实体框架不级联删除

Question

In short EF default is to delete cascade. I have a parent/child relationship I set up using Entity Developer by Devart. It is set to delete cascade. The parent table looks like this:

CREATE TABLE `Tools` (
`ToolNumber`    TEXT,
`ToolID`    INTEGER PRIMARY KEY AUTOINCREMENT
);

The child table has the following definition:

CREATE TABLE `FirstParts` (
`FirstPartID`   INTEGER PRIMARY KEY AUTOINCREMENT,
`DateTime`  TEXT,
`ToolID`    INT32 NOT NULL,
CONSTRAINT `FK_FirstParts_Tools` FOREIGN KEY(`ToolID`) REFERENCES 
`Tools`(`ToolID`) ON DELETE CASCADE
);

I can add records to the parent/child by using the following code. When I use this I DO get a record in each table and the ToolID is set correctly.

using (var context = new Entities())
{
    var query = from t in context.Tools
                        where t.ToolNumber == "Hello"
                        select t;

    if (!query.Any())
    {
          var tool = new Tool()
                     {
                        ToolNumber = "Hello",
                        FirstParts = new System.Data.Entity.Core.Objects.DataClasses.EntityCollection<FirstPart>() { new FirstPart() { DateTime = "Same text" } }
                   };

        context.AddToTools(tool);
        context.SaveChanges();
    }
}

When I use the following to delete the parent the child is left hanging:

 using (var context = new Entities())
 {
     var query = (from t in context.Tools
                         select t).FirstOrDefault();

     if (query != null)
     {
        context.Tools.DeleteObject(query);
        context.SaveChanges();
     }
}

If I use SQLite Browser and do the following SQL then both parent and child gets deleted properly So I know it is not SQLite.

DELETE FROM Tools WHERE Tools.ToolID = 6;

I have looked for the following to make sure Cascade delete is not getting overridden:

OnModelCreating(false)

It is not present in the code created by Entity Developer.

What could be causing EF to not cascade delete?

Answer 1

Please add "Foreign Key Constraints=On;" to your connection string to fix the issue. Refer to https://www.devart.com/dotconnect/sqlite/docs/?Devart.Data.SQLite~Devart.Data.SQLite.SQLiteConnection~ConnectionString.html .