many-to-many

I am using EF5 and when the the relationship is 1:N, if I want to load related entities I do the following: With T-SQL I load from database the main entities with a T-SQL like that: select * from MainEntities where ... with T-SQL I load the related entities select * from RelatedEntities where IDMainEntity IN (---) At this point EF populate the property navigation of the main entities with the related entities. Also, in the local property of the type of each entity in the dbContext I have all the entities of each type. However, if i do the same with a N:N relationship, I don't have the entity

I have a query that requires to filter exactly 2 authors with the ID Theoretically, Book.objects.filter(author__id=1, author__id=2). which is not possible. How can I solve this problem? Cheers, Mickey Not intuitive at first but the answer is right in front of us. Book.objects.filter(author__id=1).filter(author__id=2) If you want an exact match, you could potentially further filter this result by those items that only have exactly 2 authors. Book.objects.annotate(count=Count('author')).filter(author__id=1)\ .filter(author__id=13).filter(count=2) If you want exact matches dynamically, how about

in an relational database, i have an user table, an category table and an user-category table which do many to many relationship. What's the better form of have this structure in redis? With Redis, relationships are typically represented by sets. A set can be used to represent a one-way relationship, so you need one set per object to represent a many-to-many relationship. It is pretty useless to try to compare a relational database model to Redis data structures. With Redis, everything is stored in a denormalized way. Example: # Here are my categories > hmset category:1 name cinema ... more

I have two entities with a fairly standard Many to Many relationship that I created in EF 5 Code First. These are Service and ServiceItem. The Service entity contains a collection of ServiceItems and the ServiceItem contains a collection of Services. I can create, change and save data to either of the entities basic properties with no problems. When I try to add a ServiceItem to a Service or a Service to a ServiceItem it seems to work, but nothing is saved. I have verified that all the proper database tables are created, including a ServiceItemService table with the cross keys. The database