CODEWITHSUNDEEP
phpmysqloptimization
Imperialized
Imperialized

Reputation: 443

Deleting entire family of a comment thread

Ok, so here is my problem. I am implementing a forum for a client of mine. The code was written years ago and I am working on a delete feature.

Basically, you have your Primary topic. People can comment on that, and comment then on the comments.

The layout would be as such:

[ Main Post ]
  [Comment A - ID 1 - Family Founder]
    [Comment 2 - Parent 1 - ID 2]
    [Comment 3 - Parent 1 - ID 3]
      [Comment 4 - Parent 3 - ID 4]
  [COmment B - ID 5 - Family Founder]
    [Comment 6 - Parent 5 - ID 6]
      [Comment 7 - Parent 6 - ID 7]

The table stores this info as follows: ID | Parent ID | Topic ID | Comment Content

Currently, it is setup to run with two functions The first, calls the primary comment (Comment ID 1) and then at the bottom, it calls to see if there are any children of comment ID 1 then loops through them, etc. It is confusing to try to explain.

The problem is, I am unable to keep track of the initial family found (A and B, IDs 1 and 5 respectively).

The only way I can think to do this is to call a function making a multitude of queries on the database until the children count is 0. Storing all the IDs then running a delete query.

Any help is appreciated. If I can explain it better please let me know.

Upvotes: 0

Views: 45

Answers (2)

Sebastiaan Mannem
Sebastiaan Mannem

Reputation: 505

I think you should use reoccurrence, e.a. a function that first prints the parrent and then searches all its children and runs himselve for the children. This would mean that you have the following function calls:

  • ShowPost(Main) calling ShowPost 1
    • Showpost 1
    • calling showpost 2, which prints and ends
    • calling showpost 3
      • Showpost 3 calling ShowPost 4, which ends
    • and the showpost 3 ends as well.
    • Then ShowPost(1) ends resulting in
  • ShowPost(Main) calling ShowPost 5
    • ShowPost 5 calling ShowPost 6 etc.

Basically something like:

function showPost(int ID) {
  #Find record
  mysql.runquery ...
  #print record
  echo '...';
  #find children
  myql.runquery ...
  while (c=mysql.nextrecord()) {
    showpost (c.ID);
  }
}

For deletion something like:

function deletePost(int ID) {
  #find children
  myql.runquery ...
  while (c=mysql.nextrecord()) {
    deletepost (c.ID);
  }
  #Then delete himselve.
  mysql.run_sql ('delete from table where id = '.ID);
}

Upvotes: 0

Mike Summers
Mike Summers

Reputation: 2239

ParentID is effectively a foreign key so I'd add a 

FOREIGN KEY(ParentID) REFERENCES Comment(id) ON DELETE CASCADE

constraint

Upvotes: 1

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