many-to-many

问题 i'm working with doctrine & i have some problem in many-to-many self referencing which has some extra fields. lets describe my scenario : i have a table named Drug , drugs can have conflicts with each other & this conflicts may appear under some conditions & may have some solutions. i've read doctrine documents about many-to-many relations & it's mentioned that it's not good for JoinTable to have some extra fileds. so what's the best solution for this problem? here is my solution, but i'm not

问题 I have a manyToMany association between Post and Category . I am trying to submit the Post form to create a post with the selected category from the dropdown <select> . Form is rendering correclty using: <div id="form-categories-widget"> <select id="shop_bundle_managementbundle_posttype_categories" name="shop_bundle_managementbundle_posttype[categories]"> {% for key,val in form.categories.vars.choices %} <option value="{{ val.value }}" {{ form.categories.vars.value == '' and key == 0 ? '

问题 I'm using Entity Framework 4 and my model relationships are automatically generated from the lookup table. My models consist of Request and Building . A request can have many buildings, and a building can be associated with many requests. I've found a few posts on how DropDownFor automatically selects an item based on model relationships. But the HtmlHelper CheckBoxFor wants an expression that returns bool. My models don't have a bool indicating checked because it is based on the relationship

问题 I have a few problems but I'm going to start with the first and smallest. I have two models with a many-many relationship, Category and Project. In each model I have an ICollection of the other model. I initialize the collection as a new HashSet() for the Project constructor and vice-versa for the Category. I've read online that this will create a new table in your database with the PK of each model as the PK in the new table. I custom named them and whatnot through Fluent API but you get the

问题 I have a many-to-many relationship with an additional column between two entities. On the owner side entity I have set the cascade type to persist. @OneToMany(cascade=CascadeType.PERSIST, fetch = FetchType.LAZY, mappedBy = "definitionType") private List<DefinitionProperty> definitionProperties = new ArrayList<DefinitionProperty>(); Here is my new entity which represents table: @EmbeddedId protected DefinitionPropertyPK pk; @JoinColumn(name = "dtid", referencedColumnName = "id", insertable =

问题 I have created these three tables that represent a many-to-many relationship between a doctor and a doctor's specialties. A doctor can have many specialties and many doctors can have a certain specialty. CREATE TABLE doctors ( doctor_id int(11) NOT NULL AUTO_INCREMENT, firstname varchar(30) NOT NULL, lastname varchar(30) NOT NULL, area varchar(50) NOT NULL, PRIMARY KEY (doctor_id) ); CREATE TABLE has_specialty ( doctor_id int(11) NOT NULL, specialty_id int(11) NOT NULL, PRIMARY KEY (doctor_id

问题 I have the models class User extends Model { protected $connection = 'mysql'; public function areas() { return $this->belongsToMany(Area::class, 'user_areas'); } } class Area extends Model { protected $connection = 'oracle'; } the user_areas table is searched on oracle, but this are on mysql. How I can indicate the connection for the pivot table? I found this partial solution and it has worked class User extends Model { protected $connection = 'mysql' public function areas() { $instance = new

问题 I have the following tables(only listing the required attributes) medicine (id, name), generic (id, name), med_gen (med_id references medicine(id),gen_id references generic(id), potency) Sample Data medicine (1, 'Crocin') (2, 'Stamlo') (3, 'NT Kuf') generic (1, 'Hexachlorodine') (2, 'Methyl Benzoate') med_gen (1, 1, '100mg') (1, 2, '50ml') (2, 1, '100mg') (2, 2, '60ml') (3, 1, '100mg') (3, 2, '50ml') I want all the medicines which are equivalent to a given medicine. Those medicines are

问题 I am using Fluent and NHibernate. I have two objects say A & B which has a many-to-many relationship between them. I am using a unidirectional many-to-many mapping when A HasMany B's. There is no reference in B about A (Unidirectional). This creates a third table (named ABMapping) in the Database which has the two columns relating to primary keys of A & B. If I delete the object A, the entries from the ABMapping table related to A are deleted. That's cool. But, now I am not able to delete an

问题 I'm working with ASP.NET MVC 4 and Entity Framework and I was searching for some way to make many to many relation and checkboxes from my db for a Create/Edit controller and view, I have found the answer with @Slauma answer for Create in MVC 4 - Many-to-Many relation and checkboxes but, I'd really like to see how this extends to Edit and Delete functionality as well like some other partners in this solution. Could someone please show how I would populate the ClassificationSelectViewModel in