** UnhandledExceptionEventHandler :: OFFICIAL LC / CHATTER THREAD **
02-18-2016
, 01:24 AM
02-18-2016
, 01:26 AM
Btw, i had to sum up 7 int fields individually in a list of objects.
Ie List( Obj(a1,b1,c1), Obj2(a2,b2,c2) ) summing up all as, all bs, all cs, etc
Finally had a real world scenario to try out fold left!
Warning, may be gross:
I think its beautiful
Ie List( Obj(a1,b1,c1), Obj2(a2,b2,c2) ) summing up all as, all bs, all cs, etc
Finally had a real world scenario to try out fold left!
Warning, may be gross:
Code:
// all 7 start values in a tuple at 0
val start =(0, 0, 0, 0, 0, 0, 0)
objList.foldLeft(start)((total,entry) => {
(total._1 + entry.a,
total._2 + entry.b,
total._3 + entry.c,
total._4 + entry.d,
total._5 + entry.e,
total._6 + entry.f,
total._7 + entry.g)
})
I think its beautiful
02-18-2016
, 01:36 AM
02-18-2016
, 01:49 AM
Quote:
I think we're talking past in each other. Sorry about that, but this stuff is so abstract it's to be expected. Maybe an example will help. If you need a rule that says customers who have spent a lifetime total of $1000, not including any discounts (your VIPs), get a special discount that entitles them to 50% off any purchase on their birthday, but not to exceed $50 in total discount, that rule shouldn't live in your database. Even though, at the end of the day, that *is* about data integrity: it's just expressing a bunch of relations between numbers in the users table, the user_details table, and the orders table (or some such). RDBs, even sophisticated ones, do not have the expressive power needed to model complex business applications naturally.
EDIT: perhaps even more importantly, such rules are subject to very different rates of change than, say, rules about the allowed length of a first name. so you don't want them encoded in the database, otherwise when you change them you will break the integrity of existing data.
EDIT: perhaps even more importantly, such rules are subject to very different rates of change than, say, rules about the allowed length of a first name. so you don't want them encoded in the database, otherwise when you change them you will break the integrity of existing data.
Of course, that doesn't mean you can't use windowing in your example, but that, IMO, has nothing to do with the data and doesn't have anything do with what I was trying to say. I don't think of the query language and the data as the same thing. I also don't think that code should be confused with the queries. All unix philosophy, I guess.
02-18-2016
, 01:56 AM
Quote:
I didn't think anyone seriously did this level of complex calculations with a database or stored the results in a database... outside of highly specific and time-sensitive items, but even that's not a very good idea. It's a totally different digression. Anyone who defaults to this isn't thinking at all about how the database system works, and I'd have a long string of very difficult questions for anyone who suggests this unless his name is Erwin. Thought you thunk higher of me than this.
Of course, that doesn't mean you can't use windowing in your example, but that, IMO, has nothing to do with the data and doesn't have anything do with what I was trying to say. I don't think of the query language and the data as the same thing. I also don't think that code should be confused with the queries. All unix philosophy, I guess.
Of course, that doesn't mean you can't use windowing in your example, but that, IMO, has nothing to do with the data and doesn't have anything do with what I was trying to say. I don't think of the query language and the data as the same thing. I also don't think that code should be confused with the queries. All unix philosophy, I guess.
i was defending my point that business rules often belong in ruby/python/similar code, and not in the db, which it seemed you had taken issue with. i was also clarifying the term "business rules" which gets thrown around a lot, and which people often have different interpretations of, by providing a concrete example of one.
02-18-2016
, 02:08 AM
02-18-2016
, 02:33 AM
02-18-2016
, 05:47 PM
02-19-2016
, 05:49 AM
[IMG]
[/IMG]
Hi friends!,
I'm supposed to implement the above algorithm to produce a pseudo random bit stream, but I'm slightly confused about the first part.
i'm guessing i can use the xth bit of the clock to get a "random bit" in order to generate my seed?
but how do u "randomly" select 2 primes s.t. pq=3 mod4?, don't u have to already have a list of primes? or is it more a case of compute a list of number in the form 4x+3? and check if they can be written as pq?
[/IMG]Hi friends!,
I'm supposed to implement the above algorithm to produce a pseudo random bit stream, but I'm slightly confused about the first part.
i'm guessing i can use the xth bit of the clock to get a "random bit" in order to generate my seed?
but how do u "randomly" select 2 primes s.t. pq=3 mod4?, don't u have to already have a list of primes? or is it more a case of compute a list of number in the form 4x+3? and check if they can be written as pq?
02-19-2016
, 07:49 AM
Quote:
[IMG][/IMG]
Hi friends!,
I'm supposed to implement the above algorithm to produce a pseudo random bit stream, but I'm slightly confused about the first part.
i'm guessing i can use the xth bit of the clock to get a "random bit" in order to generate my seed?
but how do u "randomly" select 2 primes s.t. pq=3 mod4?, don't u have to already have a list of primes? or is it more a case of compute a list of number in the form 4x+3? and check if they can be written as pq?
[/IMG]Hi friends!,
I'm supposed to implement the above algorithm to produce a pseudo random bit stream, but I'm slightly confused about the first part.
i'm guessing i can use the xth bit of the clock to get a "random bit" in order to generate my seed?
but how do u "randomly" select 2 primes s.t. pq=3 mod4?, don't u have to already have a list of primes? or is it more a case of compute a list of number in the form 4x+3? and check if they can be written as pq?
let's say i have a list of primes < some security parameter lambda, how do I "randomly" select them using only the entropy of the seed, say the system clock? say i need to call it more than once within a second, won't i get the same seed more than once?
Last edited by CyberShark93; 02-19-2016 at 08:00 AM.
02-19-2016
, 10:23 AM
Quote:
Despite the thought that we are talking past each other, I think we have a fundamental disagreement.
My suggestion is that data integrity simply deals on the data storage level. I strongly disagree that what happens at the database level has anything at all to do with what happens on the code level. A well-designed database owes no consideration to what the code does with it, what kind of services use it, nor does the quantity of services matter.
Data integrity has a very simple definition: data is to be unique, non-redundant, and non-anomalous. This is not "my" definition. This is "the" definition. There is no such thing as a "flexible" and "expressive" schema design. Just like static languages are concerned with a certain class of mistakes, data integrity deals with a certain class of mistakes. For example, you have have a constraint table of valid country names (which will prevent misspellings), but you can't have a constraint table on ensuring a customer is joined to the correct country. The former is data integrity, the ladder is probably what you mean by business logic. This, of course, can only be solved by code or by human, and even so, there is no guarantees that the data is valid as it is the very expression of the uncertainty principal.
At the fundamental level, data storage is a very different concept than the languages that call it, whether that language is SQL, Python, C, or whatever. The languages you use to call and manipulate the data is a personal choice, but once again, has nothing at all to do with data integrity.
I think I'm confused by exactly what you mean by business logic. If you mean computing values and aggregates from a database, I don't think there is much debate here, but this, once again, is not a data issue, IMO.
Perhaps I'm just confused because I'm very comfortable working at the raw database level, and I don't see the problem from the same abstractions others do?
My suggestion is that data integrity simply deals on the data storage level. I strongly disagree that what happens at the database level has anything at all to do with what happens on the code level. A well-designed database owes no consideration to what the code does with it, what kind of services use it, nor does the quantity of services matter.
Data integrity has a very simple definition: data is to be unique, non-redundant, and non-anomalous. This is not "my" definition. This is "the" definition. There is no such thing as a "flexible" and "expressive" schema design. Just like static languages are concerned with a certain class of mistakes, data integrity deals with a certain class of mistakes. For example, you have have a constraint table of valid country names (which will prevent misspellings), but you can't have a constraint table on ensuring a customer is joined to the correct country. The former is data integrity, the ladder is probably what you mean by business logic. This, of course, can only be solved by code or by human, and even so, there is no guarantees that the data is valid as it is the very expression of the uncertainty principal.
At the fundamental level, data storage is a very different concept than the languages that call it, whether that language is SQL, Python, C, or whatever. The languages you use to call and manipulate the data is a personal choice, but once again, has nothing at all to do with data integrity.
I think I'm confused by exactly what you mean by business logic. If you mean computing values and aggregates from a database, I don't think there is much debate here, but this, once again, is not a data issue, IMO.
Perhaps I'm just confused because I'm very comfortable working at the raw database level, and I don't see the problem from the same abstractions others do?
02-19-2016
, 10:47 AM
02-19-2016
, 10:55 AM
02-19-2016
, 11:51 AM