many-to-many

问题 After trying for few hours I can not save to the database. The context is this: I have two types of users, one for that I only need very basic information [Username, email, password] and another kind of user for who I need a lot of information [age, gender, city and so on] I did not use STI becouse of the vast quantity of Null values there would be in the table. So I created this three modes in which a user has a profile (profiles table) or not depending of its type [1 or 2], and a field of

问题 Searched everywhere but couldn't find anything even though it feels so simple. So basically i have two classes in my models.py class Restaurant(models.Model): restaurant_title = models.CharField(max_length=30) location = CountryField(null=True, blank_label='(select country)') first_purchase_discount = models.BooleanField(default=False) updated = models.DateTimeField(auto_now=True) slug = models.SlugField(max_length=30, unique=True) def save (self, *args, **kwargs): self.slug = slugify(self

问题 Hi I'm trying to select records from one table which doesn't have records in connected many-to-many table with specific values. I will explain on sample tables: documentation: id_documentation irrelevant_data user: id_user irrelevant_data documentation_user: id_documentation id_user role What I want to achieve is to select every single documentation which doesn't have user in specific role. Any ideas? The main problem is that I'm using java's CriteriaBuilder to create query so using

问题 I've already read this, this and this, but I cant make this SQL work: INSERT INTO main_phrase (description) VALUES ('Mot commun féminin pluriel animaux'); /* ERROR: */ WITH t1 AS ( SELECT id FROM main_phrase WHERE description='Mot commun féminin pluriel animaux' ), t2 AS ( SELECT id FROM main_groupecategories WHERE description='Mot commun féminin pluriel animaux' ) INSERT INTO main_phrasegroupecategories (phrase_id, groupe_categories_id) VALUES (t1.id, t2.id); I get: ERROR: missing entry for

问题 I have 2 domain class with a many to many relationship. When I delete the entity that belongs to the other, I have to remove the relation before in order to avoid a foreign key error. I would like to put this code in the beforeDelete event, but I obtain a problem with optimistc locking. This is the code of the domain classes: class POI { static belongsTo = [Registration]; static hasMany = [registrations: Registration] def beforeDelete = { def poiId = this.id POI.withNewSession { session ->

问题 In my Django app I have the following models.py: from django.db import models import datetime class Job(models.Model): name = models.CharField(max_length = 250, null = False) user = models.CharField(max_length = 30, null = False) command = models.CharField(max_length = 1000, null = False) whenToRun = models.DateTimeField('Run Date', null = False) output = models.CharField(max_length = 100000, null = True) class Host(models.Model): jobs = models.ManyToManyField(Job, blank = True) name = models

问题 Ok, so i have this problem right now. I have 2 Models like so: public class Contact: BaseModel { public string LastName { get; set; } public string FirstMidName { get; set; } public string Adress { get; set; } public int UserID { get; set; } [Display(Name = "Full Name")] public string FullName { get { return FirstMidName+ " " + LastName; } } public virtual List<Group> Groups { get; set; } public virtual User User { get; set; } public virtual ICollection<Phones> Phones { get; set; } } and also

问题 I'm trying to set up a many-to-many relationship in SSAS Tabular. I've got the following in my tabular project (sales, customers, customer emails): A sale is tied to a customer. A customer can have multiple emails. How would I create a list of all emails that fit the current filter of a pivot table? For example, I could create a pivot table shows "accounts with margin < 20%", and want a list of all emails associated with those accounts. Sample, starting with the following sales data: customer

问题 I have a standard many-to-many relationship set up. Entity A can have many of Entity B, and vice versa . I'm trying to get a list of all Entity A that do NOT have any corresponding Entity B. In SQL, I'd run a query like this: SELECT a.* FROM entity_a a LEFT JOIN a_b r ON r.AID = a.id WHERE r.BID IS NULL In this query, a_b is the linking table. I'm trying to write a DQL statement (or use some other method) to get the same result, but the following does not work: SELECT s FROM VendorMyBundle

问题 Guys I am trying to make a simple ticket generation system for my company as a favor. For now, I have a table called tblTicket and another table called tblEngineer in my MSSQL database. My application is in C# windows forms, so on the new ticket generation form, I have many textboxes and a comboBox for assigning engineer which is being populated by tblEngineer . Upon ticket generation, all the information entered in this form is stored in tblTicket along with EngineerID from tblEngineer . It