsTo來講，這個屬性值是本表上的與對方表id對應的字段名。belongsTo比hasOne多了個targetKey屬性，其爲對方表的對應主鍵名

    2. 一對多

      classes與student是一對多的關係，一個班級有多個學生，多個學生組成一個班級。

      在student.js中，使用了belongsTo()，在classes.js中，使用了hasMany()，發現hasMany()與belongsTo()所須要的參數是相似的，可是這裏注意，hasMany()裏面的foreginKey值是對方表的classesId。結合第上面"一對一"的分析，咱們能夠總結出：

      has開頭的方法中，foreginKey屬性值從對方的表上找，若是有targetKey的值則是本身的主鍵；

      belongs開頭的方法中，foreginKey屬性值在自身表上找，targetKey屬性值則是對方表上

    3. 多對多

      分析多對多關係，一個學生有多門課，一個課有多個學生，那咱們能夠用一箇中間表lession-student.js作這個聯繫。

      在student.js中，咱們使用了belongsToMany()方法，lession.js文件中也是如此，經過該方法的參數內容，能夠發現其多了一個through屬性，其值是中間表的Model實例。根據上面的規律，belongs開頭的方法裏面foreginKey找本身，otherKey找其餘，因此很容易理解。

    總結： 在Model的實例裏面，重寫Model的associate方法，將關聯的關係放到裏面。

    一對一的方法有：hasOne(Model, {foreignKey:對方,})和belongsTo(Model,{foreignKey:本身,targetKey:對方})

    一對多的方法有： hasMany(Model,{foreignKey:對方, targetKey:本身})和belongsTo(Model,{foreignKey:本身,targetKey:對方})

    多對多的方法有： belongsToMany(Model,{through:Model, targetKey:本身, otherKey:對方})

3.聯表查詢

  • 一對一

    在controller裏面以下寫

    // 獲取學生信息 經過一對多的聯繫
    async info(){
        const { ctx, app } = this;
        let result = await app.model.Student.findAll({
          include: {
            model: app.model.Info
          }
        });
        ctx.body = result;
    }
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    獲取到的值以下：

    [
		// 第一個學生
    {
        "id": 1,
        "number": "160101",
        "password": "202cb962ac59075b964b07152d234b70",
        "classId": 1,
        "createdAt": "2019-05-12 13:16:09",
        "updatedAt": "2019-05-12 13:16:12",
        "deletedAt": null,
        "info": {  // 聯表查到的信息
            "sex": "男",
            "id": 1,
            "name": "許仙",
            "age": 23,
            "studentId": 1,
            "createdAt": "2019-05-12 13:25:58",
            "updatedAt": "2019-05-12 13:26:01",
            "deletedAt": null
        }
    },
  	// 第二個學生
    {
        "id": 2,
        "number": "160201",
        "password": "202cb962ac59075b964b07152d234b70",
        "classId": 2,
        "createdAt": "2019-05-12 13:16:32",
        "updatedAt": "2019-05-12 13:16:35",
        "deletedAt": null,
        "info": {
            "sex": "女",
            "id": 2,
            "name": "白素貞",
            "age": 20,
            "studentId": 2,
            "createdAt": "2019-05-12 13:26:41",
            "updatedAt": "2019-05-12 13:26:46",
            "deletedAt": null
        }
    },
    {
        "id": 3,
        "number": "160102",
        "password": "202cb962ac59075b964b07152d234b70",
        "classId": 1,
        "createdAt": "2019-05-12 13:17:17",
        "updatedAt": "2019-05-12 13:17:21",
        "deletedAt": null,
        "info": {
            "sex": "男",
            "id": 3,
            "name": "法海",
            "age": 22,
            "studentId": 3,
            "createdAt": "2019-05-12 13:27:20",
            "updatedAt": "2019-05-12 13:27:22",
            "deletedAt": null
        }
    },
    {
        "id": 4,
        "number": "160103",
        "password": "202cb962ac59075b964b07152d234b70",
        "classId": 1,
        "createdAt": "2019-05-12 13:17:51",
        "updatedAt": "2019-05-12 13:17:54",
        "deletedAt": null,
        "info": {
            "sex": "女",
            "id": 4,
            "name": "小青",
            "age": 18,
            "studentId": 4,
            "createdAt": "2019-05-12 13:27:48",
            "updatedAt": "2019-05-12 13:27:51",
            "deletedAt": null
        }
    },
    {
        "id": 5,
        "number": "160104",
        "password": "202cb962ac59075b964b07152d234b70",
        "classId": 1,
        "createdAt": "2019-05-12 13:18:13",
        "updatedAt": "2019-05-12 13:18:16",
        "deletedAt": null,
        "info": {
            "sex": "女",
            "id": 5,
            "name": "金如意",
            "age": 20,
            "studentId": 5,
            "createdAt": "2019-05-12 13:28:34",
            "updatedAt": "2019-05-12 13:28:37",
            "deletedAt": null
        }
    },
    {
        "id": 6,
        "number": "160202",
        "password": "202cb962ac59075b964b07152d234b70",
        "classId": 2,
        "createdAt": "2019-05-12 13:18:36",
        "updatedAt": "2019-05-12 13:18:39",
        "deletedAt": null,
        "info": {
            "sex": "男",
            "id": 6,
            "name": "景鬆",
            "age": 23,
            "studentId": 6,
            "createdAt": "2019-05-12 13:30:07",
            "updatedAt": "2019-05-12 13:30:10",
            "deletedAt": null
        }
    }
]
複製代碼

  • 一對多

    // 獲取班級名爲 軟件工程1601 的班級學生
    async student(){
      const { ctx, app } = this;
      let result = await app.model.Classes.findAll({
        where: {
          name: '軟件工程1601'
        },
        include: {
          model: app.model.Student
        }
      })
      ctx.body = result;
    }
複製代碼

    獲取數據以下：

    [
    {
        "id": 1,
        "name": "軟件工程1601",
        "createdAt": "2019-05-12 13:11:43",
        "updatedAt": "2019-05-12 13:11:47",
        "deletedAt": null,
        "students": [
            {
                "id": 1,
                "number": "160101",
                "password": "202cb962ac59075b964b07152d234b70",
                "classId": 1,
                "createdAt": "2019-05-12 13:16:09",
                "updatedAt": "2019-05-12 13:16:12",
                "deletedAt": null
            },
            {
                "id": 3,
                "number": "160102",
                "password": "202cb962ac59075b964b07152d234b70",
                "classId": 1,
                "createdAt": "2019-05-12 13:17:17",
                "updatedAt": "2019-05-12 13:17:21",
                "deletedAt": null
            },
            {
                "id": 4,
                "number": "160103",
                "password": "202cb962ac59075b964b07152d234b70",
                "classId": 1,
                "createdAt": "2019-05-12 13:17:51",
                "updatedAt": "2019-05-12 13:17:54",
                "deletedAt": null
            },
            {
                "id": 5,
                "number": "160104",
                "password": "202cb962ac59075b964b07152d234b70",
                "classId": 1,
                "createdAt": "2019-05-12 13:18:13",
                "updatedAt": "2019-05-12 13:18:16",
                "deletedAt": null
            }
        ]
    }
]
複製代碼

  • 多對多

    從學生獲取課程信息

    // 獲取學生的選課內容
    async lession(){
      const { ctx, app } = this;
      let result = await app.model.Student.findAll({
        where:{
          id: 1,
        },
        include: [
          {model: app.model.Info},
          {model: app.model.Lession}
        ]
      });
      ctx.body = result;
    }
複製代碼

    這裏的話，注意include的值爲一個數組了，這樣能夠多個聯表獲取數據

    數據以下：

    [
    {
        "id": 1,
        "number": "160101",
        "password": "202cb962ac59075b964b07152d234b70",
        "classId": 1,
        "createdAt": "2019-05-12 13:16:09",
        "updatedAt": "2019-05-12 13:16:12",
        "deletedAt": null,
        "info": {
            "sex": "男",
            "id": 1,
            "name": "許仙",
            "age": 23,
            "studentId": 1,
            "createdAt": "2019-05-12 13:25:58",
            "updatedAt": "2019-05-12 13:26:01",
            "deletedAt": null
        },
        "lessions": [
            {
                "id": 1,
                "name": "計算機網絡",
                "createdAt": "2019-05-12 13:12:32",
                "updatedAt": "2019-05-12 13:12:35",
                "deletedAt": null,
                "lession_student": {
                    "lessionId": 1,
                    "studentId": 1,
                    "createdAt": "2019-05-12 13:20:35",
                    "updatedAt": "2019-05-12 13:20:40",
                    "deletedAt": null
                }
            },
            {
                "id": 2,
                "name": "Java程序設計",
                "createdAt": "2019-05-12 13:12:50",
                "updatedAt": "2019-05-12 13:12:52",
                "deletedAt": null,
                "lession_student": {
                    "lessionId": 2,
                    "studentId": 1,
                    "createdAt": "2019-05-12 13:23:10",
                    "updatedAt": "2019-05-12 13:23:13",
                    "deletedAt": null
                }
            },
            {
                "id": 3,
                "name": "軟件項目管理",
                "createdAt": "2019-05-12 13:13:07",
                "updatedAt": "2019-05-12 13:13:10",
                "deletedAt": null,
                "lession_student": {
                    "lessionId": 3,
                    "studentId": 1,
                    "createdAt": "2019-05-12 13:24:21",
                    "updatedAt": "2019-05-12 13:24:24",
                    "deletedAt": null
                }
            }
        ]
    }
]
複製代碼

    從課程獲取選課學生：

    // 獲取某個課的參課學生
    async lessionStudent(){
      const { ctx, app } = this;
      let result = await app.model.Lession.findAll({
        where:{
          name: '網絡安全'
        },
        include: {
          model: app.model.Student,
          include: {
            model: app.model.Info
          }
        }
      });
      ctx.body = result;
    }
複製代碼

    這裏注意，在include的下面又有一個include，第二個include是相對Student表的

    數據以下：

    [
    {
        "id": 4,
        "name": "網絡安全",
        "createdAt": "2019-05-12 13:13:22",
        "updatedAt": "2019-05-12 13:13:25",
        "deletedAt": null,
        "students": [
            {
                "id": 2,
                "number": "160201",
                "password": "202cb962ac59075b964b07152d234b70",
                "classId": 2,
                "createdAt": "2019-05-12 13:16:32",
                "updatedAt": "2019-05-12 13:16:35",
                "deletedAt": null,
                "lession_student": {
                    "lessionId": 4,
                    "studentId": 2,
                    "createdAt": "2019-05-12 13:24:59",
                    "updatedAt": "2019-05-12 13:25:03",
                    "deletedAt": null
                },
                "info": {
                    "sex": "女",
                    "id": 2,
                    "name": "白素貞",
                    "age": 20,
                    "studentId": 2,
                    "createdAt": "2019-05-12 13:26:41",
                    "updatedAt": "2019-05-12 13:26:46",
                    "deletedAt": null
                }
            },
            {
                "id": 6,
                "number": "160202",
                "password": "202cb962ac59075b964b07152d234b70",
                "classId": 2,
                "createdAt": "2019-05-12 13:18:36",
                "updatedAt": "2019-05-12 13:18:39",
                "deletedAt": null,
                "lession_student": {
                    "lessionId": 4,
                    "studentId": 6,
                    "createdAt": "2019-05-12 13:25:12",
                    "updatedAt": "2019-05-12 13:25:15",
                    "deletedAt": null
                },
                "info": {
                    "sex": "男",
                    "id": 6,
                    "name": "景鬆",
                    "age": 23,
                    "studentId": 6,
                    "createdAt": "2019-05-12 13:30:07",
                    "updatedAt": "2019-05-12 13:30:10",
                    "deletedAt": null
                }
            }
        ]
    }
]
複製代碼

4. 總結

用時4小時，調試加數據庫設置，代碼編寫，查文檔。容許我偷個懶，不想總結了，仔細閱讀內容，基本上能夠了解Sequelize在聯表查詢上的基本用法了

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