one-to-many

问题 Sorry if this question is too simple; I'm only entering 9th grade. I'm trying to learn about NoSQL database design. I want to design a Google Datastore model that minimizes the number of read/writes. Here is a toy example for a blog post and comments in a one-to-many relationship. Which is more efficient - storing all of the comments in a StructuredProperty or using a KeyProperty in the Comment model? Again, the objective is to minimize the number of read/writes to the datastore. You may make

问题 I have AssetGroup entity with has a one-to-many relation with Asset entity. There is a Entity base class which overrides Equals and GetHashCode . I am following the example of ch 20 parent child <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="TestNHibernate" namespace="TestNHibernate.Models" auto-import="true"> <class name="AssetGroup"> <id name="Id" column="Id" type="guid"> <generator class="guid"></generator> </id> <property name="Name

问题 Ok so this would be after changes that you guys helped me with , im assuming im getting a syntax error somewhere View @model OilNGasWeb.ModelData.Clients @{ ViewBag.Title = "Index"; } <h2>County's for </h2> <p> @Html.ActionLink("Create New", "Create",new { id = Model.ClientID },null) </p> <table> <tr> <th> @Html.DisplayNameFor(model => model.County) </th> <th> @Html.DisplayNameFor(model => model.Note) </th> <th> @Html.DisplayNameFor(model => model.Comment) </th> </tr> @foreach (var item in

问题 I want to update a one to many relationship. For example I have a model called Product class Product extends Model { protected $primaryKey = 'product_id'; public $timestamps = FALSE; public function Size(){ return $this->hasMany('App\Size'); } } and a model called Size class Size extends Model { public $timestamps = FALSE; protected $fillable = ['product_id','size']; public function Product(){ return $this->belongsTo('App\Product'); } here is my controller: public function update(Request

问题 I'm looking for possible ways to persist the following classes. Subsonic SimpleRepository looks like it might work, and people have said it should, when I asked a more general question. But I've been unable to find a single example of how to do this - or at least one I could understand. Can anyone point me to an example, or tell me how I could use Subsonic to map the following classes to a database? Note that I haven't designed the database - I'm hoping Subsonic will do that for me , lazy sod

问题 This question is based on the thread. If we have one-to-many data structure, we need to have a "help-table" to store for instance phonenumbers for one person. Many person cannot have the same phonenumbers. I look forward for an explanation why we then need two "help-tables" between many-to-many relations. An example of this is a question-site where many users can add the same tags: alt text http://files.getdropbox.com/u/175564/db/db-55.png Why do we need to have the tables Question-Tag-xref

问题 I have the following relationships within my doctrine entities: FavoriteRecipe /** * @ManyToOne(targetEntity="User", inversedBy="favoriteRecipes") */ private $user; /** * @ManyToOne(targetEntity="Recipe", inversedBy="favoriteRecipes") */ private $recipe; Recipe /** * @OneToMany(targetEntity="FavoriteRecipe", mappedBy="user") */ private $favoriteRecipes; User /** * @OneToMany(targetEntity="FavoriteRecipe", mappedBy="user") */ private $favoriteRecipes; In one of my controllers I have the

问题 It's my first question here on stack, so please be gentle :D I'm trying to create hibernate OneToMany relationship. When I try to fetch some data from my DB, I'm getting StackOverflowError. But when i remove OneToMany part, everything goes normally. This is part of my REST Service, for now it runs on VMware vFabric Server and MySQL DB. Fetch example: @Inject private EntityManager entityManager; ... entityManager.find(League.class, 1); ... entityManager.find(Team.class, 1); MySQL script:

问题 I have users, and users belong to a dealership. Upon user registration, I'm trying to save a new user, and a new dealership. User database has a dealership_id column, which I want to be populated with the ID of the newly created dealership. This is my current code in the UserController store method. public function store() { $user = new User(); $user->email = Input::get('email'); $user->password = Input::get('password'); $dealership = new Dealership(); $dealership->name = Input::get(

问题 I'm trying to do a one-to-many relationship in Entity Framework where one of the many items is optionally designated as default. public class SomeEntity { public int Id { get; set; } public Item DefaultItem { get; set; } // Optional public ICollection<Item> Items { get; set; } } public class Item { public int Id { get; set; } public string ItemName { get; set; } public SomeEntity SomeEntity { get; set; } } The configuration for the one-to-many in fluent API seems pretty straightforward: