Search Results

Search found 62701 results on 2509 pages for 'sql function'.

Page 792/2509 | < Previous Page | 788 789 790 791 792 793 794 795 796 797 798 799  | Next Page >

• Can I chain database links in Oracle?

  - by RenderIn

  I have 3 databases. 1 links to 2, 2 links to 3. I'd like to query tables in 3, from 1. I tried third_db_tab@3@2 and it did not work. Wondering if this is possible and if so, what the syntax is.

  Read the article

• Postgresql count+sort performance

  - by invictus

  I have built a small inventory system using postgresql and psycopg2. Everything works great, except, when I want to create aggregated summaries/reports of the content, I get really bad performance due to count()'ing and sorting. The DB schema is as follows: CREATE TABLE hosts ( id SERIAL PRIMARY KEY, name VARCHAR(255) ); CREATE TABLE items ( id SERIAL PRIMARY KEY, description TEXT ); CREATE TABLE host_item ( id SERIAL PRIMARY KEY, host INTEGER REFERENCES hosts(id) ON DELETE CASCADE ON UPDATE CASCADE, item INTEGER REFERENCES items(id) ON DELETE CASCADE ON UPDATE CASCADE ); There are some other fields as well, but those are not relevant. I want to extract 2 different reports: - List of all hosts with the number of items per, ordered from highest to lowest count - List of all items with the number of hosts per, ordered from highest to lowest count I have used 2 queries for the purpose: Items with host count: SELECT i.id, i.description, COUNT(hi.id) AS count FROM items AS i LEFT JOIN host_item AS hi ON (i.id=hi.item) GROUP BY i.id ORDER BY count DESC LIMIT 10; Hosts with item count: SELECT h.id, h.name, COUNT(hi.id) AS count FROM hosts AS h LEFT JOIN host_item AS hi ON (h.id=hi.host) GROUP BY h.id ORDER BY count DESC LIMIT 10; Problem is: the queries runs for 5-6 seconds before returning any data. As this is a web based application, 6 seconds are just not acceptable. The database is heavily populated with approximately 50k hosts, 1000 items and 400 000 host/items relations, and will likely increase significantly when (or perhaps if) the application will be used. After playing around, I found that by removing the "ORDER BY count DESC" part, both queries would execute instantly without any delay whatsoever (less than 20ms to finish the queries). Is there any way I can optimize these queries so that I can get the result sorted without the delay? I was trying different indexes, but seeing as the count is computed it is possible to utilize an index for this. I have read that count()'ing in postgresql is slow, but its the sorting that are causing me problems... My current workaround is to run the queries above as an hourly job, putting the result into a new table with an index on the count column for quick lookup. I use Postgresql 9.2.

  Read the article

• Storing users in a database

  - by EMcKenna

  Im wondering whats the best way of storing different types of users in my database. I am writing an application that has 4 main user types (admin, school, teacher, student). At the moment I have a table for each of these but i'm not sure thats the best way of storing user information. For instance... Allowing students to PM other student is simple (store sender and receiver student_id) but enabling teachers to PM students requires another table (sender teacher_id, sender student_id). Should all users be stored in one users table with a user_type field? If so, the teacher / student specific information will still have to be stored in another table. users user_id, password_hash, user_type students user_id, student_specific_stuff... teachers user_id, teacher_specific_stuff... How do I stop a user who has a user_type = student from being accidentally being entered into the teachers table (as both have a user_id) Just want to make sure I get the database correct before i go any further. Thanks...

  Read the article

• How to run an .exe application in another computer?

  - by ADAM

  I am working on a C# application in Visual Studio 2013. When I run the .exe file from my computer, the application runs very well and all the features work. When I tried to run the .exe on another computer, the database side doesn't work well and the connection with the database couldn't be opened. The SqlConnection is constructed as follows: SqlConnection cn = new SqlConnection("Data Source=ADAM-PC;Initial Catalog=integrationdatabase;Integrated Security=True" I don't know how to change the data source to make the connection with the database established in another computer. How can I solve this problem?

  Read the article

• SQLAlchemy & Complex Queries

  - by user356594

  I have to implement ACL for an existing application. So I added the a user, group and groupmembers table to the database. I defined a ManyToMany relationship between user and group via the association table groupmembers. In order to protect some ressources of the app (i..e item) I added a additional association table auth_items which should be used as an association table for the ManyToMany relationship between groups/users and the specific item. item has following columns: user_id -- user table group_id -- group table item_id -- item table at least on of user_id and group_id columns are set. So it's possible to define access for a group or for a user to a specific item. I have used the AssociationProxy to define the relationship between users/groups and items. I now want to display all items which the user has access to and I have a really hard time doing that. Following criteria are used: All items which are owned by the user should be shown (item.owner_id = user.id) All public items should be shown (item.access = public) All items which the user has access to should be shown (auth_item.user_id = user.id) All items which the group of the user has access to should be shown. The first two criteria are quite straightforward, but I have a hard time doing the 3rd one. Here is my approach: clause = and_(item.access == 'public') if user is not None: clause = or_(clause,item.owner == user,item.users.contains(user),item.groups.contains(group for group in user.groups)) The third criteria produces an error. item.groups.contains(group for group in user.groups) I am actually not sure if this is a good approach at all. What is the best approach when filtering manytomany relationships? How I can filter a manytomany relationship based on another list/relationship? Btw I am using the latest sqlalchemy (6.0) and elixir version Thanks for any insights.

  Read the article

• How to generate a transaction number?

  - by 001

  I was thinking of formatting it like this TYYYYMMDDNNNNNNNNNNX (1 character + 19 digits) Where T is type YYYY is year MM is month DD is day N is sequencial number X is check digit The problem is, how do I generate the sequencial number? since my primary key is not an auto increment integer value, if it was i would use that, but its not. EDIT can I have the sequencial number resets itself after 1 day (24hours). P201012080000000001X <-- first transaction of 2010/12/08 P2010120810000000002X <--- second transaction of 2010/12/08 P201012090000000001X <--- First transaction of 2010/12/09 (X is the check digit)

  Read the article

• How Can I Reference Multiple Primary Keys For A Vector Type Primary Key

  - by AndreiC

  Hi, I have the following scenario: a table of projects and a table of persons, working on one or serveral projects. Also, I have a project id column (of type int), in the first table, which is a primary key there and I have a vector of project ids, as a column of type int, in my second table (persons), that references primary keys from the first table. What is the correct syntax for referencing multiple primary keys, from a vector foreign key. This is the way I am trying to create the table, but I am not sure what to place at the indicated line: CREATE TABLE Persons( Person_Id int, ..., ProjectsList int[], FOREIGN KEY (ProjectsList) REFERENCES Projects(Project_id) -- not sure what how to define the link here ); I hope my explanations are not over-complicated. Thank you in advance for helping!

  Read the article

• What is wrong with this connection string?

  - by Hakan

  Can any one help me with this connection string. I can't manage how to fix. Dim constring As String Dim con As SqlCeConnection Dim cmd As SqlCeCommand constring = "(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase) + \\database.sdf;Password=pswrd;File Mode=shared read" con = New SqlCeConnection() con.Open() Thanks

  Read the article

• PostgreSQL - select only when specific multiple apperance in column

  - by Horse SMith

  I'm using PostgreSQL. I have a table with 3 fields person, recipe and ingredient person = creator of the recipe recipe = the recipe ingredient = one of the ingredients in the recipe I want to create a query which results in every person who whenever has added carrot to a recipe, the person must also have added salt to the same recipe. More than one person can have created the recipe, in which case the person who added the ingredient will be credited for adding the ingredient. Sometimes the ingredient is used more than once, even by the same person. If this the table: person1, rec1, carrot person1, rec1, salt person1, rec1, salt person1, rec2, salt person1, rec2, pepper person2, rec1, carrot person2, rec1, salt person2, rec2, carrot person2, rec2, pepper person3, rec1, sugar person3, rec1, carrot Then I want this result: person1 Because this person is the only one who whenever has added carrot also have added salt.

  Read the article

• select from varchar2 column with numeric value sometimes gives invalid number error

  - by Rene

  I'm trying to understand why, on some systems, I get an invalid number error message when I'm trying to select a value from a varchar2 column while on other systems I don't get the error while doing the exact same thing. The table is something like this: ID Column_1 Column_2 1 V text 2 D 1 3 D 2 4 D 3 and a query: select ID from table where column_1='D' and column_2 = :some_number_value :some_number_value is always numeric but can be null. We've fixed the query: select ID from table where column_1='D' and column_2 = to_char(:some_number_value) This original query runs fine on most systems but on some systems gives an "invalid number" error. The question is why? Why does it work on most systems and not on some?

  Read the article

• Linq2SQL InfoMessage

  - by Paul Oakham

  Hi, is it possible to access the InfoMessage event handler in a Linq2SQL data context? All of our code uses these messages to display useful information to the end user and since moving to Linq2SQL I cannot figure out how to show these messages. I have checked the connection object of the data context as well as the classes properties with no luck so I'm wondering if it is possible. Thanks in advance.

  Read the article

• SqlCE DB occasionally freezes on one handheld, not another

  - by Michael

  I have two types of custom handhelds which are similar, but slightly different, each running the same WinForm application and a WinCE database: Type 1: WinCE 4.2, 400 mhz, 93244 kb Type 2: WinCE 5.0, 520 mhz, 84208 kb Type 1 will happily proceed through a large batch db operation (initiated) by the app, by Type 2 will consistently begin c-r-a-w-l-i-n-g (for several to many cycles) at around the 200 cycle mark. As several points it will begin running normally and then crawl again. The app does several db op's (inserts, updates and selects, no deletes). To simplify my situation, I've built a small test app which essentially does this: command_s.CommandText = "select dvr from vr where vid = 2211250"; command_u.CommandText = "update pvr set LocationID=81 where Status='OK' and vri = 27861"; while(going) { command_s.ExecuteScalar(); command_u.ExecuteNonQuery(); } and set it off running on the two units side by side. Sure enough, the slower (400 mhz) unit is outpacing the faster (520 mhz) unit (it's about 5000 cycles ahead right now) and I can see noticable pauses on the 520 mhz unit. What is causing this?

  Read the article

• Linq Distinct() by name for populate a dropdown list with name and value

  - by AndreMiranda

  I'm trying to populate a Drop down list with pharmaceutical companies, like Bayer, Medley etc. And, I'm getting theses names from DB and theses names are repeated in DB, but with different id's. I'm trying to use Linq Distinct(), but I don't want to use the equality comparer. Is there another way? My drop down list must be filled with the id and the name of the company. I'm trying something like: var x = _partnerService .SelectPartners() .Select(c => new {codPartner = c.codPartner, name = c.name}) .Distinct(); This is showing repeated companies in ddl. thanks!

  Read the article

• HTML5 Web Database Security

  - by Daniel Dimovski

  Should the HTML5 database be used to store any form of private information? Say we have the following scenario; You're browsing a web-mail client, that uses the web database to store mail drafts after you've written some information you close the web browser. What's to stop me from getting access to this information? If the webpage tries to clean out old information when opened a user-script could easily prevent the website from fully loading and then search through the database. Furthermore the names of databases and tables are easily available through the web-mail client's source. W3C Draft

  Read the article

• What is the difference between these two LINQ statements?

  - by jamone

  I had the 1nd statement in my code and found it not giving an accurate count, it was returning 1 when the correct answer is 18. To try and debug the problem I broke it out creating the 2nd statement here and the count returns 18. I just don't see what the difference is between these two. It seems like the 1st is just more compact. I'm currently running these two statements back to back and I'm sure that the database isn't changing between the two. int count = (from s in surveysThisQuarter where s.FacilityID == facility.LocationID select s.Deficiencies).Count(); vs var tempSurveys = from s in surveysThisQuarter where s.FacilityID == facility.LocationID select s; int count = 0; foreach (Survey s in tempSurveys) count += s.Deficiencies.Count();

  Read the article

• what type of errors can we handle using system define unnamed exception in sqlplus?

  - by Aspirant

  I have been trying to access the below code DECLARE N_DEPTNO DEPT.DEPTNO %TYPE :=&DEPT_NUM; V_DNAME DEPT.DNAME %TYPE; NOT_ENOUGH_VALUES EXCEPTION; PRAGMA EXCEPTION_INIT(NOT_ENOUGH_VALUES,-06502); BEGIN SELECT DNAME,LOC INTO DNAME FROM DEPT WHERE DEPTNO = N_DEPTNO; DBMS_OUTPUT.PUT_LINE('Successfully Fetched !!'); EXCEPTION WHEN NOT_ENOUGH_VALUES THEN DBMS_OUTPUT.PUT_LINE('No Enough Values ... '); END; It is still showing error message after specified it in EXCEPTION block. Can i handle these type of errors using PRAGMA EXCEPTION_INIT i.e not providing enough values in the select statement... If not what type of errors can be handled in System Defined Unnamed Exception using PRAGMA EXCEPTION_INIT.

  Read the article

• How to combine a list of choices to determine which select statement

  - by Larry

  I have a mysql db and am using php 5.2 What I am trying to do is offer a list of options for a person to select (only 1). The chosen option will cause a select, update, or delete statement to be ran. The results of the statement do not need to be shown, although, showing the old and then the new would be nice (no problems with that part tho'.). Pseudo-Code: Assign $choice = 0 Check the value of $choice // This way, if it = 100, we do a break Select a Choice:<br> 1. Adjust Status Value (+60) // $choice = 1<br> 2. Show all Ships <br> // $choice = 2 3. Show Ships in Port <br> // $choice = 3 ... 0. $choice="100" // if the value =100, quit this part Use either case (switch) or if/else statements to run the users choice1 If the choice is 1, then run the "Select" statement with the variable of $sql1 -- "SELECT .... If the choice is 2, then run the "Select" statement with the variable of $sql2 --- SELECT * FROM Ships If the choice is 3, then run the "Select" statement with the variable of $sql3 <br> .... If the choice is 0, then we are done. I figured the (3) statements would be assigned in php as: $sql1="...". $sql2="SELECT * FROM Ships" $sql3="SELECT * FROM Ships WHERE nPort="1" My idea was to use the switch statement, but got lost on it. :( I would like the options to be available over and over again, until a variable ($choice) is selected. In which case, this particular page is done and goes back to the "Main Menu"? The coding and display, if I use it, I can do. Just not sure how to write the way to select which one I want. It is possible that I would run all of the queries, and other times, only one, so that is why I would like the choice. An area I get confused in is the proper forms to use such as -- ' ' " " and ...?? Not sure the # of options I will end up with, but it will be more than 5 but less than 20 / page. So if I get the system down for 2-3 choices, I can replicate it for as many as I may need. And, as always, if a better way exists, I am willing to try it. Thanks again... Larry

  Read the article

• count(*) is it really expensive ?

  - by Anil Namde

  I have a page where i have 4 tabs displaying 4 different reports based of different tables. Now i get row count of each tabled using select count() from table query and display number of rows available in each table on the tabs. Now with each page post back 5 count() queries are executed (4 to get counts and 1 for pagination) and 1 query for getting report. Now my question is should is count(*) query really expensive that i should keep the row counts (at least which are displayed on tab) in view state of page instead of queering each time? How much expensive it is ?

  Read the article

• How perform USort() on an Array of Objects class definition as a method?

  - by user558724

  class Contact{ public $name; public $bgcolor; public $lgcolor; public $email; public $element; public function __construct($name, $bgcolor, $lgcolor, $email, $element) { $this->name = $name; $this->bgcolor = $bgcolor; $this->lgcolor = $lgcolor; $this->email = $email; $this->element = $element; } public static function sortByName(Contact $p1, Contact $p2) { return strcmp($p1->name, $p2->name); } } class ContactList implements Iterator, ArrayAccess { protected $_label; protected $_contacts = array(); public function __construct($label) { $this->_label = $label; } public function getLabel() { return $this->_label; } public function addContact(Contact $contact) { $this->_contacts[] = $contact; } public function current() { return current($this->_contacts); } public function key() { return key($this->_contacts); } public function next() { return next($this->_contacts); } public function rewind() { return reset($this->_contacts); } public function valid() { return current($this->_contacts); } public function offsetGet($offset) { return $this->_contacts[$offset]; } public function offsetSet($offset, $data) { if (!$data instanceof Contact) throw new InvalidArgumentException('Only Contact objects allowed in a ContactList'); if ($offset == '') { $this->_contacts[] = $data; } else { $this->_contacts[$offset] = $data; } } public function offsetUnset($offset) { unset($this->_contacts[$offset]); } public function offsetExists($offset) { return isset($this->_contacts[$offset]); } public function sort($attribute = 'name') { $sortFct = 'sortBy' . ucfirst(strtolower($attribute)); if (!in_array($sortFct, get_class_methods('Contact'))) { throw new Exception('contact->sort(): Can\'t sort by ' . $attribute); } usort($this->contact, 'ContactList::' . $sortFct); } } public function Sort($property, $asc=true) { // this is where sorting logic takes place $_pd = $this->_contact->getProperty($property); if ($_pd == null) { user_error('Property '.$property.' does not exist in class '.$this->_contact->getName(), E_WARNING); return; } // set sortDescriptor ContactList::$sortProperty = $_pd; // and apply sorting usort($this->_array, array('ContactList', ($asc?'USortAsc':'USortDesc'))); } function getItems(){ return $this->_array; } class SortableItem extends ContactList { static public $sortProperty; static function USortAsc($a, $b) { /*@var $_pd ReflectionProperty*/ /* $_pd = self::$sortProperty; if ($_pd !== null) { if ($_pd->getValue($a) === $_pd->getValue($b)) return 0; else return (($_pd->getValue($a) < $_pd->getValue($b))?-1:1); } return 0; } static function USortDesc($a, $b) { return -(self::USortAsc($a,$b)); } } This approach keeps giving me PHP Warnings: usort() [function.usort]: of all kinds which I can provide later as needed to comment out those methods and definitions in order to test and fix some minor bugs of our program. **$billy parameters are already defined. $all -> addContact($billy); // --> ended up adding each contact manually above $all->Sort('name',true); $items = $all->getItems(); foreach($items as $contact) { echo $contact->__toString(); } $all->sort(); The reason for using usort is to re-arrange the order alphabetically by name but somehow is either stating that the function comparison needs to be an array or another errors which obviously I have seemed to pass. Any help would be greatly appreciated, thanks in advance.

  Read the article

• I want to run two or more procedures in parallel

  - by binod gyawali

  I have list of procedures. All procedures are not dependent upon each other. So, I need to do is, to run the independent procedures in parallel. I have 4 procedures that are to be run parallel. When the procedures are run successfully, now I need to go to the next task. These procedures create about 10 tables. Next task is to execute the set of procedures. I have made one table, where I describe the dependency of these procedures to the tables created above. After any one of the above procedures is completed, I should come to this set of procedures, and find out those procedures whose dependency tables are already created. If any procedure whose dependent tables creation is completed, I need to execute this procedure. Running 4 procedures parallel is done by dts. But, difficulty for me is to transfer the task from the above 4 procedures to the below set of procedures. Please help me to complete my task. Thanks in advance

  Read the article

• How can I disable a button in a JQuery dialog from a function?

  - by Draco

  Hi, I have a JQuery dialog that requires the user to enter certain information. In this form I have a "continue" button. I would like this "continue" button to only be enabled once all the fields have content in them else it will remain disabled. I wrote a function that is called everytime a field status has changed however I don't know how to enable and disable the dialog button from this function. Any ideas? Oops and I forgot to mention that these buttons were created as follows: $(function() { $("#dialog").dialog({ bgiframe: true, height: 'auto', width: 700, show: 'clip', hide: 'clip', modal: true, buttons: { 'Add to request list': function() { $(this).dialog('close'); $('form').submit(); }, 'Cancel': function() { $(this).dialog('close'); } } });

  Read the article

• Delete query in Linq

  - by Ani

  I have this simple code but it shows error. I dont know where I am going wrong. I shows error in last line.."DeleteOnSubmit" linq_testDataContext db = new linq_testDataContext(); var remove = from aremove in db.logins where aremove.username == userNameString && aremove.Password == pwdString select aremove; db.logins.DeleteOnSubmit(remove); Thanks, Ani

  Read the article

• validate linqtosql mapping to a model

  - by Coppermill

  I have generated a LinqtoSQL mapping xml file, which I have a valid XSD schema that I check to make sure the XML is correct. Now I want to check that the field type match the Model/Interface for example: checking that the nullable fields are nullable that int are int etc anyone got any ideas if I can do this?

  Read the article

• What would you do to make this code more "over-engineered"? [closed]

  - by Mez

  A friend and I got bored, and, long story short, decided to make an over-engineered FizzBuzz in PHP <?php interface INumber { public function go(); public function setNumber($i); } class FBNumber implements INumber { private $value; private $fizz; private $buzz; public function __construct($fizz = 3 , $buzz = 5) { $this->setFizz($fizz); $this->setBuzz($buzz); } public function setNumber($i) { if(is_int($i)) { $this->value = $i; } } private function setFizz($i) { if(is_int($i)) { $this->fizz = $i; } } private function setBuzz($i) { if(is_int($i)) { $this->buzz = $i; } } private function isFizz() { return ($this->value % $this->fizz == 0); } private function isBuzz() { return ($this->value % $this->buzz == 0); } private function isNeither() { return (!$this->isBuzz() AND !$this->isFizz()); } private function isFizzBuzz() { return ($this->isFizz() OR $this->isBuzz()); } private function fizz() { if ($this->isFizz()) { return "Fizz"; } } private function buzz() { if ($this->isBuzz()) { return "Buzz"; } } private function number() { if ($this->isNeither()) { return $this->value; } } public function go() { return $this->fizz() . $this->buzz() . $this->number(); } } class FizzBuzz { private $limit; private $number_class; private $numbers = array(); function __construct(INumber $number_class, $limit = 100) { $this->number_class = $number_class; $this->limit = $limit; } private function collectNumbers() { for ($i=1; $i <= $this->limit; $i++) { $n = clone($this->number_class); $n->setNumber($i); $this->numbers[$i] = $n->go(); unset($n); } } private function printNumbers() { $return = ''; foreach($this->numbers as $number){ $return .= $number . "\n"; } return $return; } public function go() { $this->collectNumbers(); return $this->printNumbers(); } } $fb = new FizzBuzz(new FBNumber()); echo $fb->go(); In theory, what could we/would you do to make it even more "over-engineered"?

  Read the article

• Where to store site settings: DB? XML? CONFIG? CLASS FILES?

  - by Emin

  I am re-building a news portal of which already have a large number of visits every day. One of the major concerns when re-building this site was to maximize performance and speed. Having said this, we have done many things from caching, to all sort of other measures to ensure speed. Now towards the end of the project, I am having a dilemma of where to store my site settings that would least affect performance. The site settings will include things such as: Domain, DefaultImgPath, Google Analytics code, default emails of editors as well as more dynamic design/display feature settings such as the background color of specific DIVs and default color for links etc.. As far as I know, I have 4 choices in storing all these info. Database: Storing general settings in the DB and caching them may be a solution however, I want to limit the access to the database for only necessary and essential functions of the project which generally are insert/update/delete news items, author articles etc.. XML: I can store these settings in an XML file but I have not done this sort of thing before so I don't know what kind of problems -if any- I might face in the future. CONFIG: I can also store these settings in web.config CLASS FILE: I can hard code all these settings in a SiteSettings class, but since the site admin himself will be able to edit these settings, It may not be the best solution. Currently, I am more close to choosing web.config but letting people fiddle with it too often is something I do not want. E.g. if somehow, I miss out a validation for something and it breaks the web.config, the whole site will go down. My concern basically is that, I cannot forsee any possible consequences of using any of the methods above (or is there any other?), I was hoping to get this question over to more experienced people out here who hopefully help make my decision.

  Read the article

< Previous Page | 788 789 790 791 792 793 794 795 796 797 798 799  | Next Page >