[英]inserting data into tables with foreign keys
I have 2 tables in ms sql server 2008 R2, one of which has foreign key relation to the other 我在ms sql server 2008 R2中有2个表,其中一个表与另一个表有外键关系
pretty simple: 很简单:
tableA
prefix nchar(10)
value nchar(50)
tableB
prefix nchar(10)
value nchar(50)
ALTER TABLE [dbo].[tableB]
WITH CHECK ADD CONSTRAINT [FK_TableA_TableB] FOREIGN KEY([prefix])
REFERENCES [dbo].[TableA] ([prefix])
I fill in data in the tables using the management studio edit table. 我使用管理工作室编辑表填写表格中的数据。 ensuring each prefix in
tableB
has a matching prefix in tableA
. 确保每个前缀
tableB
有一个前缀匹配tableA
。
Then I import the tables into visual studio C# to create an entity framework model. 然后我将表导入visual studio C#以创建实体框架模型。 Everything seem to work fine until I start to reference data in
tableA
from tableB
using the navigation handle, it comes up empty handed. 一切似乎工作正常,直到我开始使用导航句柄从
tableB
引用tableA
数据,它空出来了。
ie tableB.tableA
s come out as null. 即
tableB.tableA
s为null。
Is there a step that needs to be done to update foreign key relations in entity framework and/or ms sql server? 是否需要在实体框架和/或ms sql server中更新外键关系?
To help others with a similar problem, I am posting what I believe is the solution. 为了帮助其他类似问题,我发布了我认为的解决方案。 Turns out I assumed references were loaded automatically in the Entity Framework.
事实证明我假设引用是在Entity Framework中自动加载的。 In order to get updated, references need to be explicitly loaded like this
为了获得更新,需要像这样显式加载引用
if (!tableB.tableAs.IsLoaded)
tableB.tableAs.Load();
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