Linq to Sql外键关系 [英] Linq to Sql Foreign key relationships

问题描述

表名：作者

• AuthorID - >主键


• 名字


• 姓氏





表名：<$ c
$ b



• ISBN - >主键


• BookTitle
  
  $ b

  表格名称：
  

• 版本号


• CopyRight
AuthorISBN





• ISBN - >外键
  
• AuthorID - >外键






下面的代码块怎么没有触发intellisense，因为Linq-to-SQL自动创建基于外键关系的属性？在我的情况下，它不... ...



错误：






title.AuthorISBN





这个名称不存在于当前的上下文中，不是让我添加一张照片，而是Author与AuthorISBN的一对多关系，标题也与AuthorISBN具有一对多关系




代码：



  BooksDataContext数据库= new BooksDataContext（）; 
 var authorsAndTitles = 
 from title in database.Titles 
 from book in title.AuthorISBN 
 let author = book.Author 
 orderby author.LastName，aurthor.FirstName， title.BookTitle 
选择新的{author.FirstName，author.LastName，title.BookTitle}; 
  




解决方案

好像你犯了一个错字：

  var authorsAndTitles = 
 from database in database.Titles 
 from book in ** tilte **。AuthorISBN 
 let author = book.Author 
 orderby author.LastName，aurthor.FirstName，title.BookTitle 
 select new {author.FirstName，author.LastName，title.BookTitle}; 
  

不应该是title.AuthorISBN insteand tilte.AuthorISBN？我用**包围了这个词。





除此之外，我会试试这个：



  var authorsAndTitles = 
 from database in database.Titles 
 let author = title.AuthorISBN.Author 
 orderby author.LastName，aurthor.FirstName，title.BookTitle 
选择新的{author.FirstName，author.LastName，title.BookTitle}; 
  

新尝试：



  var authorsAndTitles = 
 from autISBN in database.AuthorISBN 
 let author = autISBN.Author 
 let title = autISBN.Titles 
 orderby author.LastName，author。 FirstName，title.BookTitle 
 select new {author.FirstName，author.LastName，title.BookTitle}; 
  




Table name: Author

• AuthorID -> primary key
• FirstName
• LastName

Table name: Titles

• ISBN -> primary key
• BookTitle
• EditionNumber
• CopyRight

Table name: AuthorISBN

• ISBN -> foreign key
• AuthorID -> foreign key

How come the below code block below does not trigger the intellisense, since Linq-to-SQL automatically creates properties based on foreign-key relationship? In my case it doesn't...

ERROR:

The name title does not exist in current context in title.AuthorISBN

It's not letting me add a photo, but 'Author' has 'one-to-many' relationship with AuthorISBN, and 'Titles' also has 'one-to-many' relationship with AuthorISBN

Code:

 BooksDataContext database = new BooksDataContext();
 var authorsAndTitles =
          from title in database.Titles
          from book in title.AuthorISBN
          let author = book.Author
          orderby author.LastName, aurthor.FirstName, title.BookTitle
          select new { author.FirstName, author.LastName, title.BookTitle };

解决方案

It seems like you made a typo:

 var authorsAndTitles =
          from title in database.Titles
          from book in **tilte**.AuthorISBN
          let author = book.Author
          orderby author.LastName, aurthor.FirstName, title.BookTitle
          select new { author.FirstName, author.LastName, title.BookTitle };

Shouldn't it be title.AuthorISBN insteand of tilte.AuthorISBN? I surrounded the word with **.

Besides that, I would try this:

var authorsAndTitles =
          from title in database.Titles
          let author = title.AuthorISBN.Author
          orderby author.LastName, aurthor.FirstName, title.BookTitle
          select new { author.FirstName, author.LastName, title.BookTitle };

New attempt:

var authorsAndTitles =
          from autISBN in database.AuthorISBN
          let author = autISBN.Author
          let title = autISBN.Titles
          orderby author.LastName, author.FirstName, title.BookTitle
          select new { author.FirstName, author.LastName, title.BookTitle };

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