mysql - Sequelize连接两个不相关的表

Question

我正在尝试通过连接两个未使用关系“关联”的表来检索数据。这两张表如下:

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)

如果不使用 sequelize，通常我会像这样进行 SQL 查询:

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)

假设我将这两个表作为以下两个模型，那么使用 Sequelize 执行此操作的等效项是什么:

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我很想像这样使用:

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]$ 

但是这将不起作用，因为这两个表不相关。所以，我收到如下错误:

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

我知道这已经快一年了，但以防万一有人遇到你的情况并正在寻找正确的答案。

当您有两个单独的数据类型由第三个表链接时，您正在寻找 Sequelize 的 BelongToMany(Through)。

因此，在您的情况下，您需要定义第三个模型:UserMaster。您可以为 UserMaster 提供两个属性:user_id(与 PartnerTxn 属性相同)和 owner(与 Account 属性相同)。

然后你会这样做:

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

要进一步引用，documentation有信息。