Needle cards are index cards with text, written by hand or typewriter, that have a line of prepunched holes along one or more sides. By cutting or punching away (notching out) the paper between a hole and the edge of the card, the card is associated with a category. By putting long (knitting) needles through certain holes in a deck of such cards, lifting and shaking gently, cards that belong to a combination of categories can be selected. This tool is less useful for data sets larger than 10,000 records.[1]
Affectionately referred to as "The Knitting Needle Computer", these database-like systems were popular sometime in the 1960s and 1970s. Science teachers may still use these as a teaching tool for relational databases. Indexed card systems can be made with index cards and a hole punch.