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• Reliable way of generating unique hardware ID

  - by mr.b

  Question: what's the best way to accomplish following. I have to come up with unique ID for each networked client, such that: it (ID) should persist once client software is installed on target computer, and should continue to persist if software is re-installed on same computer and same OS installment, it should not change if hardware configuration is modified in most ways (except changing the motherboard) When hard drive with client software installed is cloned to another computer with identical hardware configuration (or, as similar as possible), client software should be aware of that change. A little bit of explanation and some back-story: This question is basically age old question that also touches topic of software copy-protection, as some of mechanisms used in that area are mentioned here. I should be clear at this point that I'm not looking for a copy-protection scheme. Please, read on. :) I'm working on a client-server software that is supposed to work in local network. One of problems I have to solve is to identify each unique client in network (not so much of a problem), so that I can apply certain attributes to every specific client, retain and enforce those attributes during deployment lifetime of a specific client. While I was looking for a solution, I was aware of following: Windows activation system uses some kind of heavy fingerprinting mechanism, that is extremely sensitive to hardware modifications, Disk imaging software copies along all Volume IDs (tied to each partition when formatted), and custom, uniquely generated IDs during installation process, during first run, or in any other way, that is strictly software in its nature, and stored in registry or on hard drive, so it's very easy to confuse two Obvious choice for this kind of problem would be to find out BIOS identifiers (not 100% sure if this is unique through identical motherboard models, though), as that's the only thing I can rely on, that isn't duplicated, transferred by cloning, and that can't be changed (at least not by using some user-space program). Everything else fails as either being not reliable (MAC cloning, anyone?), or too demanding (in terms that it's too sensitive to configuration changes). Am I missing something obvious here? Sub-question that I'd like to ask is, am I doing it correctly, architecture-wise? Perhaps there is a better tool for task that I have to accomplish... Another approach I had in mind is something similar to handshake mechanism, where server maintains internal lookup table of connected client IDs (which can be even completely software-based and non-unique at any given moment), and tells client to come up with different ID during handshake, if duplicate ID is provided upon connection. That approach, unfortunately, doesn't play nicely with one of requirements to tie attributes to specific client during lifetime.

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• hibernate get unique field result

  - by cometta

  i use below to get unique "departmentCode" , but by using distinct, my list only return 'departmentCode' all other fields are not retrieved from table, how to retrieve other fields as well like 'divisionCode' and make sure 'departmentCode' is always unique? DetachedCriteria crit = DetachedCriteria.forClass(Company.class); crit.setProjection(Projections.distinct(Projections.property("departmentCode")));

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• Addthis: Sharing for unique items on page

  - by Espen Arnoy

  I am using addthis (addthis.com) to offer sharing on items listed on a page (stage.hverdagskupp.no). Since each item on the page is unique, I want the shared information to be unique as well. However, facebook and twitter only seems to allow global page information to be shared. Anyone knows how to define item specific sharing information with addthis, for facebook and twitter?

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• Unique partition ID

  - by BlueMan

  I'm looking for same way to get an unique ID of every partition in Win OS. Also for flash drives (SD cards, pendrives, etc.) connected to PC. I think that after formatting they get an unique ID - like MAC, right? Also I want to get other information of that partition - it's name, file system, size, etc.

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• not unique ids in a route in Rails

  - by Victor P

  In a blog in Rails I want to have paths like http://mydomain.com/posts/28383/comments#21 This is the 21st comment of the 28383th post. The 21 is not an unique id, but the pair 28383, #21 is unique. How can I do this in Rails? Do I have to change the routes? the model? I will be very thankful if you can point me in the right direction Thanks

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• Unique id of a column

  - by Kayes

  Hi. Does each column of a table in SQL Server have a unique id? I've looked into sys.columns and the column_id there is merely the order of the columns which changes if the order of the column is changed. I'd like to know if SQL Server maintains a unique id for each column as it does for each table and other objects. And if it does, how can I get that? Thanks.

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• Insert the lowest possible unique positve integer in an atomic fashion in MySql

  - by Jason Christa

  Say I have a table with a unique positive integer field. I currently have rows with id's of [1, 2, 3, 4, 5, 8, 12, 35]. Is there a insert query that I could write that would assign the id field to the lowest unique positive integer (in this case 6)? It would have to do this atomically so there isn't the possibility of concurrent inserts wiping out each other or failing.

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• How to add an unique valued attribute to every tag in the xml using XSL

  - by Rachel

  I want to add a unique attribute say "ind" to every tag in the xml. How do i do it using xsl. It need'nt be a sequence number. As long it is unique for every tag it is sufficient. Input:Some textSome other textSome other text Expected output: Some textSome other textSome other text

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• How to use Unique Composite Key

  - by LifeH2O

  I have a table Item(ItemName*, ItemSize*, Price, Notes) I was making composite key of (ItemName,ItemSize) to uniquely identify item. And now after reading some answers on stackoverflow suggesting the use of UNIQUE i revised it as Item(ItemID*, ItemName, ItemSize, Price, Notes) But How to apply UNIQUE constraint on ItemName and ItemSize please correct if there is something wrong in question

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• Creating a unique URL safe hash

  - by Ben Foster

  I want to hash/encode a unique integer (database ID) to create a similarly unique string. It needs to meet the following requirements: Must start with a letter or number, and can contain only letters and numbers. All letters in a container name must be lowercase. Must be from 3 through 63 characters long (although the shorter the better) The result does not need to be reversible, just repeatable - so a 1-way hash would be fine.

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• Should I create a unique clustered index, or non-unique clustered index on this SQL 2005 table?

  - by Bremer

  I have a table storing millions of rows. It looks something like this: Table_Docs ID, Bigint (Identity col) OutputFileID, int Sequence, int …(many other fields) We find ourselves in a situation where the developer who designed it made the OutputFileID the clustered index. It is not unique. There can be thousands of records with this ID. It has no benefit to any processes using this table, so we plan to remove it. The question, is what to change it to… I have two candidates, the ID identity column is a natural choice. However, we have a process which does a lot of update commands on this table, and it uses the Sequence to do so. The Sequence is non-unique. Most records only contain one, but about 20% can have two or more records with the same Sequence. The INSERT app is a VB6 piece of crud throwing thousands insert commands at the table. The Inserted values are never in any particular order. So the Sequence of one insert may be 12345, and the next could be 12245. I know that this could cause SQL to move a lot of data to keep the clustered index in order. However, the Sequence of the inserts are generally close to being in order. All inserts would take place at the end of the clustered table. Eg: I have 5 million records with Sequence spanning 1 to 5 million. The INSERT app will be inserting sequence’s at the end of that range at any given time. Reordering of the data should be minimal (tens of thousands of records at most). Now, the UPDATE app is our .NET star. It does all UPDATES on the Sequence column. “Update Table_Docs Set Feild1=This, Field2=That…WHERE Sequence =12345” – hundreds of thousands of these a day. The UPDATES are completely and totally, random, touching all points of the table. All other processes are simply doing SELECT’s on this (Web pages). Regular indexes cover those. So my question is, what’s better….a unique clustered index on the ID column, benefiting the INSERT app, or a non-unique clustered index on the Sequence, benefiting the UPDATE app?

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• JQuery $.unique() issue ie

  - by vanzylv

  Hi Guys var arr = new Array(); arr[0] = 'Departmental News' arr[1] = 'Departmental News' arr[2] = 'Another Cat' arr[3] = 'Another Cat' arr[4] = 'Departmental News' alert(arr) alert($.unique(arr)) In IE I get duplicates. In any other browser only the unique ones Any Ideas?

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• mysql update unique index

  - by atno

  Is there a way to say UPDATE items SET qty=10 WHERE **unique key** instead of saying UPDATE items SET qty=10 WHERE userID=1 AND listID=10 and itemID=100 on the following table? CREATE TABLE IF NOT EXISTS `items` ( `userID` int(20) NOT NULL, `listID` int(20) NOT NULL, `itemID` int(20) NOT NULL, `qty` int(10) NOT NULL, UNIQUE KEY `unique` (`userID`,`listID`,`itemID`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

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• How to create a unique web page address in ASP.NET

  - by Jim

  Is there a standard way to create unique web page address in ASP.NET? I'm sending surveys to customers and will be including a link to the web page. For example: http://www.mysurveypages.foo/survey/UniqueID I would then customize the survey based on who I sent it to. I know it can be done by passing in a unique parameter to a page but I curious about doing it this way.

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• How to enforce unique field value in java Google App Engine

  - by supercobra

  Hello there, I am try to find out how to enforce uniqueness in fields other than the unique id. Example: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class User implements IsSerializable { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Long id; @Persistent private String name; @Persistent private String email; // <= I want this to be unique as well } In the example above, how can I enforce uniqueness of the email value across the database? Daniel

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• unique substrings using suffix tree

  - by user1708762

  For a given string S of length n- Optimal algorithm for finding all unique substrings of S can't be less than O(n^2). So, the best algorithm will give us the complexity of O(n^2). As per what I have read, this can be implemented by creating suffix tree for S. The suffix tree for S can be created in O(n) time. Now, my question is- How can we use the suffix tree for S to get all the unique substrings of S in O(n^2)?

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• Are same IP address with different submask unique?

  - by xEnOn

  In a same block of IPv4 addresses, can there be same IPs with different submasks? For example, can I have this: 180.70.65.140/26 180.70.65.140/25 180.70.65.140/24 All the 3 addresses above have the same numbers but different subnet mask. Are all the 3 addresses distinct of their own? In other words, 180.70.65.140/25 belongs to User A, 180.70.65.140/25 belongs to User B and 180.70.65.140/24 belongs to User C? After applying the submask, their network addresses look like this: 180.70.65.140/26 --> 180.70.65.128/26 180.70.65.140/25 --> 180.70.65.128/25 180.70.65.140/24 --> 180.70.65.0/24 If the addresses are recognised uniquely, how is it so? How would each of the these addresses being recognised to be unique? I am thinking like once I have 180.70.65.140/26, I can't reuse the same numbers of 180.70.65.140 again but since classless is meant to increase the number of IP addresses, it would do much if I can't reuse.

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• Check for unique rows, but ignore one particular column

  - by user269148

  I have an XML document, that looks like this: Column A to S with headers, and there are 1922 rows. This is an backup of some SMS, and I want to get rid of duplicates. The problem is, that the Time in the readable_date header has been messed up. There is nothing wrong with the date, but the clock time is wrong, so I have split that column in three, with Year, day and clock. I know I can use a standard filter, but it only looks for unique rows in a single column. What I want to perform, is to make a row check similar to this: F(x)=Check if Column 2A to (infinate) is equal to Column 3A to (infinate), but ignore column(R). IF True, then delete Column 3A to (infinate) Otherwise Check IF column 2A to (infinate) is equal Column 4A to (infinate) and so on. I need to ignore a particular column in a row every time, and need to do this for a complete sheet. And the formula check should apply for every row, when the first one is done checking for duplicates... If anyone else has a better solution, please say so. Anyway, anyone who can help?

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• MySQL Unique hash insertion

  - by Jesse

  So, imagine a mysql table with a few simple columns, an auto increment, and a hash (varchar, UNIQUE). Is it possible to give mysql a query that will add a column, and generate a unique hash without multiple queries? Currently, the only way I can think of to achieve this is with a while, which I worry would become more and more processor intensive the more entries were in the db. Here's some pseudo-php, obviously untested, but gets the general idea across: while(!query("INSERT INTO table (hash) VALUES (".generate_hash().");")){ //found conflict, try again. } In the above example, the hash column would be UNIQUE, and so the query would fail. The problem is, say there's 500,000 entries in the db and I'm working off of a base36 hash generator, with 4 characters. The likelyhood of a conflict would be almost 1 in 3, and I definitely can't be running 160,000 queries. In fact, any more than 5 I would consider unacceptable. So, can I do this with pure SQL? I would need to generate a base62, 6 char string (like: "j8Du7X", chars a-z, A-Z, and 0-9), and either update the last_insert_id with it, or even better, generate it during the insert. I can handle basic CRUD with MySQL, but even JOINs are a little outside of my MySQL comfort zone, so excuse my ignorance if this is cake. Any ideas? I'd prefer to use either pure MySQL or PHP & MySQL, but hell, if another language can get this done cleanly, I'd build a script and AJAX it too. Thanks!

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• Generating all unique combinations for "drive ya nuts" puzzle

  - by Yuval A

  A while back I wrote a simple python program to brute-force the single solution for the drive ya nuts puzzle. The puzzle consists of 7 hexagons with the numbers 1-6 on them, and all pieces must be aligned so that each number is adjacent to the same number on the next piece. The puzzle has ~1.4G non-unique possibilities: you have 7! options to sort the pieces by order (for example, center=0, top=1, continuing in clockwise order...). After you sorted the pieces, you can rotate each piece in 6 ways (each piece is a hexagon), so you get 6**7 possible rotations for a given permutation of the 7 pieces. Totalling: 7!*(6**7)=~1.4G possibilities. The following python code generates these possible solutions: def rotations(p): for i in range(len(p)): yield p[i:] + p[:i] def permutations(l): if len(l)<=1: yield l else: for perm in permutations(l[1:]): for i in range(len(perm)+1): yield perm[:i] + l[0:1] + perm[i:] def constructs(l): for p in permutations(l): for c in product(*(rotations(x) for x in p)): yield c However, note that the puzzle has only ~0.2G unique possible solutions, as you must divide the total number of possibilities by 6 since each possible solution is equivalent to 5 other solutions (simply rotate the entire puzzle by 1/6 a turn). Is there a better way to generate only the unique possibilities for this puzzle?

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• Need to find number of new unique ID numbers in a MySQL table

  - by Nicholas

  I have an iPhone app out there that "calls home" to my server every time a user uses it. On my server, I create a row in a MySQL table each time with the unique ID (similar to a serial number) aka UDID for the device, IP address, and other data. Table ClientLog columns: Time, UDID, etc, etc. What I'd like to know is the number of new devices (new unique UDIDs) on a given date. I.e. how many UDIDs were added to the table on a given date that don't appear before that date? Put plainly, this is the number of new users I gained that day. This is close, I think, but I'm not 100% there and not sure it's what I want... SELECT distinct UDID FROM ClientLog a WHERE NOT EXISTS ( SELECT * FROM ClientLog b WHERE a.UDID = b.UDID AND b.Time <= '2010-04-05 00:00:00' ) I think the number of rows returned is the new unique users after the given date, but I'm not sure. And I want to add to the statement to limit it to a date range (specify an upper bound as well).

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• Spring Data Neo4J @Indexed(unique = true) not working

  - by Markus Lamm

  I'm new to Neo4J and I have, probably an easy question. There're NodeEntitys in my application, a property (name) is annotated with @Indexed(unique = true) to achieve the uniqueness like I do in JPA with @Column(unique = true). My problem is, that when I persist an entity with a name that already exists in my graph, it works fine anyway. But I expected some kind of exception here...?! Here' s an overview over basic my code: @NodeEntity public abstract class BaseEntity implements Identifiable { @GraphId private Long entityId; ... } public class Role extends BaseEntity { @Indexed(unique = true) private String name; ... } public interface RoleRepository extends GraphRepository<Role> { Role findByName(String name); } @Service public class RoleServiceImpl extends BaseEntityServiceImpl<Role> implements { private RoleRepository repository; @Override @Transactional public T save(final T entity) { return getRepository().save(entity); } } And this is my test: @Test public void testNameUniqueIndex() { final List<Role> roles = Lists.newLinkedList(service.findAll()); final String existingName = roles.get(0).getName(); Role newRole = new Role.Builder(existingName).build(); newRole = service.save(newRole); } That's the point where I expect something to go wrong! How can I ensure the uniqueness of a property, without checking it for myself?? THANKS IN ADVANCE FOR ANY IDEAS!! P.S.: I'm using neo4j 1.8.M07, spring-data-neo4j 2.1.0.BUILD-SNAPSHOT and Spring 3.1.2.RELEASE.

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• How to make a 100% UNIQUE dvd? [closed]

  - by sajawikio

  Is it possible to make a DVD which would be next to impossible to replicate exactly even with special equipment? To be clear, not in the sense of making the data itself resistant to piracy - nothing like that. More like as an analogy to antiques - a reproduction of a furniture would be able to be spotted to a trained eye, that it is not the original. Is it possible to do this for a dvd? Like, say a dvd is copied, even by someone who is trying to use even special equipment and is hypothetically dying to copy the dvd exactly for whatever reason - even such copied dvd would be detectable that it is not exactly the original dvd somehow (as if it were a reproduction of an original antique, but not the original), and would be almost or even preferably impossible to actually copy 100% exact the dvd ever again. Just some ideas below on the sort of thing i might go about doing to do this, but really am not sure how or what programs, media, hardware, etc. would do the trick Not sure what would do the trick -- but for instance do there exist any blank dvd's that already come pre-recorded with some sort of serial number or bar code, or other metadata, or an encrypted hash, or something like that? Maybe any blank dvd will do but i should get a special software to extract hardcoded metadata? If so which software? Or special hardware even maybe? Such dvd which the "secret" can be: Well, to know what the "secret" is and if it is present on the disk, it probably should be readable by some software or maybe a particular hardware (i guess preferably only if some sort of key is known and input into the software, even better, only then such secret data on disk can be read, otherwise nothing shows up and it looks like just a regular disk with no secret on it), and Would be impossible to actually replicate, especially not with regular burning hardware and preferably not at all. Other idea: Is there any special software that can direct the write head of laser to physically "mar" the dvd in such a way that, when played in dvd player, makes a particular visual pattern or something like that, also say the mar itself shows up as faint scratch on disk, but would be impossible for someone to do themselves exactly? EDIT: Also to clarify suppose the dvd contains video and music that should be playable on dvd players, maybe a menu too (i.e not a dvd containing software), and also to clarify the question is about how to make dvd 100% unique, not how to make the actual content of dvd protected from "piracy".

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• Check if Database raises a particular exception

  - by mcabral

  using Nhibernate; I'm trying to insert several values a on table which has an unique index on some columns. I'd like to know if a particular insert raises an exception for having violated the unique constraint. So, which particular exception type should i catch? I only want to catch this particular one and let all others go up. Thanks a lot!

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• How to get numeric random uniqueid in MS sql server

  - by Rajesh Rolen- DotNet Developer

  i am using sql server 2005, please tell me how can i get 6 digits (unique numeric which should be random) value for every row in table. i have a field in table in which i needs 6 digit numeric value (random and unique). please help me to do this.

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