我正在为学校平台开发API。我想在我还在开发的时候，在引导脚本中迁移和种子数据库。
我可以创建学校实例、组实例和个人实例，但我不知道如何添加个人实例和组实例之间的关系（多对多）
这是我的Person.json文件：
{
"name": "Person",
"base": "User",
"strict": true,
"idInjection": true,
"properties": {
"name": {
"type": "string",
"required": true
},
"firstName": {
"type": "string",
"required": true
}
},
"validations": [],
"relations": {
"groups": {
"type": "hasAndBelongsToMany",
"model": "Group"
},
"school": {
"type": "belongsTo",
"model": "School"
}
},
"acls": [],
"methods": []
}
这是我的group.json文件
{
"name": "Group",
"base": "PersistedModel",
"strict": true,
"idInjection": true,
"properties": {
"name": {
"type": "string",
"required": true
}
},
"validations": [],
"relations": {
"people": {
"type": "hasAndBelongsToMany",
"model": "Person"
},
"school": {
"type": "belongsTo",
"model": "School"
}
},
"acls": [],
"methods": []
}
这是我的启动脚本：
var async = require('async');
module.exports = function(app) {
var mysqlDs = app.dataSources.mysqlDs;
var boysNames = ["Lucas", "Liam", "Arthur", "Vince", "Noah", "Finn", "Mathis", "Louis", "Adam", "Jules", "Lars", "Seppe", "Stan", "Alexander", "Leon", "Kobe", "Victor", "Matteo", "Milan", "Mats", "Vic", "Wout", "Daan", "Senne", "Ferre", "Tuur", "Nathan", "Elias", "Warre", "Jack", "Felix", "Cas", "Thomas", "Lowie", "Robbe", "Lewis", "Rayan", "Nand", "Sem", "Maxim", "Emiel", "Jasper", "Oscar", "Mauro", "Sam", "Mohamed", "Luca", "Bent", "Ruben", "Simon", "Imran", "Jayden", "Lou", "Viktor", "Bas", "Lenn", "Rune", "Lukas", "Eden", "Emile"];
var girlsNames = ["Emma", "Louise", "Elise", "Ella", "Marie", "Noor", "Lena", "Julie", "Lotte", "Olivia", "Anna", "Elena", "Mila", "Lore", "Fien", "Nina", "Lina", "Nora", "Laura", "Juliette", "Charlotte", "Lisa", "Amber", "Amélie", "Fleur", "Renée", "Lily", "Sara", "Camille", "Hanne", "Luna", "Liv", "Roos", "Helena", "Sarah", "Sofia", "Janne", "Noa", "Jade", "Nore", "Fenna", "Axelle", "Kato", "Alice", "Aya", "Jana", "Lize", "Paulien", "Amelie", "Lucie", "Lara", "Zoë", "Mona", "Manon", "Leonie", "Ines", "Oona", "Laure", "Mira", "Febe"];
var names = ["Jong","Jansen","Vries","Visser","Jans","Bakker","Dijk","Vos","Smit","Berg","Boer","Groot","Janssen","Jacobs","Veen","Bos","Bergman","Hendriks","Dekker","Mulder","Willems","Meijer","Graaf","Leeuwen","Vermeulen","Koster","Peeters","Brouwer","Kok","Peters","Smits","Linden","Vliet","Wit","Beekman","Bosch","Meer","Koning","Beek","Haan","Vermeer","Verhoeven","Bruijn","Jonge","Heuvel","Martens","Dam","Hoek","Pieters","Walle","Bruin","Timmermans","Prins","Wouters","Janssens","Blom","Velde","Loon","Lange","Maas","Mol","Dijkstra","Post","Wal","Maes","Dieleman","Hermans","Jager","Stam","Gerrits","Groen","Roos","Wijk","Kuiper","Broek","Leeuw","Lambert","Kroon","Verdonck","Geerts","Boon","Hoekstra","Schouten","Gastel","Brink","Goossens","Steen","Bleijenberg","Bijl","Dubois","Jonker","Rooij","Driel","Pol","Ruiter","Stevens","Horst","Verbeek","Mertens","Ende","Sanders","Driessen","Huisman","Kooij","Schipper","Waal","Laan","Scholten","Vink","Ven","Postma","Aerts","Santen","Roovers","Verhulst","Verschoor","Ham","Moerman","Rijn","Bax","Franken","Eijk","Martin","Bosman","Meulen","Veenstra","Mostert","Velden","Harms","Wolters","Zanten","Claes","Poot","Ridder","Ginkel","Doorn","Heijden","Oost","Os","Blok","Kramer","Simons","Kuipers","Rovers","Cornelis","Dupont","Valk","Zwart","Gerard","Verweij"]
//first lets recreate all databases
mysqlDs.automigrate(function(){
console.log("tables recreated: let's seed");
async.parallel({
schools: async.apply(createSchools)
// ....
}, function(errFase1, resultsFase1) {
if (errFase1) throw errFase1;
async.parallel({
groups: async.apply(createGroups, resultsFase1.schools),
persons: async.apply(createStudents, resultsFase1.schools),
}, function(errFase2, resultsFase2) {
if (errFase2) throw errFase2;
// ???????????????????????????????????
// ??? HOW TO add a relation between the persons and the groups
// a person must be able to live
// in multiple groups
});
});
});
function createSchools(cb) {
var School = app.models.School;
School.create([
{
"name": "Harvard",
"address": "xxx",
"zip": "0000",
"place": "yyy"
},
{
"name": "Oxford",
"address": "xxx",
"zip": "0000",
"place": "yyy"
}
], cb);
}
function createGroups(schools,cb) {
var Group = app.models.Group;
Group.create([
{ "name": "Class 1", "schoolId": schools[0].id },
{ "name": "Class 2", "schoolId": schools[0].id },
{ "name": "Class 3", "schoolId": schools[0].id },
{ "name": "Class 4", "schoolId": schools[0].id },
{ "name": "Class 5", "schoolId": schools[0].id },
{ "name": "Class 6", "schoolId": schools[0].id },
{ "name": "Class 1", "schoolId": schools[1].id },
{ "name": "Class 2", "schoolId": schools[1].id },
{ "name": "Class 3", "schoolId": schools[1].id },
{ "name": "Class 4", "schoolId": schools[1].id },
{ "name": "Class 5", "schoolId": schools[1].id },
{ "name": "Class 6", "schoolId": schools[1].id },
], cb);
}
function createStudents(schools,cb) {
var Person = app.models.Person;
var students = [];
for (var i = 0; i < 240; i++) {
chooseFrom = (i%2 == 1) ? girlsNames : boysNames ;
students.push({
"name": names[i%names.length],
"firstName": chooseFrom[i%chooseFrom.length],
"username": "student"+i,
"password": "testje",
"email": "student"+i+"@mailinator.com",
"emailVerified": true,
"schoolId": schools[Math.floor(i/120)].id
});
};
Person.create(students, cb);
}
};
为了将学生加入小组，我预计会有这样的事情：
Group.findOne(function(err, group){
console.log(group);
group.people().add(students[0].id);
})
我找不到任何关于这个特定问题的教程。
我调试了引导脚本，并检查了组变量，它是一个ModelConstructor。我想我可以通过people（）函数获取相关人员，但如何将一个人添加到特定的组中？
找到了正确的文档：
http://apidocs.strongloop.com/loopback-datasource-juggler/#relationmixin-hasandbelongtomany
//需要传递id，而不是整个实例。即使是loopbackjs文档也需要更新
var student = students[0];
Group.findOne(function(err, group){
console.log(group);
group.people.add(student.id); // <--- id and not instance
})