实体框架生成错误的SQL

Question

I am attempting to insert a record through Entity Framework and it appears the SQL generated is incorrect. I am inserting into the 'PostingSelections' table. This table has FK's to three other tables 'PropertyPosting', 'PropertySummary' and 'User'. The FK to User is nullable. This is using a MySQL database, which I am suspicious is the problem.

The DDL for the PostingSelections table is:

CREATE TABLE `PostingSelections`(
    `Id` int NOT NULL AUTO_INCREMENT UNIQUE, 
    `SelectionType` TINYINT UNSIGNED NOT NULL, 
    `Date` datetime NOT NULL, 
    `SourceIPAddress` longtext NOT NULL, 
    `PropertyPosting_Id` int NOT NULL, 
    `PropertySummary_Id` int NOT NULL, 
    `User_Id` int);

My code is:

var postingselection = new postingselection();
postingselection.PropertyPosting_Id = 24;
postingselection.PropertySummary_Id = 24;  
postingselection.SelectionType = 1;  
postingselection.Date = DateTime.UtcNow;  
postingselection.SourceIPAddress = "TBD";   

db.postingselections.Add(postingselection);
db.SaveChanges();

The code is exactly the same as what is automatically generated by entityframework when I generate the controller automatically. The SQL that EF is generating is:

INSERT INTO `postingselections`(
`SelectionType`, 
`Date`, 
`SourceIPAddress`, 
`PropertyPosting_Id`, 
`PropertySummary_Id`, 
`User_Id`, 
`propertyposting_Id`, 
`propertysummary_Id`, 
`user_Id`) VALUES (
1, 
4/18/2017, 
TBD, 
24, 
24, 
0, 
24, 
24, 
NULL);
SELECT
`Id`
FROM `postingselections`
 WHERE  row_count() > 0 AND `Id`=last_insert_id()

See how it has generated three columns twice? PropertyPosting_Id, PropertyPosting_Id and User_Id? The error that is generated as expected is:

Failed in 71 ms with error: Column 'User_Id' specified twice

Could someone please help? This is a very basic insert, and I can't find any other similar postings. I can only conclude I have found a bug in EF for mySQL and will have to do this instead with a manual SQL statement.

Answer 1

I encountered a similar problem few days ago, I think it's related to the the Primary Key of "PostingSelections" table.

Try to specify a PK for your table, otherwise EF wont differentiate the records.