Question

外键上的注释返回外键。如何从查询中获取对象本身？在以下示例中，“the_user”是“投票”模型中的外键：

Vote.objects.values('the_user').annotate(vote_count=Count('the_user')).order_by('-vote_count')

它将返回

[{'the_user': 4, 'vote_count': 12} , {'the_user': 6, 'vote_count': 2}]

但我需要用户自己的对象..不是ids

Answer 1

values()完全相同 - 返回值，使用通常的查询集

Vote.objects.annotate(vote_count=Count('the_user')).order_by('-vote_count')

然后该查询集中的每个对象都将具有vote_count属性。

Answer 2

您应始终在模型中查询要在结果查询集中返回哪些对象，因此在您的情况下：

'use strict';

let pgp = require('pg-promise')();
let db = pgp("postgres://username:password@server:5432/db");
let localdb = pgp("postgres://username:password@server:5432/db");
var mssql = require('mssql');

let start = new Date();
db.query('select * from logs').then((result) => {
    console.log("Postres (RDS) query duration: " + (new Date() - start) + "ms");
    console.log("Postres (RDS) rows returned: " + result.length);
    console.log("");

    let localstart = new Date();
    localdb.query('select * from logs').then((localresult) => {
        console.log("Postgres (Local) query duration: " + (new Date() - localstart) + "ms");
        console.log("Postgres (Local) rows returned: " + localresult.length);
        console.log("");

        var config = {
            user: 'username',
            password: 'password',
            server: 'server', // You can use 'localhost\\instance' to connect to named instance 
            database: 'db'
        };

        mssql.connect(config).then(function () {

            // Query 
            let localMSSqlStart = new Date();
            new mssql.Request().query('select TOP 50000 * from dbo.AppLog ORDER BY 1 DESC').then(function (recordset) {
                console.log("MSSQL (local) query duration: " + (new Date() - localMSSqlStart) + "ms");
                console.log("MSSQL (local) rows returned: " + result.length);
                console.log("");
            }).catch(function (err) {

                // ... query error checks
                console.log("Problem querying MSSQL: " + err);
            });
        }).catch(function (err) {

            // ... connect error checks 
            console.log("Problem connecting to MSSQL: " + err);
        });
    });
});

Answer 3

获取外键而不是用户对象的原因是因为使用了values（），值返回dict而不是模型对象。使用select_related而不是值，这将解决您的问题。

Django：如何在注释中获取对象而不仅仅是外键？

3 个答案: