Like Angel'o'sphere said, if you can adapt your database, the problem becomes trivial. Make sure that at least for a given customer, each subsequent transaction ID is greater than the prior transaction ID (if this is not already the case, then add a new field populated by a sequence so that you have a field where it is the case).
Here's the solution with a sub-select (because it's easier to read, it can be converted to a join for efficiency): SELECT
transactions.fieldNames FROM transactions WHERE
(transactions.customerID, transactions.transactionID) IN (
SELECT customerID, MAX(transactionID)
FROM transactions
GROUP BY customerID
)
If, as you suggest, you need it for specific date ranges, then add those to the sub-select. Like I said, for most RDBMS's this would be faster if converted to a join (and basically every sub-select can be converted to a join). For some RDBMS's they would convert it to a join as part of the execution planning anyway (I believe Postgres and Oracle do this).
Arguments like these actually only serve to strengthen RDBMS's case over NoSQL. Database engineers have been solving these problems easily and efficiently for years, but a new generation likes to think in new patterns. Not that there's anything wrong with that - except there is a certain tendency to try to put a square peg in a round hole, a complaint when it doesn't fit right, and a sigh from the guys who've been carving pegs so they fit snugly all along.
Key/value storage does have advantages over traditional RDBMS designs (assuming the RDBMS is designed and utilized properly), but those advantages are things like linear scalability, and very few cases where a task on the K/V side is substantially faster to complete than a properly designed solution on the RDBMS side - at least not until you are talking tens or hundreds of billions of records on 100+ CPU clusters (this is the linear scalability advantage).
It depends on the kids' age, needs, and temperment. My daughter is 10 months old; her basket weaving skills have not yet surpassed her basket eating skills.
This makes me think that even with net neutrality rules in place, that probably won't cover bandwidth allowances for consumers (which are easily defensible for ISP's). If net neutrality goes into effect and doesn't cover allowances, ISP's will simply create different bandwidth buckets.
Imagine an IS such as Comcast offering "Unlimited Tier 1 Connectivity," with some extremely low tier 2 connectivity limit. Anyone who doesn't pay the Comcast tax would have their traffic stuck in tier 2 - competing for an extremely tiny slice of the consumer's allowance and effectively disqualifying video services and so forth.
Unsurprisingly, Samsung professes that the claim itself (of keylogger software being installed) is outrageous. According to them, it's a false positive caused by the inclusion of the Slovene language, which gets included in a "SL" folder in C:\windows. Apparently the existence of a folder with this name is all that's needed to make VIPRE flag you as having StarLogger installed, which they demonstrate by creating an empty "SL" folder in C:\Windows.
No, we have seen users cross multiple A-class networks from page view to page view - often even the page request comes from one IP, and the request for images or scripts on the same page comes from a different one. This is typical for people with load balanced public connections - the load is spread across multiple providers. For example, a Level-3 connection and a Verizon connection. Looking exclusively at IP address and/or timing, there is no way you could guess they were the same user, and any tolerance level which allows for this scenario (which we have observed organically from legitimate users) doesn't actually provide any level of lock-down at all.
I think you missed the point. Not only does it fail to provide any protection in the most likely interception scenario, but for that lack of protection, it also breaks the site for legitimate users. A little added security for no user inconvenience is ok - as long as you're realistic about the small protections it offers, but it's decidedly less ok when real users find they're unable to use your site as a result.
You can make it harder to pick the locks (sniff session tokens) by nailing your front door shut (signing session tokens with user IP), but what good is that if you have an open window next to the door (it doesn't protect against the easiest form of the attack), except inconvenience those who would have gone through the front door (normal users)?
It's called SNI (Server Name Indication), it's part of the SSL standard, and has been supported in Apache since 2.2.12. The virtual host name is submitted as part of the TLS negotiations so the server knows which certificate to use.
You cannot depend on the user's IP address not changing. Besides offering only some additional security (most people subject to having their session sniffed are using the same public WiFi as the user - so they'll actually have the same IP address), more importantly, some users have load-balanced outbound Internet access.
On our own network, we see legitimate single sessions bridging multiple A-class networks. Page request to page request they will have an IP address from a wholly different ISP, which can even geolocate to wildly different locations. Admittedly that's the exception rather than the rule, but it's also becoming more common - especially for people on mobile networks, whose IP address is subject to whichever cell tower is giving them the strongest signal right now. Users sitting relatively equidistant from multiple towers can flip between various IP's rather frequently.
The only things you can reliably depend on not changing in the user's request (for legitimate users) are also all spoofable by illegitimate users. For example, you can depend on a cookie not changing unless you told it to change, but it can be spoofed; you can depend on the user agent not changing, but it can be spoofed, and so forth.
There is no way to make an unspoofable session cookie; you can only prevent interception by using a secure standard such as SSL.
Yep, you can start listening a few seconds after you start the download. This is the usual method for me; buy the book in the app, and start listening a few seconds later no matter where I am. It's actually easier to buy the book from the app than it is on the website (just tap "Buy Book using 1 credit" and confirm).
The Android version does have bookmarks and chapter marks as well, and you can choose from different formats to download from the settings. It also has listening statistics and some kind of pseudo "achievement" system (things like for total listening time, library size, listening all night, listening for X hours in a row, and so forth). You can see screenshots of some of that stuff here: https://market.android.com/details?id=com.audible.application I'm not familiar with the iOS version, so I don't know how similar they are, but when I looked at the app in the iTunes store, there weren't any screenshots to compare against.
Hmm, Audible on Android has no compunction about downloading over the cell network. I have a NexusOne running on AT&T, and downloaded a 300mb book yesterday morning. There is a setting that lets you choose whether you only download on WiFi so you don't accidentally use up your data plan, but it defaulted to disabled (downloads with any connection).
The counterweights exactly equal the mass of the elevator plus whatever passengers are on board? Must play hell with the system when people take the elevator up but take the stairs down.
This may sound trollish, but I don't intend it to be; rather I ask this question because of my own ignorance of the subject. What is it about Ham radios which make them a better (or less disaster prone) communication platform than modern satellite based communication? The only thing I can think of which would affect ground communications and satellite communications at the same time would be a massive solar storm; and it seems to me that ham radios would be taken out under such a disaster just like all other electronics.
A straw man is by definition uncalled for. All tools are abusable, the fact that a tool can be abused does not mean it should be discarded. It is up to parents to make a decision about their child's developmental progress and make the best call they are able to about how to effectively guide their child. Some parents will allow their child more freedom than I would in their same circumstances. Some parents will allow their child less. Still, I am not more qualified to make parenting decisions about their child than they are.
You seem to suppose that I must be able to understand that children do have a right to privacy. I don't believe this at all. Children do not; at least not from their parents. But you can be a bad parent if you don't give them some according to their ability to handle it responsibly.
I have a daughter who is nine months old. She gets no privacy whatsoever. I regularly see her naked while changing a diaper or giving her a bath, and there is no activity I permit her to do without my approval. At some point between this age and when she's an adult, she will have gained the right to as much privacy as she chooses to exercise and is able to realize. It would be bad parenting if I still treat her at age 17 as though she's still an infant. But it would also be bad parenting if I grant her the same privileges and independence as I would grant a 17 year old. A responsible parent understands their child's development and grants them enough privileges to enable them to grow, but not so many that the consequences of mistakes are disastrous.
So just because you imagine a 17 year old kid whose parents grant them no privacy at all doesn't mean that there isn't plenty of reason some younger child should be denied privacy in their earliest forays online.
Very well said! Every time a story like this comes up, you get people like GP who say, "If you are so out of touch with what your kid does online..." These statements are ironic in the true sense though; the author self-admits that you should be keeping tabs on your kid (by suggesting you're doing it wrong if you're not), then lashes out at tools which enable this in the same breath. It strikes me as a surprising lack of critical thinking.
There seems to be some sort of confusion in the sense that people don't recognize that protective actions by parents are necessarily suggested for every kid of every age until the day they turn 18. Somehow they fail to realize that most parents actually are reasoning adults who are capable of making decisions about when it is and isn't appropriate to give children privacy. They simply see a tool which could be abused and therefore assume this is its only intent, and that therefore makes the tool unjustified (demonstrated so by construction of a straw man example of a child who has outgrown the need for the tool).
Children do in fact not have the same rights as adults. This is correct and appropriate. As they approach adulthood, they should be granted more and more of those rights by their parents, according to that child's development.
The real affront in this article is that this isn't a very effective way to keep an eye on your kids. The assumption is that a keystroke logger will pierce the children's activity. If the child wants to keep something secret, they will only use the monitored computer for updates they're ok sharing, while they use a school, library, or friend's computer for anything else. If you keep the monitoring secret, it represents dishonesty with your child (which might be necessary, but should be avoided except when there's an extenuating circumstance). If kept entirely secret, it will probably do an adequate job for a while, but that secret is ruined the first time you act in any way on the knowledge it provides.
Instead for things like social networks, if you feel your child should be monitored, you should require access to their profile, and you should require that you know who each of their friends are. Especially at younger ages, presuming many parents are acting the same way, this knowing who each of the friends are prevents proxy identities from being effective (other children will not be able to explain who the proxy is, so they can't friend the proxy, and the proxy is therefore of no value).
Children do not have a right to privacy in what they do online. Eventually of course you have to trust your children, but this should manifest by less and less frequent checking of their activity, not by never having checked in the first place.
You wrongly assume that I want those government services at those prices in the first place. I don't. I would gladly not pay taxes and in return not get any services from the government.
There are plenty of places in the world you can move to to take advantage of such a situation, I suggest you do so.
I don't disagree with you, but I had to ride public transit 1.5hrs each way for my coop job while I was in school because I couldn't afford a car.
My reward? Graduating with $50k in debt as opposed to $100k in debt.
Owning & using a car doesn't cost $25,000 per year unless you are driving something expensive or an extremely long distance. You can buy and operate a brand new car for 2 years, fuel and maintenance included, for less than that.
His point though, was that some people would engage in the same level of frugality as you, and over that time might still have a hard time saving up $10k. Some people live near to or even below the poverty line. For some people, $10k is two year's salary, before expenses.
Which would have nothing to do with eReader or not, it would have to do with font size. The research authors might be interested to know the technology to print words with various sized fonts has existed for some time now.
He's not pushing security through obscurity. He's pushing fear plus "security through giving us your money." His claim is a clear conflict of interest.
Did you know dangerous radio waves are passing through your brain every minute? Buy my special tinfoil hat to protect yourself!
The public doesn't know for sure, but there's a whole lot of really strong evidence that's surfaced in the last week that they're announcing the Verizon iPhone this Tuesday (Jan 11), with a release date of later this month.
It's no guarantee of course, but there's a lot of oddly specific independent corroboration (including invites addressed to specific Apple-focused tech reporters instead of the news org itself, and no invite to Gizmodo [whom Apple has cut off from all events after the iPhone 4 leak]). Even WSJ has said that's what Tuesday's announcement is about (they've historically been right on this sort of thing).
A 2 point market share lead according to Nielsen is "a lot"? Both reports are within 3 points of each other. But while Apple is growing less than 1 point per quarter, Google is growing around 6.5 points. According to either report, if the trends exhibited through November continued, Google would be ahead of Apple by today anyway.
It'll be interesting to see what the Verizon iPhone does for iOS. I don't know if it was legal obligations or what, but Apple being kept off the largest carrier has hurt them a lot, and allowed Android to build up a lot of momentum I'm pretty sure it wouldn't have had otherwise.
Slashdot Mirror
Like Angel'o'sphere said, if you can adapt your database, the problem becomes trivial. Make sure that at least for a given customer, each subsequent transaction ID is greater than the prior transaction ID (if this is not already the case, then add a new field populated by a sequence so that you have a field where it is the case).
Here's the solution with a sub-select (because it's easier to read, it can be converted to a join for efficiency):
SELECT
transactions.fieldNames
FROM transactions
WHERE
(transactions.customerID, transactions.transactionID) IN (
SELECT customerID, MAX(transactionID)
FROM transactions
GROUP BY customerID
)
If, as you suggest, you need it for specific date ranges, then add those to the sub-select. Like I said, for most RDBMS's this would be faster if converted to a join (and basically every sub-select can be converted to a join). For some RDBMS's they would convert it to a join as part of the execution planning anyway (I believe Postgres and Oracle do this).
Arguments like these actually only serve to strengthen RDBMS's case over NoSQL. Database engineers have been solving these problems easily and efficiently for years, but a new generation likes to think in new patterns. Not that there's anything wrong with that - except there is a certain tendency to try to put a square peg in a round hole, a complaint when it doesn't fit right, and a sigh from the guys who've been carving pegs so they fit snugly all along.
Key/value storage does have advantages over traditional RDBMS designs (assuming the RDBMS is designed and utilized properly), but those advantages are things like linear scalability, and very few cases where a task on the K/V side is substantially faster to complete than a properly designed solution on the RDBMS side - at least not until you are talking tens or hundreds of billions of records on 100+ CPU clusters (this is the linear scalability advantage).
It depends on the kids' age, needs, and temperment. My daughter is 10 months old; her basket weaving skills have not yet surpassed her basket eating skills.
This makes me think that even with net neutrality rules in place, that probably won't cover bandwidth allowances for consumers (which are easily defensible for ISP's). If net neutrality goes into effect and doesn't cover allowances, ISP's will simply create different bandwidth buckets.
Imagine an IS such as Comcast offering "Unlimited Tier 1 Connectivity," with some extremely low tier 2 connectivity limit. Anyone who doesn't pay the Comcast tax would have their traffic stuck in tier 2 - competing for an extremely tiny slice of the consumer's allowance and effectively disqualifying video services and so forth.
Unsurprisingly, Samsung professes that the claim itself (of keylogger software being installed) is outrageous. According to them, it's a false positive caused by the inclusion of the Slovene language, which gets included in a "SL" folder in C:\windows. Apparently the existence of a folder with this name is all that's needed to make VIPRE flag you as having StarLogger installed, which they demonstrate by creating an empty "SL" folder in C:\Windows.
No, we have seen users cross multiple A-class networks from page view to page view - often even the page request comes from one IP, and the request for images or scripts on the same page comes from a different one. This is typical for people with load balanced public connections - the load is spread across multiple providers. For example, a Level-3 connection and a Verizon connection. Looking exclusively at IP address and/or timing, there is no way you could guess they were the same user, and any tolerance level which allows for this scenario (which we have observed organically from legitimate users) doesn't actually provide any level of lock-down at all.
I think you missed the point. Not only does it fail to provide any protection in the most likely interception scenario, but for that lack of protection, it also breaks the site for legitimate users. A little added security for no user inconvenience is ok - as long as you're realistic about the small protections it offers, but it's decidedly less ok when real users find they're unable to use your site as a result.
You can make it harder to pick the locks (sniff session tokens) by nailing your front door shut (signing session tokens with user IP), but what good is that if you have an open window next to the door (it doesn't protect against the easiest form of the attack), except inconvenience those who would have gone through the front door (normal users)?
It's called SNI (Server Name Indication), it's part of the SSL standard, and has been supported in Apache since 2.2.12. The virtual host name is submitted as part of the TLS negotiations so the server knows which certificate to use.
You cannot key sessions against a single IP address, IP addresses are subject to change during legitimate user sessions (see http://tech.slashdot.org/comments.pl?sid=2047006&cid=35559588).
You cannot depend on the user's IP address not changing. Besides offering only some additional security (most people subject to having their session sniffed are using the same public WiFi as the user - so they'll actually have the same IP address), more importantly, some users have load-balanced outbound Internet access.
On our own network, we see legitimate single sessions bridging multiple A-class networks. Page request to page request they will have an IP address from a wholly different ISP, which can even geolocate to wildly different locations. Admittedly that's the exception rather than the rule, but it's also becoming more common - especially for people on mobile networks, whose IP address is subject to whichever cell tower is giving them the strongest signal right now. Users sitting relatively equidistant from multiple towers can flip between various IP's rather frequently.
The only things you can reliably depend on not changing in the user's request (for legitimate users) are also all spoofable by illegitimate users. For example, you can depend on a cookie not changing unless you told it to change, but it can be spoofed; you can depend on the user agent not changing, but it can be spoofed, and so forth.
There is no way to make an unspoofable session cookie; you can only prevent interception by using a secure standard such as SSL.
Yep, you can start listening a few seconds after you start the download. This is the usual method for me; buy the book in the app, and start listening a few seconds later no matter where I am. It's actually easier to buy the book from the app than it is on the website (just tap "Buy Book using 1 credit" and confirm).
The Android version does have bookmarks and chapter marks as well, and you can choose from different formats to download from the settings. It also has listening statistics and some kind of pseudo "achievement" system (things like for total listening time, library size, listening all night, listening for X hours in a row, and so forth). You can see screenshots of some of that stuff here: https://market.android.com/details?id=com.audible.application I'm not familiar with the iOS version, so I don't know how similar they are, but when I looked at the app in the iTunes store, there weren't any screenshots to compare against.
Hmm, Audible on Android has no compunction about downloading over the cell network. I have a NexusOne running on AT&T, and downloaded a 300mb book yesterday morning. There is a setting that lets you choose whether you only download on WiFi so you don't accidentally use up your data plan, but it defaulted to disabled (downloads with any connection).
The counterweights exactly equal the mass of the elevator plus whatever passengers are on board? Must play hell with the system when people take the elevator up but take the stairs down.
=)
This may sound trollish, but I don't intend it to be; rather I ask this question because of my own ignorance of the subject. What is it about Ham radios which make them a better (or less disaster prone) communication platform than modern satellite based communication? The only thing I can think of which would affect ground communications and satellite communications at the same time would be a massive solar storm; and it seems to me that ham radios would be taken out under such a disaster just like all other electronics.
More accurately a lot of developers are taking great pains to keep IE6 reasonably functional because they don't want to give up that market share.
All this article demonstrates is:
I successfully used http://code.google.com/p/reduxcomputing-proximity/ for this purpose under OS X. Have not looked to see if there's something for Windows.
A straw man is by definition uncalled for. All tools are abusable, the fact that a tool can be abused does not mean it should be discarded. It is up to parents to make a decision about their child's developmental progress and make the best call they are able to about how to effectively guide their child. Some parents will allow their child more freedom than I would in their same circumstances. Some parents will allow their child less. Still, I am not more qualified to make parenting decisions about their child than they are.
You seem to suppose that I must be able to understand that children do have a right to privacy. I don't believe this at all. Children do not; at least not from their parents. But you can be a bad parent if you don't give them some according to their ability to handle it responsibly.
I have a daughter who is nine months old. She gets no privacy whatsoever. I regularly see her naked while changing a diaper or giving her a bath, and there is no activity I permit her to do without my approval. At some point between this age and when she's an adult, she will have gained the right to as much privacy as she chooses to exercise and is able to realize. It would be bad parenting if I still treat her at age 17 as though she's still an infant. But it would also be bad parenting if I grant her the same privileges and independence as I would grant a 17 year old. A responsible parent understands their child's development and grants them enough privileges to enable them to grow, but not so many that the consequences of mistakes are disastrous.
So just because you imagine a 17 year old kid whose parents grant them no privacy at all doesn't mean that there isn't plenty of reason some younger child should be denied privacy in their earliest forays online.
Very well said! Every time a story like this comes up, you get people like GP who say, "If you are so out of touch with what your kid does online..." These statements are ironic in the true sense though; the author self-admits that you should be keeping tabs on your kid (by suggesting you're doing it wrong if you're not), then lashes out at tools which enable this in the same breath. It strikes me as a surprising lack of critical thinking.
There seems to be some sort of confusion in the sense that people don't recognize that protective actions by parents are necessarily suggested for every kid of every age until the day they turn 18. Somehow they fail to realize that most parents actually are reasoning adults who are capable of making decisions about when it is and isn't appropriate to give children privacy. They simply see a tool which could be abused and therefore assume this is its only intent, and that therefore makes the tool unjustified (demonstrated so by construction of a straw man example of a child who has outgrown the need for the tool).
Children do in fact not have the same rights as adults. This is correct and appropriate. As they approach adulthood, they should be granted more and more of those rights by their parents, according to that child's development.
The real affront in this article is that this isn't a very effective way to keep an eye on your kids. The assumption is that a keystroke logger will pierce the children's activity. If the child wants to keep something secret, they will only use the monitored computer for updates they're ok sharing, while they use a school, library, or friend's computer for anything else. If you keep the monitoring secret, it represents dishonesty with your child (which might be necessary, but should be avoided except when there's an extenuating circumstance). If kept entirely secret, it will probably do an adequate job for a while, but that secret is ruined the first time you act in any way on the knowledge it provides.
Instead for things like social networks, if you feel your child should be monitored, you should require access to their profile, and you should require that you know who each of their friends are. Especially at younger ages, presuming many parents are acting the same way, this knowing who each of the friends are prevents proxy identities from being effective (other children will not be able to explain who the proxy is, so they can't friend the proxy, and the proxy is therefore of no value).
Children do not have a right to privacy in what they do online. Eventually of course you have to trust your children, but this should manifest by less and less frequent checking of their activity, not by never having checked in the first place.
You wrongly assume that I want those government services at those prices in the first place. I don't. I would gladly not pay taxes and in return not get any services from the government.
There are plenty of places in the world you can move to to take advantage of such a situation, I suggest you do so.
Owning & using a car doesn't cost $25,000 per year unless you are driving something expensive or an extremely long distance. You can buy and operate a brand new car for 2 years, fuel and maintenance included, for less than that.
His point though, was that some people would engage in the same level of frugality as you, and over that time might still have a hard time saving up $10k. Some people live near to or even below the poverty line. For some people, $10k is two year's salary, before expenses.
get you anywhere close to 2/3rds of your paycheck
The final income tax bill? 49%
49% is close to 2/3's? Seems like there ought to be a closer reasonable approximation we could make there, if we look hard enough.
Which would have nothing to do with eReader or not, it would have to do with font size. The research authors might be interested to know the technology to print words with various sized fonts has existed for some time now.
He's not pushing security through obscurity. He's pushing fear plus "security through giving us your money." His claim is a clear conflict of interest.
Did you know dangerous radio waves are passing through your brain every minute? Buy my special tinfoil hat to protect yourself!
Merchants are not permitted to request ID by their merchant agreement with the credit card companies.
Lots of places ask for it anyway, because they're who's out cash if a charge is successfully disputed. But you are not required to show ID.
The public doesn't know for sure, but there's a whole lot of really strong evidence that's surfaced in the last week that they're announcing the Verizon iPhone this Tuesday (Jan 11), with a release date of later this month.
It's no guarantee of course, but there's a lot of oddly specific independent corroboration (including invites addressed to specific Apple-focused tech reporters instead of the news org itself, and no invite to Gizmodo [whom Apple has cut off from all events after the iPhone 4 leak]). Even WSJ has said that's what Tuesday's announcement is about (they've historically been right on this sort of thing).
A 2 point market share lead according to Nielsen is "a lot"? Both reports are within 3 points of each other. But while Apple is growing less than 1 point per quarter, Google is growing around 6.5 points. According to either report, if the trends exhibited through November continued, Google would be ahead of Apple by today anyway.
It'll be interesting to see what the Verizon iPhone does for iOS. I don't know if it was legal obligations or what, but Apple being kept off the largest carrier has hurt them a lot, and allowed Android to build up a lot of momentum I'm pretty sure it wouldn't have had otherwise.