entity-relationship

问题 This is a follow up question from here: linq issue with creating relationships in regards to the answer I recieved. Im not sure what has happend but I get an error: The underlying connection was closed: An unexpected error occurred on a receive. And this is where the exception happens: string uriGroup = "http://localhost:8000/Service/Group"; private void ListGroups_Click(object sender, RoutedEventArgs e) { XDocument xDoc = XDocument.Load(uriGroup); // this line var groups = xDoc.Descendants(

问题 Can you tell me how I can generate an ER diagram for my database1 (see below) created with VS 2015 Thanks in advance 回答1: DB Objects in the editor will be related as in Diagram so Just relate objects in the Db and drag to editor. 回答2: Ensure you installed either Microsoft SQL Server Data Tools or Microsoft Web Developer Tools in order to get the Entity Data Model Designer. These are the steps to generate entity relationship diagram. It was tested in VS2012 Open Visual Studio Create a project

问题 data (table name) dataid PK, value1, value2, value3 data_address (table name) dataaddressid PK, dataid - id to errenddataid, addressid1 - id to en addressid, addressid2 - id to en addressid, type address (table namne) addressid PK - id to addressid1 or addressid2, address1, address2, name, zipcode, city I have a really hard time trying to map this relations using Entity Framework 5, if some one have an idea or good links I would much appreciate that! 回答1: If you are certain that the database

问题 data (table name) dataid PK, value1, value2, value3 data_address (table name) dataaddressid PK, dataid - id to errenddataid, addressid1 - id to en addressid, addressid2 - id to en addressid, type address (table namne) addressid PK - id to addressid1 or addressid2, address1, address2, name, zipcode, city I have a really hard time trying to map this relations using Entity Framework 5, if some one have an idea or good links I would much appreciate that! 回答1: If you are certain that the database

问题 I'm using Entity Framework and MVC3, and my problem is that I can't scaffold Controllers if the class inherits from another Class. Example: This is Base Class using System; using System.Collections.Generic; namespace CRMEntities { public partial class Company { public int Id { get; set; } } } This is Lead Class (Child) using System; using System.Collections.Generic; namespace CRMEntities { public partial class Lead : Company { public Lead() { this.Status = 1; this.IsQualified = false; }

问题 Tracking a familial relationship in Core Data (1 parent entity + 2 types of children, one of which is recursive), trying to create a drop-menu in Interface Builder that lists the names of the parent entities so that the user can choose one to associate as the parent of the entry being edited. I've got the bindings all set, but when it runs it produces the following error text in the first slot of the menu: Relationship fault for ( <NSRelationshipDescription: 0x100143ed0> ), name parent,

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: MetaSearch “undefined method `model_name' for NilClass:Class” for global bar search This is the error I'm getting using my updated code when I try going to a user's profile or a individual posts (/posts/1). Its weird that its trying to access the unlike partial anyway because its a new user without any likes. I've got the code exactly as it shows in the tutorial I used to do this with following users. It works

问题 Seems I have a slight problem with my linq, I have a datacontract for Groups and I have a seperate datacontract for messages. Messages can be part of a Group. However when I update a message record its not reflected when I list the group information, the message is still the same for that group. But yet the update is reflected when I directly list messages? This is how I add a message to a group: //lists for reference: List<Group> Groups = new List<Group>(); List<Message> messages = new List

问题 When going through a learning article about related entity loading in Entity Framework MSDN, I came across the following: It is also possible to eagerly load multiple levels of related entities . The queries below show examples of how to do this for both collection and reference navigation properties. ...[Examples demonstrating the above]... Note that it is not currently possible to filter which related entities are loaded . Include will always being in all related entities. This seems

问题 When going through a learning article about related entity loading in Entity Framework MSDN, I came across the following: It is also possible to eagerly load multiple levels of related entities . The queries below show examples of how to do this for both collection and reference navigation properties. ...[Examples demonstrating the above]... Note that it is not currently possible to filter which related entities are loaded . Include will always being in all related entities. This seems