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  • KD-Trees and missing values (vector comparison)

    - by labratmatt
    I have a system that stores vectors and allows a user to find the n most similar vectors to the user's query vector. That is, a user submits a vector (I call it a query vector) and my system spits out "here are the n most similar vectors." I generate the similar vectors using a KD-Tree and everything works well, but I want to do more. I want to present a list of the n most similar vectors even if the user doesn't submit a complete vector (a vector with missing values). That is, if a user submits a vector with three dimensions, I still want to find the n nearest vectors (stored vectors are of 11 dimensions) I have stored. I have a couple of obvious solutions, but I'm not sure either one seem very good: Create multiple KD-Trees each built using the most popular subset of dimensions a user will search for. That is, if a user submits a query vector of thee dimensions, x, y, z, I match that query to my already built KD-Tree which only contains vectors of three dimensions, x, y, z. Ignore KD-Trees when a user submits a query vector with missing values and compare the query vector to the vectors (stored in a table in a DB) one by one using something like a dot product. This has to be a common problem, any suggestions? Thanks for the help.

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  • Lambda Expressions and Stored Procedures

    - by Jason Summers
    Hi Everyone. I'm trying to mimic the LINQ Where extension method for my ADO.NET DAL methods. Bascially, my aim is to have a single method that I can call. Such as: Product p = Dal.GetProduct(x => x.ProductId == 32); Product p2 = Dal.GetProduct(x => x.ProductName.Contains("Soap")); I then want to dissect those Predicates and send the filter options to parameters in an ADO.NET Stored Procedure call. Any comments greatly appreciated.

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  • Zend_Auth using multiple tables

    - by Christian
    What I'm trying to do is use Zend_Auth for authentication with the issuing being that the 'identity' is stored in a different table then then 'credential.' I'm able to pass an array for the credential and the identity but when it comes to the actual tables I'm not able to get it to accept the array. It ignores the 2nd table name. I was wondering if anyone has ever made this work in this way without extending the Zend_Auth class or if I will need to do so. Thanks in advance.

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  • How can I write this query in Django? (datetime)

    - by alex
    | time_before | datetime | YES | MUL | NULL | | | time_after | datetime | YES | MUL | NULL | | the_tag = Tag.objects.get(id=tag_id) Log.objects.filter(blah).extra(where=['last_updated >'+the_tag.time_before, 'last_updated' < the_tag.time_after]) Ok. Basically, I have an object that's called "the_tag". I want to select from Log where log.last_updated (which is a datetime field) is between the tag's time. But, I don't know how to write the last part of this Django query.

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  • What should be the considerations for choosing SQL/NoSQL?

    - by Yuval A
    Target application is a medium-sized website built to support several hundred-thousand users an hour, with an option to scale above that. Data model is rather simple, and caching potential is pretty high (~10:1 ratio of read to edit actions). What should be the considerations when coming to choose between a relational, SQL-based datastore to a NoSQL option (such as HBase and Cassandra)?

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  • SQL: How do I INSERT primary key values from two tables INTO a master table.

    - by Stefan
    Hello, I would appreciate some help with an SQL statement I really can't get my head around. What I want to do is fairly simple, I need to take the values from two different tables and copy them into an master table when a new row is inserted into one of the two tables. The problem is perhaps best explained like this: I have three tables, productcategories, regioncategories and mastertable. --------------------------- TABLE: PRODUCTCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: BOOKS | Books --------------------------- --------------------------- TABLE: REGIONCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: EU | European Union --------------------------- --------------------------- TABLE: MASTERTABLE --------------------------- COLUMNS: REGION | PRODUCT --------------------------- VALUES: EU | BOOKS --------------------------- I want the values to be inserted like this when a new row is created in either productcategories or regioncategories. New row is created. --------------------------- TABLE: PRODUCTCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: BOOKS | Books --------------------------- VALUES: DVD | DVDs --------------------------- And a SQL statement copies the new values into the mastertable. --------------------------- TABLE: MASTERTABLE --------------------------- COLUMNS: REGION | PRODUCT --------------------------- VALUES: EU | BOOKS --------------------------- VALUES: EU | DVD --------------------------- The same goes if a row is created in the regioncategories. New row. --------------------------- TABLE: REGIONCATEGORIES --------------------------- COLUMNS: CODE | DESCRIPTION --------------------------- VALUES: EU | European Union --------------------------- VALUES: US | United States --------------------------- Copied to the mastertable. --------------------------- TABLE: MASTERTABLE --------------------------- COLUMNS: REGION | PRODUCT --------------------------- VALUES: EU | BOOKS --------------------------- VALUES: EU | DVD --------------------------- VALUES: US | BOOKS --------------------------- VALUES: US | DVD --------------------------- I hope it makes sense. Thanks, Stefan

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  • How to select top n rows from a datatable/dataview in asp.net

    - by skamale
    How to select top n rows from a datatable/dataview in asp.net.currently I am using the following code by passing the table and number of rows to get the records but is there a better way. public DataTable SelectTopDataRow(DataTable dt, int count) { DataTable dtn = dt.Clone(); for (int i = 0; i < count; i++) { dtn.ImportRow(dt.Rows[i]); } return dtn; }

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  • Would this hack for per-object permissions in django work?

    - by Edward
    According to the documentation, a class can have the meta option permissions, described as such: Options.permissions Extra permissions to enter into the permissions table when creating this object. Add, delete and change permissions are automatically created for each object that has admin set. This example specifies an extra permission, can_deliver_pizzas: permissions = (("can_deliver_pizzas", "Can deliver pizzas"),) This is a list or tuple of 2-tuples in the format (permission_code, human_readable_permission_name). Would it be possible to define permissions at run time by: permissions = (("can_access_%s" % self.pk, / "Has access to object %s of type %s" % (self.pk,self.__name__)),) ?

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  • Synchronising local and remote DB

    - by nico
    Hi everyone, I have a general question about DB synchronisation. So, I'm developing a website locally (PHP + MySQL) and I would like to be able to synchronise at least the structure (and maybe the contents) of the two DB when one of the two is changed (normally I would change the local copy). Right now what I'm doing is to use mysqldump to dump the modified tables and then import them in the remote DB or do it by hand if the changes are minimal. However I find this tedious and error-prone. For the PHP I'm currently using Quanta+ which has the handy feature of finding files that have changed and just upload those. Is there something similar for MySQL? Otherwise how do you keep your DBs synchronised? Thanks nico PS: I'm sorry if this was already asked, I saw other questions that deal with similar topics, but couldn't really find an answer.

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  • Event triggering in server-side scripts

    - by Qiao
    In SO, when your question got answer. or you got new badge, event is triggered. Or when you got new PM in forum, it also lets you know by alerting message. You see message that something happened with your account when you enter site for first time after this event. How is this implemented? How do scripts know, that they have something new to show you?

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  • Fastest method for SQL Server inserts, updates, selects from C# ASP.Net 2.0+

    - by Ian
    Hi All, long time listener, first time caller. I use SPs and this isn't an SP vs code-behind "Build your SQL command" question. I'm looking for a high-throughput method for a backend app that handles many small transactions. I use SQLDataReader for most of the returns since forward only works in most cases for me. I've seen it done many ways, and used most of them myself. Methods that define and accept the stored procedure parameters as parameters themselves and build using cmd.Parameters.Add (with or without specifying the DB value type and/or length) Assembling your SP params and their values into an array or hashtable, then passing to a more abstract method that parses the collection and then runs cmd.Parameters.Add Classes that represent tables, initializing the class upon need, setting the public properties that represent the table fields, and calling methods like Save, Load, etc I'm sure there are others I've seen but can't think of at the moment as well. I'm open to all suggestions.

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  • Java MySQL Query Problem MySQLSyntaxErrorException When Creating a Table

    - by Aqib Mushtaq
    I fairly new to MySQL with Java, but I have executed a few successful INSERT queries however cannot seem to get the CREATE TABLE query to execute without getting the 'MySQLSyntaxErrorException' exception. My code is as follows: import java.sql.*; Statement stmt; Class.forName("com.mysql.jdbc.Driver"); String url = "jdbc:mysql://localhost:3306/mysql"; Connection con = DriverManager.getConnection(url, "root", "password"); stmt = con.createStatement(); String tblSQL = "CREATE TABLE IF NOT EXISTS \'dev\'.\'testTable\' (\n" + " \'id\' int(11) NOT NULL AUTO_INCREMENT,\n" + " \'date\' smallint(6) NOT NULL\n" + ") ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;"; stmt.executeUpdate(tblSQL); stmt.close(); con.close(); And the error is as follows: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''dev'.'testTable' ( 'id' int(11) NOT NULL AUTO_INCREMENT, 'date' smallint(6) N' at line 1 I would appreciate it if anyone could spot the mistake in this query, as I've tried executing this within phpMyAdmin and it works as it should. Thanks in advance.

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  • Single HTML Table from multiple MySQL tables

    - by David Chouinard
    Hi! I've been struggling for a while with this one; I'll try to explain it here as simply as possible. Consider this MySQL table: +----------+-----------+---------+--------+ |status_id |session_id |pilot_id |present | +----------+-----------+---------+--------+ |1 |61 |901 |1 | |2 |63 |901 |1 | |3 |62 |901 |0 | |4 |62 |902 |1 | |5 |63 |903 |1 | +----------+-----------+---------+--------+ Both session_id and pilot_id are foreign keys making reference to a primary key in another table. The same pilot_id can be associated with different session_id, but every pilot_id-session_id combination is unique. I need to make an HTML table (in PHP) that would display the data like this: +----------+---------+---------+---------+ | |61 |62 |63 | +----------+---------+---------+---------+ |901 |X | |X | |902 | |X | | |903 | | |X | +----------+---------+---------+---------+ Hence, rows are pilot_id and columns are session_id. When a pilot_id-session_id combination has a present value of 1, the corresponding cell should be checked. (ie. when the row-combination is zero or the combination does not exist in the MySQL table, nothing should appear in the HTML table) Phew. Any ideas? Thanks!

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  • does the order a composite key is defined matter?

    I have a table with (col1,col2) as a composite primary key. create table twokeytable(col1 int,col2 int,constraint twokeytable_pk primary key (col1,col2)); and another table with col3,col4 collumns witha composite foreign key(col3,col4) which references the(col1,col2) primary key. For some processing I need to drop the foreign key and primary constraints .While restoring the constraints does order of the keys matter?. are these same? create table fktwokeytable(col3 int,col4 int,constraint fkaddfaa_fk foreign key(col4,col3) references twokeytable(col1,col2)) and create table fktwokeytable(col3 int,col4 int,constraint fkaddfaa_fk foreign key(col3,col4) references twokeytable(col1,col2))

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  • How do I modify an attribute across all rows in a table?

    - by prgmatic
    Hi folks, My apologies for asking such a novice question but, I need help building a script using either PHP or directly in MySQL that can do the following: Take the values of a column in a table (text) Change them into capitalized words (from "this is a title" to "This Is A Title") Replace the old values (uncapitalized) with the new values (capitalized). Thanks for the help and support.

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  • Multiple table relationships in Zend Help

    - by Zogi
    Hi Guys I have been doing some DB mapping to link two tables to no avail. Everytime I run the code I get the following error: Message: File "Role.php" does not exist or class "Role" was not found in the file Stack trace: #0 C:\wamp\www\zend\library\Zend\Db\Table\Row\Abstract.php(867): Zend_Db_Table_Row_Abstract->_getTableFromString('Role') #1 C:\wamp\www\uw\application\models\admin\User.php(56): Zend_Db_Table_Row_Abstract->findDependentRowset('Role') #2 C:\wamp\www\uw\application\controllers\AdminController.php(110): Application_Model_Admin_User->getUsers() #3 C:\wamp\www\zend\library\Zend\Controller\Action.php(513): AdminController->usersAction() #4 C:\wamp\www\zend\library\Zend\Controller\Dispatcher\Standard.php(289): Zend_Controller_Action->dispatch('usersAction') #5 C:\wamp\www\zend\library\Zend\Controller\Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http)) #6 C:\wamp\www\zend\library\Zend\Application\Bootstrap\Bootstrap.php(97): Zend_Controller_Front->dispatch() #7 C:\wamp\www\zend\library\Zend\Application.php(366): Zend_Application_Bootstrap_Bootstrap->run() #8 C:\wamp\www\uwi\public\index.php(26): Zend_Application->run() #9 {main} Code & DB below: application/models/admin/User.php class Application_Model_Admin_User extends Zend_Db_Table_Abstract { protected $_name = 'user'; protected $_dependentTables = array('Role'); public function getUsers() { $rows = $this->fetchAll($this->select()->where('active = ?', 1)); $rows1 = $rows->current(); $rows2 = $rows1->findDependentRowset('Role'); return $rows2; } } application/models/admin/Role.php class Application_Model_Admin_Role extends Zend_Db_Table_Abstract { protected $_name = 'role'; protected $_referenceMap = array ( 'Role' => array( 'columns' => array('id'), 'refTableClass' => 'User', 'refColumns' => array('role_id') ); } DB tables CREATE TABLE role ( id integer auto_increment NOT NULL, name varchar(120), PRIMARY KEY(id) ); CREATE TABLE user ( id integer auto_increment NOT NULL, username varchar(120), PRIMARY KEY(id), FOREIGN KEY(role_id) REFERENCES role(id) );

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  • Modeling Tools that understand both Relational and LDAP

    - by jm04469
    I am looking to do some modeling and would like to have a tool that can capture not only a relational model like ERWIN but also allow us to easily port to LDAP as an option. NOTE: Visio can connect to an existing LDAP server and draw, but does not allow for you to model first and then deploy, unlike its relational capabilities.

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  • Natural vs surrogate keys on support tables

    - by Bugeo
    I have read many articles about the battle between natural versus surrogate primary keys. I agree in the use of surrogate keys to identify records of tables whose contents are created by the user. But in the case of supporting tables what should I use? For example, in a hypothetical table "orderStates". If you use a natural key would have the following data: TABLE ORDERSTATES {ID: "NEW", NAME: "New"} {ID: "MANAGEMENT" NAME: "Management"} {ID: "SHIPPED" NAME: "Shipped"} If I use a surrogate key would have the following data: TABLE ORDERSTATES {ID: 1 CODE: "NEW", NAME: "New"} {ID: 2 CODE: "MANAGEMENT" NAME: "Management"} {ID: 3 CODE: "SHIPPED" NAME: "Shipped"} Now let's take an example: a user enters a new order. In the case in which use natural keys, in the code I can write this: newOrder.StateOrderId = "NEW"; With the surrogate keys instead every time I have an additional step. stateOrderId_NEW = .... I retrieve the id corresponding to the recod code "NEW" newOrder.StateOrderId = stateOrderId_NEW; The same will happen every time I have to move the order in a new status. So, in this case, what are the reason to chose one key type vs the other one?

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  • DB Design Question

    - by hazimdikenli
    I am designing an Org Chart, model is almost ready and simplified a bit for clarity here. OrgUnit (OrgUnitId, Name, ReportsToOrgUnitId, ...) OrgUnitJobs (OrgUnitJobId, OrgUnitId, JobName, ReportsToOrgUnitJobId, ... ,IsJobGroup) Employee (EmployeeId, ........) OrgUnitJobEmployee (OrgUnitJobId, EmployeeId, AssignedDate, .....,) so I want to know every OrgUnit's ManagerEmployee (should have one), and Employees can have more than one job, but one of them has to be the main job, so I know whats his manager and other stuff. This is going to support a little workflow behind the scnese, so that is why it is not a very simple Org chart Model. so what would you do, would you add properties like (IsManager property to OrgUnitJobs model) or add ManagerOrgUnitJobId to OrgUnitModel. and why? Likewise, for employees would you add IsPrimaryJob property to OrgUnitJobEmployee model, or add PrimaryJobId to Employee Model.

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  • How to detect a pending JDO transaction?

    - by Stevko
    I believe I am getting JDO commit Exceptions due to the transactions nesting although I'm not sure. Will this detect the situation where I am starting a transaction when another is pending? PersistenceManager pm = PersistenceManagerFactory.get().getPersistenceManager(); assert pm.currentTransaction().isActive() == false : "arrrgh"; pm.currentTransaction().begin(); Is there a better or more reliable way?

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