與 Sequelize 的嵌套關系

Question

我在 Node + MySQL 中使用 Sequelize。

我有一個與此類似的模型結構：

// models:
var Group, Issue, Invite;

// many Issues per Group
Group.hasMany(Issue);
Issue.belongsTo(Group);

// Groups can invite other Groups to work on their Issues
Issue.hasMany(Invite, {foreignKey: groupId});
Invite.belongsTo(Issue, {foreignKey: groupId});
Group.hasMany(Invite, {foreignKey: inviteeId});
Invite.belongsTo(Group, {foreignKey: inviteeId});

// given an Issue id, include all Invites + invited Groups (inviteeId) - But how?
var query = {
    where: {id: ...}, 
    include: ???
};
Issue.find(query).complete(function(err, issue) {
    var invites = issue.invites;
    var firstInvitedGroup = issue.invites[0].group;
    // ...
});

這是可能嗎？ 什么是可能的解決方法？ 謝謝！

Answer 1

Sequelize Docs: Nested Eager Loading

例子

Issue.find({
    include: [
        {
            model: Invite,
            include: [Group]
        }
    ]
});

Answer 2

如果您想預先加載所有嵌套關聯，請使用此功能。

Issue.find({
    include:getNestedAssociations(Issue)
});



//Recursively load all bested associtiaons
function getNestedAssociations(_model) {
  const associations = [];
  for (const association of Object.keys(_model.associations)) {
    const model = _model.associations[association].target;
    const as = association;
    const include = getNestedAssociations(model);
    associations.push({
      model: model,
      as: as,
      ...(include && { include: include }),
    });
  }
  return associations;
}

Answer 3

在失去了所有希望之后，我終於嘗試了一個有效的隨機命中 snd。 只需發送帶有空數組的屬性，然后它就不會包含在結果中

{
    model: User,
    as: 'users',
    attributes: [],  // This will work//
    where: {
      user_id: 1
    }
  }