Plugin uninstall: why run dbDelta after $wpdb->query($drop_sql)

The question:

i am reading professional wordpress. their code for uninstalling a plugin is

//build our query to delete our custom table
$sql = "DROP TABLE " . $table_name . ";";

//execute the query deleting the table
require_once(ABSPATH .’wp-admin/includes/upgrade.php’);

my question is why run dbDelta after $wpdb->query($sql);

The Solutions:

Below are the methods you can try. The first solution is probably the best. Try others if the first one doesn’t work. Senior developers aren’t just copying/pasting – they read the methods carefully & apply them wisely to each case.

Method 1

This is indeed bizarre. I think they first tried it with dbDelta, found it doesn’t work with DROP queries, and went with a straight $wpdb query instead. They then just forgot to take out the dbDelta stuff. It appears dbDelta collects creation queries in $cqueries and insert queries in $iqueries, but silently ignores the rest. What a lovely function…

To be sure, you could ask this question on the book forum, hopefully the authors hang around there. Don’t forget to mention you first asked it here, so we get some publicity!

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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