In addition, like most things, the cards got more complicated as time went on. Of course, the cards are not going to stay sorted that way. If you want to logically invert, you just use the stack in your hand instead of the cards on your desk. If you repeat the operations on the cards that stayed on the needle you are doing an or operation. You could also use multiple needles, but that gets hard to handle eventually. Miller” notch, you’ve done a logical and operation. If you pick up the cards from your desk and repeat the operation with the “female” notch and the “Mrs. Of course, the best queries have multiple parts. Any that have the hole open will fall down on your desk. When you lift the needle, all the ones that have an intact hole in that spot will stay on the needle. You can take the stack in any order and put a long needle - like a knitting needle - through, say, the 4th-grade hole. Separating notched cards from those that are not. You might as well just look for text on the card. Looking for punched holes isn’t really all that useful, though. Miller’s 4th-grade class, you’d open up the female, 4th grade, and Mrs. Another might say “male” next to one that said “female.” Whoever produced the card would use some tool to open up the holes that applied to that card. If your report card was on an edge-punch card there would be holes all around it with little labels.
Let’s go back to our report card example.
There were several well-known brand names including Cope-Chat, E-Z Sort, Flexisort, and McBee Keysort cards. We’ve also heard them called “needle cards” for reasons that will soon become apparent. They were often called edge-punched cards or edge-notched cards. These cards had holes punched around the edges. Not the punched cards we know from vintage computers. The answer was in a type of punched card. Imagine if you had a really complex data set.
#Perforated edge file cards manual
Sure, you could come up with some scheme, like the class and teacher folders had lists of names, but that’s a hack and not in a good way.īesides, what happens if someone wants the report cards for all girls in the 8th, 9th, and 10th grades? That’s a lot of manual selecting. In a filing cabinet, I’d need three copies of the report card - in a day when copies were hard to produce. With a database table, that’s easy to just create a view based on a query for any of those items. If they were in a filing cabinet, you’d probably want the folders to have student’s names. The problem with those is that you have a single primary key or you have a lot of duplication. Not that people didn’t have filing cabinets. How Do You Sort Massive Amounts of Paper Records? But there was actually a better system that had fairly wide use.
#Perforated edge file cards how to
But what did database management look like in, say, 1925? You might think it was nothing but a filing cabinet and someone who knew how to find things in it.
For example, only a few of us remember how to use slide rules, but they helped send people to the moon. Sometimes they just used brute force but sometimes they used little tricks that we’ve almost forgotten. Yet somehow people computed tables, kept ledgers, and even wrote books without any help from computers at all. Modern computers have been around an even shorter period. It is hard to remember that practical computers haven’t been around for even a century, yet.
0 kommentar(er)
