Sails Waterline SQL join in populate

Question

Waterline是否支持执行SQL join(除了query())？我已经在模型中设置了关联，但实际生成的SQL查询是循环select语句。目前是否只支持"n+1 selects"？我是不是缺少某个配置选项？

下面是一个循环select语句的1->Many填充示例：(sails/waterline/sails-mysql v0.10.0-rc8)

/**
* City.js
*/
module.exports = {
"adapter": "someMysqlServer",
"tableName": "city",
autoCreatedAt: false,
autoUpdatedAt: false,
schema: true,
attributes: {
    "id": {
        "type": "integer",
        "primaryKey": true,
        "autoIncrement": true,
        "columnName": "ID"
    },
    "Name": {
        "type": "string",
        "maxLength": 35
    },
    "District": {
        "type": "string",
        "maxLength": 20
    },
    "Population": {
        "type": "integer"
    },
    "CountryCode": {
        //a city has one country
        "model": "Country"
    }
}};




/**
* Country.js
*/

module.exports = {
  "adapter": "someMysqlServer",
  "tableName": "country",
  autoCreatedAt: false,
  autoUpdatedAt: false,
  schema: true,
  attributes: {
      "id": {
          "type": "string",
          "required": true,
          columnName: "Code",
          "primaryKey": true,
          "maxLength": 3
      },
      "Name": {
          "type": "string",
          "maxLength": 52
      },
      Continent: "string",
      "Region": {
          "type": "string",
          "maxLength": 26
      },
      SurfaceArea: "float",
      IndepYear: "integer",
      Population: "integer",
      LifeExpectancy: "float",
      GNP: "float",
      GNPOld: "float",
      LocalName: "string",
      GovernmentForm: "string",
      HeadOfState: "string",
      Capital: "integer",
      Code2: "string",
      Cities: {
          //country has many cities
          "collection": "City",
          "via": "CountryCode"
      }
  }
};

然后，当我导航到http://localhost:1337/country?populate=[Cities]时，我的日志显示执行了以下sql：

SELECT `country`.`Name`, `country`.`Continent`, `country`.`Region`, `country`.`SurfaceArea`, `country`.`IndepYear`, `country`.`Population`, `country`.`LifeExpectancy`, `country`.`GNP`, `country`.`GNPOld`, `country`.`LocalName`, `country`.`GovernmentForm`, `country`.`HeadOfState`, `country`.`Capital`, `country`.`Code2`,`country`.`Code` FROM `country` LIMIT 30 OFFSET 0
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ABW' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='AFG' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='AGO' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='AIA' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ALB' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='AND' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ANT' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ARE' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ARG' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ARM' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ASM' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ATA' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ATF' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='ATG' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='AUS' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='AUT' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='AZE' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BDI' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BEL' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BEN' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BFA' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BGD' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BGR' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BHR' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BHS' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BIH' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BLR' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BLZ' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BMU' LIMIT 30
SELECT `city`.`Name`, `city`.`CountryCode`, `city`.`District`, `city`.`Population`, `city`.`ID` FROM `city` WHERE `city`.`CountryCode`='BOL' LIMIT 30

Answer 1

测试版中的.populate()实现被有意简化，以支持尽可能广泛的适配器集。在最终的v0.10版本中，受支持的“核心”SQL适配器(sails-mysql和sails-postgresql)将执行实际的连接。