[英]How can I get data from a child collection in mongodb?
我需要在以下json
字符串中填充“任务”。
{
"sectionname": "Section1",
"tasks": [],
"_id": "5d46e5c4d2e87911d8d4d42c",
"projectid": "5d46d42333aecb0b6aa3f2ca",
"userid": "5d46b54635bb9e05b9d33528",
"time": "2019-08-04T14:03:48.953Z",
"__v": 0
},
它当前包含3个集合(不包括“用户帐户”集合)
我可以通过简单的“查找”请求从“部分”和“项目”中获取数据。 例如:
userProjectSections.find({userid: req.user, projectid: req.params.id})
然后,我决定添加.populate('tasks')
,但是它没有任何改变。 任务仍然为空[]。
这是完整的模型。
const userProjects = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
time : { type : Date, default: Date.now },
complete : { type : Boolean, default: false },
userid: {type: String, ref: 'user'},
projectname: {type: String, default: 'New Project'}
});
module.exports = mongoose.model('Projects', userProjects);
const userProjectSections = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
time : { type : Date, default: Date.now },
complete : { type : Boolean, default: false },
userid: {type: String, ref: 'user'},
projectid: {type: String, ref: 'Projects'},
sectionname: {type: String, default: 'New Section'},
tasks: [{ type: Schema.ObjectId, ref: 'SectionTasks' }]
});
module.exports = mongoose.model('ProjectSection', userProjectSections);
const userSectionTasks = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
time : { type : Date, default: Date.now },
complete : { type : Boolean, default: false },
userid: {type: String, ref: 'user'},
projectid: {type: String, ref: 'Projects'},
sectionid: {type: String, ref: 'ProjectSection'},
task: {type: String, default: 'New task'}
});
module.exports = mongoose.model('SectionTasks', userSectionTasks);
从理论上讲,我可以从React frontend
编写另一个API调用,但我更希望从单个请求中获取数据并包含任务。
结束了杀害const userSectionTasks
,而是增加了额外的阵列, Tasks
到常量userProjectSections
,像这样
tasks: [{
_id: mongoose.Schema.Types.ObjectId,
task: String,
postedBy: {
type: mongoose.Schema.Types.ObjectId,
ref: 'user'
}
}]
现在,我可以简单地使用$addToSet
向该部分添加新任务。
干杯!
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