Why would an unique index get moved to the primary key after the underlying column is dropped?
So I had a table with a primary key and a bunch of different columns. Columns A, B, and C were all unsigned ints (like the primary key column) and each column had a unique constraint
I dropped the A, B, and C columns, and then I got a warning that there were now duplicate unique constraints. When I checked the table structure I saw that unique indexes had been moved to the primary key column.
My assumption was that dropping a column would also drop its index, why would the index be moved to the primary key?