mysql - DB Schema for an application -


i've application, need post comments on blog paragraphs, not comment on blogs. paragraphs separated 2 new-line characters.

i'll splitting post received using post.split('\n\n'), saving post , paragraphs in separate tables (blog , paragraphs). whenever new comment received, i'll saving in comments table para_id received.

following db schema i'm planning build.

table blog

-id -title -date

table paragraphs

-id -para -sequence_no -blog_id(fk)

table comments 

-id -comment -para_id(fk) -date

the above design has flaw. consider example when post updated, ie, either new paragraph inserted between 2 paragraphs, or paragraph removed. result in distortion of sequence(ordinal number). how handle such use-case?

calculate unique hash value each paragraph , use combination of postid+paragraphhash primary key.

store timestamp along each paragraph. every time user edits post, update timestamp existing paragraphs. easy spot deleted paragraphs.


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