The DELETE statement conflicted with the REFERENCE constraint "FK_BlogCommentReply_BlogCommentId" - sql

Question

I have a blog and keeping it simple for discussion, the main tables are Blog, BlogComment, BlogCommentReply and User.
A blog belongs to a User.
A comment belongs to a blog/user.
A comment reply belongs to a blog/comment/user.
I want to delete a User - UserId = 5.
My delete user stored procedure deletes (wrapped in a transaction) in this order:
BlogCommentReply
BlogComment
Blog (if the user is the author of the blog only)
User
It deletes the entry(s) in the BlogCommentReply for the User, then attempts to delete the entry(s) in the BlogComment for the User.
I then get the error:
The DELETE statement conflicted with the REFERENCE constraint "FK_BlogCommentReply_BlogCommentId".
The conflict occurred in database "DBGbngDev", table "dbo.BlogCommentReply", column
'BlogCommentId'.
It still thinks there is an entry in the BlogCommentReply table.
Here is the execute of the stored procedure with debug selects in it to show that it deletes the BlogCommentReply entry but then fails on the delete of the BlogComment.
Table definitions:
----------------------- BlogComment table (parent to blogCommentReply)
CREATE TABLE [dbo].[BlogComment](
[BlogCommentId] [int] IDENTITY(1,1) NOT NULL,
[UserId] [int] NOT NULL,
[BlogId] [int] NOT NULL,
[BlogCommentContent] [varchar](max) NOT NULL,
[LikeCount] [int] NOT NULL,
[DisLikeCount] [int] NOT NULL,
[DateTimeOfBlogComment] [datetime] NOT NULL,
CONSTRAINT [PK_BlogComment] PRIMARY KEY CLUSTERED
(
[BlogCommentId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
SET ANSI_PADDING OFF
GO
ALTER TABLE [dbo].[BlogComment] WITH CHECK ADD CONSTRAINT [FK_BlogComment_BlogId] FOREIGN
KEY([BlogId])
REFERENCES [dbo].[Blog] ([BlogId])
GO
ALTER TABLE [dbo].[BlogComment] CHECK CONSTRAINT [FK_BlogComment_BlogId]
GO
ALTER TABLE [dbo].[BlogComment] WITH CHECK ADD CONSTRAINT [FK_BlogComment_UserId] FOREIGN
KEY([UserId])
REFERENCES [dbo].[User] ([UserId])
GO
ALTER TABLE [dbo].[BlogComment] CHECK CONSTRAINT [FK_BlogComment_UserId]
GO
----------------------- BlogCommentReply table (child)
CREATE TABLE [dbo].[BlogCommentReply](
[BlogCommentReplyId] [int] IDENTITY(1,1) NOT NULL,
[UserId] [int] NOT NULL,
[BlogCommentId] [int] NOT NULL,
[BlogId] [int] NOT NULL,
[BlogCommentReplyContent] [varchar](max) NOT NULL,
[LikeCount] [int] NOT NULL,
[DisLikeCount] [int] NOT NULL,
[DateTimeOfBlogCommentReply] [datetime] NOT NULL,
CONSTRAINT [PK_BlogCommentReply] PRIMARY KEY CLUSTERED
(
[BlogCommentReplyId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
SET ANSI_PADDING OFF
GO
ALTER TABLE [dbo].[BlogCommentReply] WITH CHECK ADD CONSTRAINT [FK_BlogCommentReply_BlogCommentId]
FOREIGN KEY([BlogCommentId])
REFERENCES [dbo].[BlogComment] ([BlogCommentId])
GO
ALTER TABLE [dbo].[BlogCommentReply] CHECK CONSTRAINT [FK_BlogCommentReply_BlogCommentId]
GO
ALTER TABLE [dbo].[BlogCommentReply] WITH CHECK ADD CONSTRAINT [FK_BlogCommentReply_BlogId] FOREIGN
KEY([BlogId])
REFERENCES [dbo].[Blog] ([BlogId])
GO
ALTER TABLE [dbo].[BlogCommentReply] CHECK CONSTRAINT [FK_BlogCommentReply_BlogId]
GO
ALTER TABLE [dbo].[BlogCommentReply] WITH CHECK ADD CONSTRAINT [FK_BlogCommentReply_UserId] FOREIGN
KEY([UserId])
REFERENCES [dbo].[User] ([UserId])
GO
ALTER TABLE [dbo].[BlogCommentReply] CHECK CONSTRAINT [FK_BlogCommentReply_UserId]
GO
Extracted parts of the delete stored procedure (#a_UserId = 5):
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-- Step 6. Get the number of blog comments replys for the user.
-- Note: there may not be any.
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
SELECT #BlogCommentReplysCount = Count(*)
FROM dbo.BlogCommentReply
WHERE ( UserId = #a_UserId )
SELECT #ReturnCode = ##ERROR
IF #ReturnCode <> 0
BEGIN
ROLLBACK TRANSACTION
SELECT #Message = 'Critical Error - procedure DeleteBlog failed during the select of BlogCommentReply. User id: ' + CAST(#a_UserId AS VARCHAR) + '. '
RAISERROR (#Message, 16, 1)
END
SELECT '#BlogCommentReplysCount: ' + CAST(#BlogCommentReplysCount AS VARCHAR) + '. '
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-- Step 7. Delete the BlogCommentReply entries for the user.
-- Note: the user may not have made any.
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
DELETE dbo.BlogCommentReply
WHERE ( UserId = #a_UserId )
SELECT #ReturnCode = ##ERROR,
#RowCount = ##ROWCOUNT
IF #ReturnCode <> 0 AND #RowCount > 0
BEGIN
ROLLBACK TRANSACTION
SELECT #Message = 'Critical Error - procedure DeleteBlog failed during the delete of BlogCommentReply. User id: ' + CAST(#a_UserId AS VARCHAR) + '. '
RAISERROR (#Message, 16, 1)
END
SELECT 'Deleted BlogCommentReply'
SELECT '#ReturnCode: ' + CAST(#ReturnCode AS VARCHAR) + '. '
SELECT '#RowCount: ' + CAST(#RowCount AS VARCHAR) + '. '
SELECT '#a_UserId: ' + CAST(#a_UserId AS VARCHAR) + '. '
SELECT Count(*) as AFTERDELETE
FROM dbo.BlogCommentReply
WHERE ( UserId = #a_UserId )
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-- Step 8. Get the number of blog comments for this user.
-- Note: there may not be any.
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
SELECT #BlogCommentsCount = Count(*)
FROM dbo.BlogComment
WHERE ( UserId = #a_UserId )
SELECT #ReturnCode = ##ERROR
IF #ReturnCode <> 0
BEGIN
ROLLBACK TRANSACTION
SELECT #Message = 'Critical Error - procedure DeleteBlog failed during the select of BlogComment. User id: ' + CAST(#a_UserId AS VARCHAR) + '. '
RAISERROR (#Message, 16, 1)
END
SELECT '#BlogCommentsCount: ' + CAST(#BlogCommentsCount AS VARCHAR) + '. '
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-- Step 9. Delete the BlogComment entries for the user.
-- Note: the user may not have made any.
--+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
SELECT Count(*) as BEFORE
FROM dbo.BlogComment
WHERE ( UserId = #a_UserId )
SELECT 'Going to delete BlogComment'
DELETE dbo.BlogComment
WHERE ( UserId = #a_UserId )
SELECT #ReturnCode = ##ERROR,
#RowCount = ##ROWCOUNT
IF #ReturnCode <> 0 AND #RowCount > 0
BEGIN
ROLLBACK TRANSACTION
SELECT #Message = 'Critical Error - procedure DeleteBlog failed during the delete of BlogComment. User id: ' + CAST(#a_UserId AS VARCHAR) + '. '
RAISERROR (#Message, 16, 1)
END
SELECT 'Deleted BlogComment'

Answer 1

I think it's better to have your complete stored procedure script to check the error, but for the mean time I guess the problem is here:
DELETE dbo.BlogCommentReply
WHERE ( UserId = #a_UserId )
Ok, it's deleting all of comment replies which the related user (i.e. #a_UserId = 5) has.
But look at the rest of your script:
DELETE dbo.BlogComment
WHERE ( UserId = #a_UserId )
It's deleting all of user's comments, WHILE they may have some other comment replies for another users and they are not deleted. So I think the problem is here.
Maybe it's better to change the first deletion part to:
DELETE dbo.BlogCommentReply
WHERE ( UserId = #a_UserId )
DELETE dbo.BlogCommentReply
FROM [dbo].[BlogComment]
WHERE dbo.BlogCommentReply.BlogCommentId=[dbo].[BlogComment].BlogCommentId
AND [dbo].[BlogComment].UserId=#a_UserId

Answer 2

It's very simple you are deleting comment's reply of a specific user while other users might have reply under the same comment.
I you really want to delete all related info of a user , you have to go with different approach like finding all replies under that user's comment and delete those.