how to join 4 or more tables in sequelize?

问题

I am rewriting an app , with existing database using sequelize. I have converted existing table, to models in sequelize as below. I have employee table, and access type model, which has read, write, or both in an admin access. all of these access are tracked for employee in and employee access table. but there is a employee group table also, which keeps track , if employee belongs to a particular group and their access type. how do i query using sequelize , to get particular employee access list from employeeAccess table, and also if it belongs to group and if it does access type of that group. so essentially, need to query by joining 4 tables - employee, employee access, employee group and then access type table.

employee model

    var employee = db.seq.define('Employee',{
        id: { type: db.Sequelize.INTEGER},
        managerId: { type: db.Sequelize.INTEGER}, 
        employee_name: { type: db.Sequelize.STRING} ...
    });
    employee.hasOne(address);
    employee.belongsTo(employee, { foreignKey: 'managerId', as: 'Manager' });

address model

    var adress= db.seq.define("Adresss",{
        employee_id: { type: db.Sequelize.INTEGER}...
    });
    address.belongsto(employee);

accessType model

    var accessType = db.seq.define('AccessType ',{
        id: { type: db.Sequelize.INTEGER},
        type: { type: db.Sequelize.STRING}....
    });
    accessType.hasMany(employeeGroup );
    accessType.hasMany(employeeAccess);

EmployeeGroup model

    var EmployeeGroup = db.seq.define('EmployeeGroup ',{
        id: { type: db.Sequelize.INTEGER},
        access_type_id: { type: db.Sequelize.INTEGER},
        employee_id: { type: db.Sequelize.INTEGER} ...
    });
    EmployeeGroup .belongsto(employee);
    EmployeeGroup .belongsto(accessType );

employeeAccess model

    var employeeAccess = db.seq.define('employeeAccess ',{
        id: { type: db.Sequelize.INTEGER},
        access_type_id: { type: db.Sequelize.INTEGER},
        employee_id: { type: db.Sequelize.INTEGER} ...
    });
    employeeAccess.belongsto(employee); 
    employeeAccess.belongsto(accessType );

sql

select * from employeeAcess as a 
left outer join employeeGroup as g 
on a.access_type_id = g.access_type_id 
left outer join accesstype as t 
on g.access_type_id = t.id 
where a.employee_id = 1 and g.employee_id = 1;

回答1:

Try something like this:

const employeeItem = await employee .findById(1, {
  include: [{ 
    model: employeeGroup,
    include: [accessType]
  }, employeeAccess],
  where: {
    '$employeeGroup.access_type_id$': sequelize.col('employeeAccess.access_type_id')
  }
}

来源：https://stackoverflow.com/questions/64947004/how-to-join-4-or-more-tables-in-sequelize

标签

node.js

sequelize.js