Yes, they are pointers. But the indexed fields have to be duplicated for efficient reading. From Wikipedia: "An index is a copy of select columns of data from

Yes, they are pointers. But the indexed fields have to be duplicated for efficient reading. From Wikipedia: "An index is a copy of select columns of data from a table that can be searched very efficiently that also includes a low-level disk block address or direct link to the complete row of data it was copied from." [1] When you reference a field in an index, you're effectively duplicating this column on disk. We can discuss semantics, but at the end of the day, indexes are glorified copies of your columns in a specific order. [1] https://en.wikipedia.org/wiki/Database_index https://en.wikipedia.org/wiki/Database_index