續集連接兩個不關聯的表

Question

我想通過連接兩個不使用關係「關聯」的表來檢索數據。這兩個表如下所示：

mysql> desc partner_txns; 
+------------+-------------+------+-----+---------+----------------+ 
| Field  | Type  | Null | Key | Default | Extra   | 
+------------+-------------+------+-----+---------+----------------+ 
| id   | int(11)  | NO | PRI | NULL | auto_increment | 
| txn_id  | int(11)  | NO |  | NULL |    | 
| user_id | int(11)  | NO | MUL | NULL |    | 
| txn_type | varchar(1) | YES |  | NULL |    | 
| txn_amnt | double  | YES |  | NULL |    | 
| desc  | varchar(64) | YES |  | NULL |    | 
| createdBy | int(11)  | NO | MUL | NULL |    | 
| created_on | datetime | NO |  | NULL |    | 
+------------+-------------+------+-----+---------+----------------+ 
8 rows in set (0.00 sec) 

mysql> desc accounts_master; 
+-------------+-------------+------+-----+---------+----------------+ 
| Field  | Type  | Null | Key | Default | Extra   | 
+-------------+-------------+------+-----+---------+----------------+ 
| id   | int(11)  | NO | PRI | NULL | auto_increment | 
| name  | varchar(64) | NO |  | NULL |    | 
| owner  | int(11)  | NO | MUL | NULL |    | 
| type  | int(11)  | YES |  | 0  |    | 
| expires_on | datetime | NO |  | NULL |    | 
| max_lists | int(11)  | YES |  | 10  |    | 
| max_groups | int(11)  | YES |  | 10  |    | 
| createdBy | int(11)  | NO | MUL | NULL |    | 
| modifiedBy | int(11)  | NO | MUL | NULL |    | 
| created_on | datetime | NO |  | NULL |    | 
| modified_on | datetime | NO |  | NULL |    | 
+-------------+-------------+------+-----+---------+----------------+ 
11 rows in set (0.00 sec) 

不使用sequelize，通常我會做一個SQL查詢是這樣的：

mysql> select a.user_id, b.name from partner_txns a, accounts_master b where a.createdBy = 3 and a.user_id = b.owner; 
+---------+-------------+ 
| user_id | name  | 
+---------+-------------+ 
|  8 | New account | 
|  8 | Comviva  | 
|  8 | Infosys  | 
|  9 | HDFC  | 
|  9 | INTEGRA  | 
+---------+-------------+ 
5 rows in set (0.00 sec) 

什麼是做這個用Sequelize相當於，假設我有這兩個表作爲兩種型號如下：

• PartnerTxn
• 帳戶

我很想使用像：

var Model = require('ecp_model'); 

Model.PartnerTxn.findAll({ 
    where: {createdBy:3 }, 
    include : [{model:Model.Account, attribute:['name']}] 
}).then(function(results) { 
    console.log("results:", results); 
}); 
[rv.nath@localhost authserver]$ 

但隨後這是行不通的，因爲這兩個表都沒有關係。所以，我得到一個錯誤如下：

Unhandled rejection Error: Account is not associated to PartnerTxn! 
    at validateIncludedElement (/var/opt/ecp_db/node_modules/sequelize/lib/model.js:569:11) 
    at /var/opt/ecp_db/node_modules/sequelize/lib/model.js:452:29 
    at Array.map (native) 
    at validateIncludedElements (/var/opt/ecp_db/node_modules/sequelize/lib/model.js:448:37) 
    at null.<anonymous> (/var/opt/ecp_db/node_modules/sequelize/lib/model.js:1360:32) 
    at tryCatcher (/var/opt/ecp_db/node_modules/bluebird/js/release/util.js:16:23) 
    at Promise._settlePromiseFromHandler (/var/opt/ecp_db/node_modules/bluebird/js/release/promise.js:503:31) 
    at Promise._settlePromise (/var/opt/ecp_db/node_modules/bluebird/js/release/promise.js:560:18) 
    at Promise._settlePromise0 (/var/opt/ecp_db/node_modules/bluebird/js/release/promise.js:605:10) 
    at Promise._settlePromises (/var/opt/ecp_db/node_modules/bluebird/js/release/promise.js:684:18) 
    at Async._drainQueue (/var/opt/ecp_db/node_modules/bluebird/js/release/async.js:126:16) 
    at Async._drainQueues (/var/opt/ecp_db/node_modules/bluebird/js/release/async.js:136:10) 
    at Immediate.Async.drainQueues [as _onImmediate] (/var/opt/ecp_db/node_modules/bluebird/js/release/async.js:16:14) 
    at processImmediate [as _immediateCallback] (timers.js:383:17) 

Answer 1

我知道這是將近一年之後，但在任何情況下，在您的情況，並尋找正確的答案。

當您有兩個單獨的數據類型由第三個錶鏈接時，您正在尋找Sequelize的BelongToMany（Through）。

所以在你的情況下，你需要定義第三個模型：UserMaster。您將授予UserMaster兩個屬性：user_id（與PartnerTxn屬性相同）和所有者（與Account屬性相同）。

然後你可以這樣做：

Account.belongsToMany(PartnerTxn, {through: 'UserMaster'}); 
PartnerTxn.belongsToMany(Account, {through: 'UserMaster'}); 

爲了進一步參考，documentation有信息。