INSERT 语句与实体框架核心中的 FOREIGN KEY 约束冲突，单个语句中有 2 个表

Question

I have following 2 classes.

public partial class Query
{
    public int Id { get; set; }
    public virtual QueryGroup QueryGroup { get; set; }
}


public partial class QueryGroup
{
    public int Id { get; set; }
    public virtual ICollection<Query> Query { get; set; }
}

Now these 2 classes are parsed from json. so both Ids are 0, because it is adding (not updating).

When I do below.

projectContext.SaveChanges();

It gives below error, how to add them both in single statement. or will it require seperate add?

SqlException: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Query_QueryGroup". The conflict occurred in database "Project", table "dbo.QueryGroup", column 'Id'.

Answer 1

As per the conflict mentioned by you, below is my opinion:

If you have a table A having a foreign-key to table B , then while adding a record to table A the foreign-key value must exist in the table B . If the foreign-key value does not exist in table B then the above mentioned SqlException occurs.

Hence you need to add data to table B first and then table A . You can create a single sql transaction for this.

Answer 2

如果您尝试将数据插入Query ，则表QueryGroup 中必须有带有 ForeignKey 的数据，以便您可以将数据添加到两个表，然后SaveChanges