many-to-many

I'm using POCOs in combination with EF4 and some entities are in many-to-many relationships, in my case objects of class User and objects of class PrivilegeGroup. This is how class User looks like: public class User { public int UserID { set; get; } public string UserName { get; set; } public string UserPassword { get; set; } public bool IsActive { get; set; } public List<PrivilegeGroup> PrivilegeGroups { get; set; } } And this is how class PrivilegeGroup looks like: public class PrivilegeGroup { public int PrivilegeGroupID { get; set; } public string Name { get; set; } public List<User> Users

hoping someone can help me out with this. I'm trying to figure out whether I can construct a query that will allow me to retrieve items from my db based on a ForeignKey field and a ManyToManyField at the same time. The challenging part is that it will need to filter on multiple ManyToMany objects. An example will hopefully make this clearer. Here are my (simplified) models: class Item(models.Model): name = models.CharField(max_length=200) brand = models.ForeignKey(User, related_name='brand') tags = models.ManyToManyField(Tag, blank=True, null=True) def __unicode__(self): return self.name class

I am mapping an idea for a relationship using Core Data. I have an Employer entity who has a many-to-many relationship with Employees . Basically, an employee can work for multiple employers, and an employer can have multiple employees. The problem I'm facing is, I'm not sure how to manage the contracts between employees and employers. As an employee can work for either 1 or many employers, they would naturally have a contract for each employer they work for (complete with salary, duration) and a list of dates when they are working for a specific employer. My question is - how to manage the

I have two tables. Table A and Table B . Both are connected with a many-to-many relationship. Table A: ID --- 1 2 Table B: ID --- 3 4 Table AB: ID | A_ID | B_ID ---------------- 5 | 1 | 4 6 | 1 | 3 7 | 2 | 3 I want to get the list of ID s from table B which have a relation to a list of ID s of table A . Example from the above tables: I want to get all B s which have a relation to table A ID 1 and ID 2. I get then ID 3 has to both ID s of table A . How could I do this with an SQL query ? If you are looking to select based on a list of As (not ALL As), then do it like this: SELECT b_id FROM ab

I'm use sqlalchemy 0.6.4. I have 2 classes: Question and Tag, they are many-to-many. class Question(Base): __tablename__ = "questions" id = Column(Integer, primary_key=True) deleted = Column(Boolean) ... tags = relationship('Tag', secondary=r_questions_tags) class Tag(Base): __tablename__ = "tags" id = Column(BigInteger, primary_key=True) questions = relationship('Question', secondary=r_questions_tags) So, tag.questions will get all the questions belong to a tag. But now, since the Question has a deleted column, I hope to do like this: class Tag(Base): ... # get non-deleted questions questions