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  • How to create unique user key

    - by Grayson Mitchell
    Scenario: I have a fairly generic table (Data), that has an identity column. The data in this table is grouped (lets say by city). The users need an identifier in order for printing on paper forms, etc. The users can only access their cites data, so if they use the identity column for this purpose they will see odd numbers (e.g. a 'New York' user might see 1,37,2028... as the listed keys. Idealy they would see 1,2,3... (or something similar) The problem of course is concurrency, this being a web application you can't just have something like: UserId = Select Count(*)+1 from Data Where City='New York' Has anyone come up with any cunning ways around this problem?

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  • How to represent a 3-way relation with JPA?

    - by simpatico
    A user may have several labels, and links. Then, a user associates a label (or more) to a link. How does one represent the later relationship? A solution could be a many-to-many relationship btw user and link with the optional attribute label. http://en.wikibooks.org/wiki/Java_Persistence/ManyToMany#Mapping_a_Join_Table_with_Additional_Columns In this case the relationship btw user and label may better be 'virtual'. Any alternative I'm not seeing? PS: I've used google bookmarks terminology, as it matches my case quite well.

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  • what does "out of range" mean?

    - by user329820
    Hi I have checked these statements with mysql and no error will happen and also the out put will be 0 rows BUT my friend checked it and he found an error for SELECT becaouse it is out of range !! IS he correct? thanks CREATE TABLE T1(A INTEGER NULL); SELECT * FROM T1;

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  • How to change data structure in mysql using mysqldump without deleting files

    - by Don Quixote
    Essentially what I'm trying to do is sync a production server with a sandbox server, but only the table structures and stored procedures. The procedures aren't any problem since they can be overriden, but the problem is the tables. I want to sync and alter their structures on the production server using mysqldump (or any other way that you can propose) without altering any existing data. If it helps, I only want to add more columns, not remove any existing ones. Also, I am using mysqlyog. Is there any way to do this?

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  • Good basic tutorial for installing and using SqlServer

    - by ripper234
    I know mysql, and I'd like to learn sqlserver. I'm currently stuck on the basics of basics: How to install and configure sql server How to connect to it I installed Sql Server through Web Platform Installer, and have Visual Studio 2008 installed. Still, I can't understand how to connect to my server: I see that the SQL service itself (SQLEXPRESS) is running in both in services.msc and Sql Server Configuration Manager I try to connect to it via the Management Studio, but I don't understand what to do. Where do I begin?

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  • retrieving the record which has only one value

    - by ashwani66476
    Hello All, Please suggest me a query, which retrieves only those record which has the single row in table. For Example table1. name age aaa 20 bbb 10 ccc 20 ddd 30 If I run "select distinct age from table1. result will be age 20 10 30 But I need a query, which give the result like name age bbb 10 ddd 30 Thanks....

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  • When/Why to use Cascading in SQL Server?

    - by Joel Coehoorn
    When setting up foreign keys in SQL Server, under what circumstances should you have it cascade on delete or update, and what is the reasoning behind it? This probably applies to other databases as well. I'm looking most of all for concrete examples of each scenario, preferably from someone who has used them successfully.

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  • using dummy row with NOT NULL to solve DEFAUT NULL

    - by Tony38
    I know having DEFAULT NULLS is not a good practice but I have many optional lookup values which are FK in the system so to solve this issue here is what i am doing: I use NOT NULL for every FK / lookup valve field. I have the first row in every table which is PK id = 1 as a dummy row with just "none" in all the columns. this way I can use NOT NULL in my schema and if needed reference to the none row values which should be null. Is this a good design or any other work arounds?

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  • Storing user settings in table - how?

    - by Mdillion
    I have settings for the user about 200 settings, these include notice settings and tracing settings from user activities on objects. The problem is how to store it in the DB? Should each setting be a row or a column? If colunm then table will have 200 colunms. If row then about 3 colunms but 200 rows per user x even 10 million users = not good. So how else can i store all these settings? NOTE: these settings are a mix of text entry and FK lookups to other tables. Thanks.

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  • What's the best way to test MSSQL connection programmatically?

    - by backslash17
    I need to develop a single routine that will be fired each 5 minutes to check if a list of MSSQL servers (10 to 12) are up and running. I can try to obtain a simple query in each one of the servers but this means that I have to create a table, view or stored procedure in every server, even if I use any already made SP I need to have a registered user in each server too. The servers are not in the same phisical location so having those requirements would be a complex task. Is there a way to simply "ping" from c# one MSSQL server? Thanks in advance!

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  • get n records at a time from a temporary table

    - by Claudiu
    I have a temporary table with about 1 million entries. The temporary table stores the result of a larger query. I want to process these records 1000 at a time, for example. What's the best way to set up queries such that I get the first 1000 rows, then the next 1000, etc.? They are not inherently ordered, but the temporary table just has one column with an ID, so I can order it if necessary. I was thinking of creating an extra column with the temporary table to number all the rows, something like: CREATE TEMP TABLE tmptmp AS SELECT ##autonumber somehow##, id FROM .... --complicated query then I can do: SELECT * FROM tmptmp WHERE autonumber>=0 AND autonumber < 1000 etc... how would I actually accomplish this? Or is there a better way? I'm using Python and PostgreSQL.

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  • Can I set ignore_dup_key on for a primary key?

    - by Mr. Flibble
    I have a two-column primary key on a table. I have attempted to alter it to set the ignore_dup_key to on with this command: ALTER INDEX PK_mypk on MyTable SET (IGNORE_DUP_KEY = ON); But I get this error: Cannot use index option ignore_dup_key to alter index 'PK_mypk' as it enforces a primary or unique constraint. How else should I set IGNORE_DUP_KEY to on?

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  • FKs on all tables for status colunm

    - by Jonarch
    I have a colunm "Status" in every table in my DB. The purpose of it is to show if the given row is in use or if it has been deactivated. So values can be (0=deactive and 1= active). Two ways I see this: I can have enums or I am thinking if it is better to keep this colunm as a FK which references the main system data dictionary table which has all the codes used on the system. (website) The benefit is every table, every row can then be centralized through this FK. So if i ever want to check all rows which are deactive on my system i can from this table as all th child tables will have like status = ID 233, where 233 = deactive in the data dictionary table. Any benefit or should i stick with the old way of enums?. Also I am thinking if i need one more status for deleted or is that same as deactivated?

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  • Three-way full outer join in SQLite

    - by Vince
    I have three tables with a common key field, and I need to join them on this key. Given SQLite doesn't have full outer or right joins, I've used the full outer join without right join technique on Wikipedia with much success. But I'm curious, how would one use this technique to join three tables by a common key? What are the efficiency impacts of this (the current query takes about ten minutes)? Thanks!

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  • Solr autocommit and autooptimize?

    - by Camran
    I will be uploading my website to a VPS soon. It is a classifieds website which uses Solr integrated with MySql. Solr is updated whenever a new classified is put or deleted. I need a way to make the commit() and optimize() be automated, for example once every 3 hours or so. How can I do this? (Details Please) When is it ideal to optimize? Thanks

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  • cakephp - form for belongsTo Model

    - by user1511579
    I createt the following model to link 2 relational tables: class Ficha extends AppModel { //public $useTable = 'ficha_seg'; var $primaryKey = 'id_ficha'; var $name = 'Ficha'; var $belongsTo = array( 'Perigo' => array( 'className' => 'Perigo', 'foreignKey' => false, 'conditions' => 'Perigo.id_fichas = Ficha.id_ficha' ) ); } Now, i have a form that requires data from the class Ficha, and then is redirected to another ctp page where i will input the data for the table "Perigos". However, since i'm still a newbie in cakephp i'm having difficult building that second form to insert the data on the table "Perigos". Here goes the code i built at the moment related to the second form: FichasController.php (the method where is it supposed to save the data on the table "Perigos": public function preencher_ficha(){ if ($this->request->is('ficha')) { $this->Ficha->create(); if ($this->Ficha->Perigo->save($this->request->data)) { $last_id=$this->Ficha->getLastInsertID(); $this->Session->setFlash('Your post has been updated '.$last_id.'.'); //$this->redirect(array('action' => 'preencher_ficha')); } else { $this->Session->setFlash('Unable to qualquer coisa your post.'); } } } The preencher_ficha.ctp file with the form: echo $this->Form->create('Ficha->Perigo', array('action' => 'index')); echo $this->Form->input('class_subst', array('label' => 'Classificação:')); echo $this->Form->input('simbolos_perigo', array('label' => 'Símbolos:')); echo $this->Form->input('frases_r', array('label' => 'Frases:')); echo $this->Form->end('Finalizar Ficha'); Here i guess the create part is wrong, but i think i have errors too in the controller part.

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  • What is the differnce between an Oracle and Microsoft schema?

    - by Tarzan
    I am working on an enterprise project. Some of the team has an Oracle background and some has a Microsoft SQL Server background. There is much confusion when we talk about schemas. I am trying to provide some clarity. Is this an accurate way to describe the difference in the meaning of schemas between the two technologies? An Oracle schema is associated with a single user and consists of the objects owned by the user. A MS SQL Server schema schema is a namespace.

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