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  • SQL SERVER – Create Primary Key with Specific Name when Creating Table

    - by pinaldave
    It is interesting how sometimes the documentation of simple concepts is not available online. I had received email from one of the reader where he has asked how to create Primary key with a specific name when creating the table itself. He said, he knows the method where he can create the table and then apply the primary key with specific name. The attached code was as follows: CREATE TABLE [dbo].[TestTable]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL) GO ALTER TABLE [dbo].[TestTable] ADD  CONSTRAINT [PK_TestTable] PRIMARY KEY CLUSTERED ([ID] ASC) GO He wanted to know if we can create Primary Key as part of the table name as well, and also give it a name at the same time. Though it would look very normal to all experienced developers, it can be still confusing to many. Here is the quick code that functions as the above code in one single statement. CREATE TABLE [dbo].[TestTable]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL CONSTRAINT [PK_TestTable] PRIMARY KEY CLUSTERED ([ID] ASC) ) GO Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Constraint and Keys, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • MySQL foreign key constraint disappearing

    - by Bramjam
    This is my table: /* oefenreeks leerplan */ CREATE TABLE leerplan_oefenreeks ( leerplan_oefenreeks_id INT PRIMARY KEY AUTO_INCREMENT NOT NULL, leerplan_id INT NOT NULL, oefenreeks_id INT NOT NULL, plaats INT NOT NULL ); /* fk */ ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT fk_leerp_oefenr_leerplan FOREIGN KEY(leerplan_id) REFERENCES leerplan (leerplan_id) ON DELETE CASCADE; ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT fk_leerp_oefenr_oefenreeks FOREIGN KEY(oefenreeks_id) REFERENCES oefenreeks (oefenreeks_id) ON DELETE CASCADE; /* when I execute the nexline, my fk_leerp_oefenr_leerplan constraint vanishes/disappears*/ ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT un_leerp_oefenr UNIQUE(leerplan_id, oefenreeks_id); ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT un_leerp_oefenr_plaats UNIQUE(leerplan_id, plaats); When I go and check only 3 constraints exist. fk_leerp_oefenr_leerplan disappears. I don't understand why this happens.

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  • Mysql Constraint problem

    - by Bramjam
    this is my table /* oefenreeks leerplan */ CREATE TABLE leerplan_oefenreeks ( leerplan_oefenreeks_id INT PRIMARY KEY AUTO_INCREMENT NOT NULL, leerplan_id INT NOT NULL, oefenreeks_id INT NOT NULL, plaats INT NOT NULL ); /* fk */ ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT fk_leerp_oefenr_leerplan FOREIGN KEY(leerplan_id) REFERENCES leerplan (leerplan_id) ON DELETE CASCADE; ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT fk_leerp_oefenr_oefenreeks FOREIGN KEY(oefenreeks_id) REFERENCES oefenreeks (oefenreeks_id) ON DELETE CASCADE; /* unique s *//*when I execute the nexline, my fk_leerp_oefenr_leerplan constraint vanishes/disappears*/ ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT un_leerp_oefenr UNIQUE(leerplan_id, oefenreeks_id); ALTER TABLE leerplan_oefenreeks ADD CONSTRAINT un_leerp_oefenr_plaats UNIQUE(leerplan_id, plaats); when I go and check only 3 constraints exist (fk_leerp_oefenr_leerplan is gone) I don't understand why this happens, plz tell me (if you need more info just ask ;)

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  • Generating Unique Content - How to Do it For Your Website

    Well, the first question is, why do you need to have unique content on your website? It's really all down to the search engines; they want original content which ends in unique results, thus making it a much better experience for the users and hopefully ensuring that they will return to the site again.

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  • mysql composite unique on FK's

    - by m2o
    I want to implement the following constraints in mysql: create table TypeMapping( ... constraint unique(server_id,type_id), constraint foreign key(server_id) references Server(id), constraint foreign key(type_id) references Type(id) ); This throws a 'ERROR 1062 (23000): Duplicate entry '3-4' for key 'server_id'' when I issue an insert/update that would break the constraint. Is this type of constraint even possible? If so how? Thank you.

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  • counting unique values based on multiple columns

    - by gooogalizer
    I am working in google spreadsheets and I am trying to do some counting that takes into consideration cell values across multiple cells in each row. Here's my table: |AUTHOR| |ARTICLE| |VERSION| |PRE-SELECTED| ANDREW GOLF STREAM 1 X ANDREW GOLF STREAM 2 X ANDREW HURRICANES 1 JOHN CAPE COD 1 X JOHN GOLF STREAM 1 (Google doc here) Each person can submit multiple articles as well as multiple versions of the same article. Sometimes different people submit different articles that happen to be identically named (Andrew and John both submitted different articles called "Golf Stream"). Multiple versions written by the same person do not count as unique, but articles with the same title written by different people do count as unique. So, I am looking to find a formula that Counts the number of unique articles that have been submitted [4] (without having to manually create extra columns for doing CONCATS, if possible) It would also be great to find formulas that: Count the number of unique articles that have been pre-selected (marked "X" in "PRE-SELECTED" column) [2] Count the number of unique articles that have only 1 version [4] Count the number of unique articles that have more than 1 of their versions pre-selected 1 Thank you so much! Nikita

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  • Rhino Mocks, AssertWasCalled with Arg Constraint on array parameter

    - by Etienne Giust
    Today, I had a hard time unit testing a function to make sure a Method with some array parameters was called. Method to be called : void AddUsersToRoles(string[] usernames, string[] roleNames);   I had previously used Arg<T>.Matches on complex types in other unit tests, but for some reason I was unable to find out how to apply the same logic with an array of strings.   It is actually quite simple to do, T really is a string[], so we use Arg<string[]>. As for the Matching part, a ToList() allows us to leverage the lambda expression.   sut.PermissionServices.AssertWasCalled(                 l => l.AddUsersToRoles(                     Arg<string[]>.Matches(a => a.ToList().First() == UserId.ToString())                     ,Arg<string[]>.Matches(a => a.ToList().First() == expectedRole1 && a.ToList()[1] == expectedRole2)                     )                     );   Of course, iw we expect an array with 2 or more values, the math would be something like : a => a.ToList()[0] == value1 && a.ToList()[1] == value2    … etc.

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  • Handling Constraint Violations and Errors in SQL Server

    The database developer can, of course, throw all errors back to the application developer to deal with, but this is neither kind nor necessary. How errors are dealt with is dependent on the application, but the process itself isn't entirely obvious. Compress live data by 73% Red Gate's SQL Storage Compress reduces the size of live SQL Server databases, saving you disk space and storage costs. Learn more.

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  • Entity and pattern validation vs DB constraint

    - by Joerg
    When it comes to performance: What is the better way to validate the user input? If you think about a phone number and you only want numbers in the database, but it could begin with a 0, so you will use varchar: Is it better to check it via the entity model like this: @Size(min = 10, max = 12) @Digits(fraction = 0, integer = 12) @Column(name = "phone_number") private String phoneNumber; Or is it better to use on the database side a CHECK (and no checking in the entity model) for the same feature?

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  • Python - Why use anything other than uuid4() for unique strings?

    - by orokusaki
    I see quit a few implementations of unique string generation for things like uploaded image names, session IDs, et al, and many of them employ the usage of hashes like SHA1, or others. I'm not questioning the legitimacy of using custom methods like this, but rather just the reason. If I want a unique string, I just say this: >>> import uuid >>> uuid.uuid4() 07033084-5cfd-4812-90a4-e4d24ffb6e3d And I'm done with it. I wasn't very trusting before I read up on uuid, so I did this: >>> import uuid >>> s = set() >>> for i in range(5000000): # That's 5 million! >>> s.add(uuid.uuid4()) ... ... >>> len(s) 5000000 Not one repeater (I didn't expect one considering the odds are like 1.108e+50, but it's comforting to see it in action). You could even half the odds by just making your string by combining 2 uuid4()s. So, with that said, why do people spend time on random() and other stuff for unique strings, etc? Is there an important security issue or other regarding uuid?

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  • how to generate unique numbers less than 8 characters long.

    - by loudiyimo
    hi I want to generate unique id's everytime i call methode generateCustumerId(). The generated id must be 8 characters long or less than 8 characters. This requirement is necessary because I need to store it in a data file and schema is determined to be 8 characters long for this id. Option 1 works fine. Instead of option 1, I want to use UUID. The problem is that UUID generates an id which has to many characters. Does someone know how to generate a unique id which is less then 99999999? option 1 import java.util.HashSet; import java.util.Random; import java.util.Set; public class CustomerIdGenerator { private static Set<String> customerIds = new HashSet<String>(); private static Random random = new Random(); // XXX: replace with java.util.UUID public static String generateCustumerId() { String customerId = null; while (customerId == null || customerIds.contains(customerId)) { customerId = String.valueOf(random.nextInt(89999999) + 10000000); } customerIds.add(customerId); return customerId; } } option2 generates an unique id which is too long public static String generateCustumerId() { String ownerId = UUID.randomUUID().toString(); System.out.println("ownerId " + ownerId); return ownerId }

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  • How to map string keys to unique integer IDs?

    - by Marek
    I have some data that comes regularily as a dump from a data souce with a string natural key that is long (up to 60 characters) and not relevant to the end user. I am using this key in a url. This makes urls too long and user unfriendly. I would like to transform the string keys into integers with the following requirements: The source dataset will change over time. The ID should be: non negative integer unique and constant even if the set of input keys changes preferrably reversible back to key (not a strong requirement) The database is rebuilt from scratch every time so I can not remember the already assigned IDs and match the new data set to existing IDs and generate sequential IDs for the added keys. There are currently around 30000 distinct keys and the set is constantly growing. How to implement a function that will map string keys to integer IDs? What I have thought about: 1. Built-in string.GetHashCode: ID(key) = Math.Abs(key.GetHashCode()) is not guaranteed to be unique (not reversible) 1.1 "Re-hashing" the built-in GetHashCode until a unique ID is generated to prevent collisions. existing IDs may change if something colliding is added to the beginning of the input data set 2. a perfect hashing function I am not sure if this can generate constant IDs if the set of inputs changes (not reversible) 3. translate to base 36/64/?? does not shorten the long keys enough What are the other options?

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  • Count unique visitors by group of visited places

    - by Mathieu
    I'm facing the problem of counting the unique visitors of groups of places. Here is the situation: I have visitors that can visit places. For example, that can be internet users visiting web pages, or customers going to restaurants. A visitor can visit as much places as he wishes, and a place can be visited by several visitors. A visitor can come to the same place several times. The places belong to groups. A group can obviously contain several places, and places can belong to several groups. Given that, for each visitor, we can have a list of visited places, how can I have the number of unique visitors per group of places? Example: I have visitors A, B, C and D; and I have places x, y and z. I have these visiting lists: [ A -> [x,x,y,x], B -> [], C -> [z,z], D -> [y,x,x,z] ] Having these number of unique visitors per place is quite easy: [ x -> 2, // A and D visited x y -> 2, // A and D visited y z -> 2 // C and D visited z ] But if I have these groups: [ G1 -> [x,y,z], G2 -> [x,z], G3 -> [x,y] ] How can I have this information? [ G1 -> 3, // A, C and D visited x or y or z G2 -> 3, // A, C and D visited x or z G3 -> 2 // A and D visited x or y ] Additional notes : There are so many places that it is not possible to store information about every possible group; It's not a problem if approximation are made. I don't need 100% precision. Having a fast algorithm that tells me that there were 12345 visits in a group instead of 12543 is better than a slow algorithm telling the exact number. Let's say there can be ~5% deviation. Is there an algorithm or class of algorithms that addresses this type of problem?

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  • Non-unique display names?

    - by Davy8
    I know of at least big title game (Starcraft II) that doesn't require unique display names, so it would seem like it can work in at least some circumstance. Under what situations does allowing non-unique display names work well? When does it not work well? Does it come down to whether or not impersonation of someone else is a problem? The reasons I believe it works for Starcraft II is that there isn't any kind of in-game trading of virtual goods and other than "for kicks" there isn't much incentive to impersonate someone else in the game. There's also ladder rankings so even trying to impersonate a pro is easily detectable unless you're on a similar skill level. What are some other cases where it makes sense to specifically allow or disallow duplicate display names? (I have no idea what to tag this as. I went with game-design because I needed at least 1 tag and I don't have rep to create new ones yet.)

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  • Inexpensive generation of hierarchical unique IDs

    - by romaninsh
    My application is building a hierarchical structure like this: root = { 'id': 'root', 'children': [ { 'name': 'root_foo', 'children': [] }, { 'id': 'root_foo2', 'children': [ { 'id': 'root_foo2_bar', 'children': [] } ] } ] } in other words, it's a tree of nodes, where each node might have child elements and unique identifier I call "id". When a new child is added, I need to generate a unique identifier for it, however I have two problems: identifiers are getting too long adding many children takes slower, as I need to find first available id My requirement is: naming of a child X must be determined only from the state in their ancestors When I re-generate tree with same contents, the IDs must be same or in other words, when we have nodes A and B, creating child in A, must not affect the name given to children of B. I know that one way to optimize would be to introduce counter in each node and append it to the names which will solve my performance issue, but will not address the issue with the "long identifiers". Could you suggest me the algorithm for quickly coming up with new IDs?

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  • Grails- Unique constraint

    - by WaZ
    How can I basically carry out a unique constraint on a string data-type field. class User{ String username String Email static hasMany = [roles:Roles] static constraints = { Email(email:true) username(unique:true) } Is there any simple way to implement username(unique:true) or I will have to manually check the database by the in-built methods like .findByNameLike. My need is that username should be unique and should be case insensitive

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  • Unique Constraint At Data Level in GAE

    - by Ngu Soon Hui
    It seems that the unique constraint is not natively supported in GAE, although one can enforce unique check before putting an object to store. But that was in January 2009, what about now? Can I specify unique constraint on a column during schema creation? i.e. class Account(db.Model): name = db.StringProperty() email = db.StringProperty() as unique # something like this @classmethod def create(cls, name, email): a = Account(name=name, email=email) a.put() return a

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  • Symfony FK Constraint Issue

    - by Daniel Hertz
    Hello! So I have a table schema that has users who can be friends. User: actAs: { Timestampable: ~ } columns: name: { type: string(255), notnull: true } email: { type: string(255), notnull: true, unique: true } nickname: { type: string(255), unique: true } password: { type: string(300), notnull: true } image: { type: string(255) } FriendsWith: actAs: { Timestampable: ~ } columns: friend1_id: { type: integer, primary: true } friend2_id: { type: integer, primary: true } relations: User: { onDelete: CASCADE, local: friend1_id, foreign: id } User: { onDelete: CASCADE, local: friend2_id, foreign: id } It builds the database correctly, but when I try to insert test data like: User: user1: name: Danny Gurt email: [email protected] nickname: danny password: test1 user2: name: Adrian Soian email: [email protected] nickname: adrian password: test1 FriendsWith: friendship1: friend1_id: user1 friend2_id: user2 I get this integrity constraint problem: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`krowdd`.`friends_with`, CONSTRAINT `friends_with_ibfk_1` FOREIGN KEY (`friend1_id`) REFERENCES `user` (`id`) ON DELETE CASCADE) Any ideas? Thanks!

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  • Altering constraint delete action

    - by Hobhouse
    I did this: ALTER TABLE `db`.`my_table` ADD CONSTRAINT FOREIGN KEY (`my_second_table_id`) REFERENCES `my_second_table` (`id`); I should have done this: ALTER TABLE `db`.`my_table` ADD CONSTRAINT FOREIGN KEY (`my_second_table_id`) REFERENCES `my_second_table` (`id`) ON DELETE SET NULL; Is it possible to ALTER this, or do I have to drop the constraint and add again?

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  • NSArrayController that is sorted and unique (no duplicates) for use in a pop-up in a core-data app

    - by Douglas Weaver
    I have core data app with an entity OBSERVATION that has as one of its attributes DEALNAME. I want to reference through Interface Builder or by making custom modifications to an NSArrayController a list of unique sorted dealnames so that I can use them in a pop-up. I have attempted to use @distinctUnionOfSets (and @distinctUnionOfArrays) but am unable to locate the proper key sequence. I can sort the ArrayController by providing a sort descriptor, but do not know how to eliminate duplicates. Are the @distinct... keys the right methodology? It would seem to provide the easiest way to optimize the use of IB. Is there a predicate form for removing duplicates? Or do I need to use my custom controller to extract an NSSet of the specific dealnames, put them back in an array and sort it and reference the custom array from IB? Any help would be appreciated. I am astounded that other have not tried to create a sorted-unique pop-up in tableviews.

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  • Trying to modify a constraint in PostgresSQL

    - by MISMajorDeveloperAnyways
    Postgres is getting quite annoying lately. I have checked the documentation provided by Oracle and found a way to do this without dropping the table. Problem is, it errors out at modify as it does not recognize the keyword. Using EMS SQL Manager for PostgreSQL. Alter table public.public_insurer_credit MODIFY CONSTRAINT public_insurer_credit_fk1 deferrable, initially deferred; I was able to work around it by dropping the constraint using : ALTER TABLE "public"."public_insurer_credit" DROP CONSTRAINT "public_insurer_credit_fk1" RESTRICT; ALTER TABLE "public"."public_insurer_credit" ADD CONSTRAINT "public_insurer_credit_fk1" FOREIGN KEY ("branch_id", "order_id", "public_insurer_id") REFERENCES "public"."order_public_insurer"("branch_id", "order_id", "public_insurer_id") ON UPDATE CASCADE ON DELETE NO ACTION DEFERRABLE INITIALLY DEFERRED;

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  • adding month to EndDate as constraint in Oracle SQL

    - by user2900611
    I've a question regarding Oracle database SQL. my employee each have a project, the end date of the project depends on the no of months that was given to them base on PTerm. Am i right to do it this way? CREATE TABLE PROJECT ( P_ID VARCHAR ( 20 ) NOT NULL, PNAME VARCHAR ( 100 ) NOT NULL, PTERM VARCHAR ( 20 ), PSTARTDATE DATE, PENDDATE DATE, CONSTRAINT PROJECT_PKEY PRIMARY KEY ( P_ID ), CONSTRAINT PROJECT_PTERM CHECK ( PTERM IN ('1 MONTH', '2 MONTH', '3 MONTH') ), CONSTRAINT PROJECT_ENDDATE CHECK ( PENDDATE = (PSTARTDATE + PTERM) ) );

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  • Application that provides unique keys to multiple threads

    - by poly
    Thanks all for your help before. So, this is what I came up with so far, the requirements are, application has two or more threads and each thread requires a unique session/transaction ID. is the below considered thread safe? thread 1 will register itself with get_id by sending it's pid thread 2 will do the same then thread 1 & 2 will call the function to get a unique ID function get_id(bool choice/*register thread or get id*/, pid_t pid) { static int pid[15][1]={0};//not sure if this work, anyway considor any it's been set to 0 by any other way than this static int total_threads = 0; static int i = 0; int x=0,y=0; if (choice) // thread registeration part { for(x=0;x<15;x++) { if (pid[x][0]==0); { pid[x][0] = (int) pid; pid[x][1] = (x & pidx[x][1]) << 24;//initiate counter for this PID by shifting x to the 25th bit, it could be any other bit, it's just to set a range. //so the range will be between 0x0000000 and 0x0ffffff, the second one will be 0x1000000 and 0x1ffffff, break; } total_threads++; } } //search if pid exist or not, if yes return transaction id for(x=0;x<15;x++) { if (pid[x][0]==pid); { pid[x][1]++;//put some test here to reset the number to 0 if it reaches 0x0ffffff return pid[x][1]; break; } } }

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  • Microsoft lance System Center : une plate-forme unique et complète pour l'administration systèmes

    Microsoft® System Center est une plate-forme unique et complète pour l'administration des postes de travail, des serveurs, des applications et des périphériques, en environnement physique ou virtuel. Citation: La gamme de produits System Center a pour but de simplifier les opérations et les changements, de réduire les durées de dépannage et d'améliorer les capacités de planification au sein de votre entreprise dans une optique de réduction des coûts. Optimisée pour une administration système dynamique, System Center vous aide à fournir le niv...

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