data-modeling

问题 I know the general rule that we should test a trained classifier only on the testing set. But now comes the question: When I have an already trained and tested classifier ready, can I apply it to the same dataset that was the base of the training and testing set? Or do I have to apply it to a new predicting set that is different from the training+testing set? And what if I predict a label column of a time series (edited later: I do not mean to create a classical time series analysis here, but

问题 I know the general rule that we should test a trained classifier only on the testing set. But now comes the question: When I have an already trained and tested classifier ready, can I apply it to the same dataset that was the base of the training and testing set? Or do I have to apply it to a new predicting set that is different from the training+testing set? And what if I predict a label column of a time series (edited later: I do not mean to create a classical time series analysis here, but

问题 I've been experimenting with MongoDB in order to move some parts of an app to it. I'm thinking a document-based db like mongodb would be a nice fit for tournament brackets but I'm having sort of a hard time coming up with a suitable model. (still trying to break free from RDBMS dogma) Anyone have any ideas for a good way to model Single AND Double-elimination tournament brackets? 回答1: Both tournament variation basically come down to each match either resulting in one of these options : Player

问题 Context: I am creating a kind-of-wiki page in Angular. The wiki page would probably not get bigger than 5000 articles in total. I want to get the most efficient (pageload) way possible but I think I am too new to this to oversee the consequences of one option over the other. Of course I also would like to follow conventions. Problem: I have a collection of articles in firestore which I want to categorize. An article should belong to one category. A category can belong to one category (as a

问题 Context: I am creating a kind-of-wiki page in Angular. The wiki page would probably not get bigger than 5000 articles in total. I want to get the most efficient (pageload) way possible but I think I am too new to this to oversee the consequences of one option over the other. Of course I also would like to follow conventions. Problem: I have a collection of articles in firestore which I want to categorize. An article should belong to one category. A category can belong to one category (as a

问题 Can a single column in a table can be referenced to multiple tables? 回答1: A very late answer, but for whoever is wondering & googeling. YES this can be done, but it is NOT good practice and even though it is quite simple, it will probably blow up in your face if you're not very aware of what you are doing. Not recommended. However, I can see uses. For instance, you have a large table of millions of records, and you want in exceptional cases link to unknown or multiple tables (in which case it

问题 Currently, I'm looking for best practice to "applying discounts" to cart/order. So, I'm planning to implement such kind of discounts as... fixed user's discount (for example, I'd like to give 10% discount to my favourite customer) discount for number of items (for example, you're buying 10 different colored pens and you'll be getting discount of 1.5%) discount for coupon (for example, during promo action we've produced 100 coupons with 10% discount each. Coupons work only for one order and

问题 Currently, I'm looking for best practice to "applying discounts" to cart/order. So, I'm planning to implement such kind of discounts as... fixed user's discount (for example, I'd like to give 10% discount to my favourite customer) discount for number of items (for example, you're buying 10 different colored pens and you'll be getting discount of 1.5%) discount for coupon (for example, during promo action we've produced 100 coupons with 10% discount each. Coupons work only for one order and

问题 I'm attempting to create an object of an HL7 message by parsing a raw text string. The object model is a follows. The object I want to create would be a representation of this, allowing calling methods to access information based on indexes. If information from the 2nd sub-subfield in the 3rd subfield of the 5th field of the segment named "PID" for the message you'd do it like this: HL7Message h = HL7Message(messageRawText); Console.Writeline(h.GetInfo("PID",5,3,2)+" is sub-subfield I'm

问题 I'm attempting to create an object of an HL7 message by parsing a raw text string. The object model is a follows. The object I want to create would be a representation of this, allowing calling methods to access information based on indexes. If information from the 2nd sub-subfield in the 3rd subfield of the 5th field of the segment named "PID" for the message you'd do it like this: HL7Message h = HL7Message(messageRawText); Console.Writeline(h.GetInfo("PID",5,3,2)+" is sub-subfield I'm