In response to Xirre
You tend to get some awesomely bad cases of spaghetti schema when you start adding two columns to help achieve one output value.
In response to Stephen001
Stephen001 wrote:
You tend to get some awesomely bad cases of spaghetti schema when you start adding two columns to help achieve one output value.

At least it's awesome.
In response to King_ed
King_ed wrote:
They already have the feature which when u read something it marks it as read therefore it is easy to implement it.

Not quite. The post-read records have a limited lifespan, lest the database choke on them. This system could not be adapted to count unique views without removing said lifespan, or at best keeping a running count that only increments when a new record is created. A column for the count would still have to be added to the post table, or else an additional table would need to be created (not ideal) that links to it.
How about this theory: 2 programs on 1 page. So, say you were just going to make a page that took view counts. Once you've created that page, apply it to every forum page. It creates a row with an id similar to the post ID. So you'll have a new table, won't have to mess with the forum's columns or rows, and it's basically its own individual program that can run by itself, provided that it has the post ID.
Because then to return the page seen here, you'd need to join two tables across a bunch of IDs, which impacts database and consequently site performance.
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