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  • count(*) vs count(row-name) - which is more correct?

    - by bread
    Does it make a difference if you do count(*) vs count(row-name) as in these two examples? I have a tendency to always write count(*) because it seems to fit better in my mind with the notion of it being an aggregate function, if that makes sense. But I'm not sure if it's technically best as I tend to see example code written without the * more often than not. count(*): select customerid, count(*), sum(price) from items_ordered group by customerid having count(*) > 1; vs. count(row-name): SELECT customerid, count(customerid), sum(price) FROM items_ordered GROUP BY customerid HAVING count(customerid) > 1;

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  • form not showing for empty records

    - by Chris Hodges
    I have a relatively simple PHP page called editcustomers with 3 columns. The problem I'm having is that the form will show when there is a record in the database and the fields will be populated with that info. When no such records exists, the form is not even shown, eliminating the possibility to insert a record. My page layout is as follows: Column 1 shows a form containing customer information, allowing it to be edited. Column 2 allows ordering of products and showing how many products were ordered Column 3 shows the total paid so far, and the total owing. The code for the page I have at present: <html> <?php $id = $_GET['id']; require_once('connect.php'); $sth = $dbh->query("SELECT * FROM users where id = '$id';"); $sth->setFetchMode(PDO::FETCH_ASSOC); $eth = $dbh->query("SELECT * FROM purchases where id = '$id';"); $eth->setFetchMode(PDO::FETCH_ASSOC); ?> <div id="main"> <div id="left"> <form name="custInfo" action ="process.php" method ="post" > <input type = "hidden" name ="formType" value="custInfo"/> <?php while($row = $sth->fetch()){ ?> <p><input type = "hidden" name ="id" value="<?php echo $row["id"] ?>"/> <p><input type = "text" name ="firstName" size ="30" value=" <?php echo $row["firstName"]?>"/> <p><input type = "text" name ="lastName" size ="30" value="<?php echo $row["lastName"]?>"/> <p><input type = "text" name ="country" size ="30" value="<?php echo $row["country"]?>"/> <p></p> <input type="submit" value="Update" /> <?php }?> </div> <div id="mid"> <form name="custCosts" action ="process.php" method ="post" > <input type = "hidden" name ="formType" value="custCosts"/> <?php while($row = $eth->fetch()){ ?> <p><input type = "hidden" name ="id" value="<?php echo $row["id"] ?>"/> <p><input type = "text" name ="amountOwed" size ="30" value=" <?php echo $row["amountOwed"]?>"/> <p><input type = "text" name ="numAaa" size ="30" value="<?php echo $row["numAaa"]?>"/> <p><input type = "text" name ="numBbb" size ="30" value="<?php echo $row["numBbb"]?>"/> <p></p> <input type="submit" value="Update" /> <?php }?> </div> <div id="right"> <b>Total Balance</b> <p> Money owed: </p> <p> aaa total: </p> <p> bbb total: </p> <p> Total: </p> <input type = "text" name ="pay" size ="20" /></p> <input type="submit" value="Make Payment" /> </div> <?php $dbh =null; ?> </body> </html> And the code for all the database trickery: <?php require_once 'connect.php'; $formType = $_POST['formType']; $id = $_POST['id']; $firstName = $_POST['firstName']; $lastName = $_POST['lastName']; $country = $_POST['country']; $amountOwed = $_POST['amountOwed ']; $numAaa = $_POST['numAaa']; $numBbb = $_POST['numBbb']; if(empty($_POST['id'])) { $sth = $dbh->prepare("INSERT INTO customers (firstName, lastName, country) VALUES ('$firstName', '$lastName', '$country')"); $sth->execute(); } elseif(!empty($_POST['id']) && !isset($_POST['stayCost']) && $_POST['formType'] == 'guestInfo'){ $sth = $dbh->prepare("UPDATE customers SET firstName = '$firstName', lastName = '$lastName', country = '$country' WHERE id = '$id'"); $sth->execute(); }elseif(!empty($_POST['id']) && isset($_POST['stayCost']) && $_POST['formType'] == 'guestInfo'){ $sth = $dbh->prepare("INSERT INTO purchases (id, amountOwed, numAaa, numBbb) VALUES ('$id', '$amountOwed', '$numAaa', '$numBbb'"); $sth->execute(); }elseif(!empty($_POST['id']) && $_POST['formType'] == 'guestCosts'){ $sth = $dbh->prepare("UPDATE purchases SET amountOwed= '$amountOwed', numAaa = '$numAaa', numBbb= '$numBbb' WHERE id = '$id'"); $sth->execute(); } $dbh =null; ?> Why does the form not even display if there is no record? An error or something I might understand....but the form is still in the HTML and should still be being output, from what I can see. Why is this not the case?

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  • How would I associate a "Note" class to 4+ classes without creating lookup table for each associatio

    - by Gthompson83
    Im creating a project tasklist application. I have project, section, task, issue classes, and would like to use one class to be able to add simple notes to any object instance of those classes. The task, issue tables both use a standard identity field as a primary key. The section table has a two field primary key. The project table has a single int primary key defined by the user. Is there a way to associate the note class with each of these without using a seperate lookup table for each class? I'm not so sure my original idea is a decent way to implement this. I considered the following (each variable mapping to a field n the notes table. Private _NoteId As Integer Private _ProjectId As Integer Private _SectionId As Integer Private _SectionId2 As Integer Private _TaskId As Integer Private _IssueId As Integer Private _Note As String Private _UserId As Guid Then I would be able to write seperate methods (getProjectNotes, getTaskNotes) to get notes attached to each class. I started writing this a few weeks ago but got pulled away before i could finish. When revisiting this code today my first thought "this is retarded". Thoughts on drawbacks to this design?

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  • How to analyse Wikipedia article's data base with R?

    - by Tal Galili
    Hi all, This is a "big" question, that I don't know how to start, so I hope some of you can give me a direction. And if this is not a "good" question, I will close the thread with an apology. I wish to go through the database of Wikipedia (let's say the English one), and do statistics. For example, I am interested in how many active editors (which should be defined) Wikipedia had at each point of time (let's say in the last 2 years). I don't know how to build such a database, how to access it, how to know which types of data it has and so on. So my questions are: What tools do I need for this (besides basic R) ? MySQL on my computer? RODBC database connection? How do you start planning for such a project?

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  • Subquery with multiple results combined into a single field?

    - by Todd
    Assume I have these tables, from which i need to display search results in a browser: Table: Containers id | name 1 Big Box 2 Grocery Bag 3 Envelope 4 Zip Lock Table: Sale id | date | containerid 1 20100101 1 2 20100102 2 3 20091201 3 4 20091115 4 Table: Items id | name | saleid 1 Barbie Doll 1 2 Coin 3 3 Pop-Top 4 4 Barbie Doll 2 5 Coin 4 I need output that looks like this: itemid itemname saleids saledates containerids containertypes 1 Barbie Doll 1,2 20100101,20100102 1,2 Big Box, Grocery Bag 2 Coin 3,4 20091201,20091115 3,4 Envelope, Zip Lock 3 Pop-Top 4 20091115 4 Zip Lock The important part is that each item type only gets one record/row in the return on the screen. I accomplished this in the past by returning multiple rows of the same item and using a scripting language to limit the output. However, this makes the ui overly complicated and loopy. So, I'm hoping I can get the database to spit out only as many records as there are rows to display. This example may be a bit extreme because of the 2 joins needed to get to the container from the item (through the sale table). I'd be happy for just an example query that outputs this: itemid itemname saleids saledates 1 Barbie Doll 1,2 20100101,20100102 2 Coin 3,4 20091201,20091115 3 Pop-Top 4 20091115 I can only return a single result in a subquery, so I'm not sure how to do this.

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  • Can't delete record via the datacontext it was retrieved from

    - by Antilogic
    I just upgraded one of my application's methods to use compiled queries (not sure if this is relevant). Now I'm getting contradicting error messages when I run the code. This is my method: MyClass existing = Queries.MyStaticCompiledQuery(MyRequestScopedDataContext, param1, param2).SingleOrDefault(); if (existing != null) { MyRequestScopedDataContext.MyClasses.DeleteOnSubmit(existing); } When I run it I get this message: Cannot remove an entity that has not been attached. Note that the compiled query and the DeleteOnSubmit reference the same DataContext. Still I figured I'd humor the application and add an attach command before the DeleteOnSubmit, like so: MyClass existing = Queries.MyStaticCompiledQuery(MyRequestScopedDataContext, param1, param2).SingleOrDefault(); if (existing != null) { MyRequestScopedDataContext.MyClasses.Attach(existing); MyRequestScopedDataContext.MyClasses.DeleteOnSubmit(existing); } BUT... When I run this code, I get a completely different contradictory error message: An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported. I'm at a complete loss... Does anyone else have some insight as to why I can't delete a record via the same DataContext I retrieved it from?

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  • Clustered index on frequently changing reference table of one or more foreign keys

    - by Ian
    My specific concern is related to the performance of a clustered index on a reference table that has many rapid inserts and deletes. Table 1 "Collection" collection_pk int (among other fields) Table 2 "Item" item_pk int (among other fields) Reference Table "Collection_Items" collection_pk int, item_pk int (combined primary key) Because the primary key is composed of both pks, a clustered index is created and the data physically ordered in the table according to the combined keys. I have many users creating and deleting collections and adding and removing items to those collections very frequently affecting the "Collection_Items" table, and its clustered index. QUESTION PART: Since the "Collection_Items" table is so dynamic, wouldn't there be a big performance hit on constantly resorting the table rows because of the clustered index ? If yes, what should I do to minimize this ?

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  • How to avoid geometric slowdown with large Linq transactions?

    - by Shaul
    I've written some really nice, funky libraries for use in LinqToSql. (Some day when I have time to think about it I might make it open source... :) ) Anyway, I'm not sure if this is related to my libraries or not, but I've discovered that when I have a large number of changed objects in one transaction, and then call DataContext.GetChangeSet(), things start getting reaalllly slooowwwww. When I break into the code, I find that my program is spinning its wheels doing an awful lot of Equals() comparisons between the objects in the change set. I can't guarantee this is true, but I suspect that if there are n objects in the change set, then the call to GetChangeSet() is causing every object to be compared to every other object for equivalence, i.e. at best (n^2-n)/2 calls to Equals()... Yes, of course I could commit each object separately, but that kinda defeats the purpose of transactions. And in the program I'm writing, I could have a batch job containing 100,000 separate items, that all need to be committed together. Around 5 billion comparisons there. So the question is: (1) is my assessment of the situation correct? Do you get this behavior in pure, textbook LinqToSql, or is this something my libraries are doing? And (2) is there a standard/reasonable workaround so that I can create my batch without making the program geometrically slower with every extra object in the change set?

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  • How efficient is a details table?

    - by Jeffrey Lott
    At my job, we have pseudo-standard of creating one table to hold the "standard" information for an entity, and a second table, named like 'TableNameDetails', which holds optional data elements. On average, for every row in the main table will have about 8-10 detail rows in it. My question is: What kind of performance impacts does this have over adding these details as additional nullable columns on the main table?

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  • Change update value of property (LINQTOSQL)

    - by Dynde
    Hi... I've got an entity object - Customer, with a property called VATRate. This VATRate is in the form of a decimal (0.25). I wanted to be able to enter a percentage value, and save it in the correct decimal value in the database, so I made this custom property: partial class Customer{ public decimal VatPercent { get{ ... //Get code works fine} set { this.VATRate = (value / 100); } } } And then I just bind this property instead of VATRate in my ASPX editTemplate (formview). This actually works - at least one time, when I debug an update, the value is set correctly one time, and then right after it gets set to the old value. I can't really see why it sets the value twice (and with the old value the second time). Can anyone shed some light on this?

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  • mysql reference result from subquery

    - by iamrohitbanga
    this is what i am doing update t1 set x=a,y=b where a and b are obtained from (select query here) i know the select query the select query returns multiple results which are the same when i use group by or distinct query execution slows down considerably a and b are forward references so mysql reports an error i want to set a equal to the value obtained in the first row and b equal to the value obtained in the first row for the respective columns, to avoid group by. i don't know how to refer to the first result from the select query. how can i achieve all this?

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  • Only show certain items in a mysql database using php and time()

    - by Jon
    Is there a way to only show the items that are older than a certain date in a php mysql array? I'm using this query method and sorting by lastpost_cl: $query="SELECT * FROM properties ORDER BY lastpost_cl"; $result=mysql_query($query); $num = mysql_num_rows ($result); mysql_close(); and I was thinking the way of checking the time would be: if (time() <= strtotime($lastpost_cl)) { } How can I combine the two and only show lastpost_cl that are older that the current time?

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  • Should I sanitize EVERY form variable passed along?

    - by Camran
    I have a form with many fields... The action is set to a php page which queries mysql... Should I sanitize with mysql_real_escape_string every single variable? Or can I ignore sanitizing drop-lists and radios for instance? Also, besides mysql_real_escape_string, what else should I do to prevent attacks? Thanks

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  • Change an autoincrementing field to one previous

    - by jlan
    One day, wordpress suddenly jumped from pots id 9110 to 890000000 post. Days later I'd like to move back new posts to continue from id 9111. I'm sure that id will never reach id 890000000, no problem here, but id is an autoincrement field and "ALTER TABLE wp8_posts AUTO_INCREMENT =9111" is not working. Can I force id to continue from 9111 ?

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  • Is count(*) really expensive ?

    - by Anil Namde
    I have a page where I have 4 tabs displaying 4 different reports based off different tables. I obtain the row count of each table using a select count(*) from <table> query and display number of rows available in each table on the tabs. As a result, each page postback causes 5 count(*) queries to be executed (4 to get counts and 1 for pagination) and 1 query for getting the report content. Now my question is: are count(*) queries really expensive -- should I keep the row counts (at least those that are displayed on the tab) in the view state of page instead of querying multiple times? How expensive are COUNT(*) queries ?

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  • How should I build a gaming community

    - by Przystojny
    I've been wanting to build my own gaming community site (like http://fragbite.com) for a long time, I have started many times but just quitted after a couple days because it gets very messy I've been palying around with php and mysql off and on for 3 years but i've never gotten in to oop. i have tried but i usually end up with the "old php". I usually build my pages like so that i include a file on top of all pages with neccasary functions, html head etc. And I mix php and html together which I dont mind but if I eventually would get a designer he would not like it i think. I have tried both phpcake and codeigniter and all those popular mvc's but its just to much, like they do all the work. i want to do it myself. but i dont know where to start. What would you do if you were me? Is there maybe some non-oop mvc? (Sorry for my english)

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  • Classic ASP shopping cart discounts

    - by Neil Bradley
    Hi there, I have a Classic ASP shopping cart, but I need to add in an option to enter a promo code and (if valid) apply a discount to the total. There is a promo codes table that stores the promotional codes and the value of the discount to apply. So I was wondering if someone might be able to help me integrate this? Happy to pay for the time. I think it may only take an hour or so at most. :S

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  • getting complete sql query in jython

    - by kdev
    result=sqlstring.executeQuery("select distinct table_name,owner from all_tables ") rs.append(str(i)+' , '+result.getString("table_name")+' , '+result.getString("owner")) If i want to display the query select * from all_tables or ' select count(*) from all_tables' how can i get the output to display . Please suggest thanks

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  • MySQL: selecting totals as three fields from same table as one query?

    - by coderama
    I have a table with various orders in it: ID | Date | etc... 1 | 2013-01-01 | etc 2 | 2013-02-01 | etc 3 | 2013-03-01 | etc 4 | 2013-04-01 | etc 5 | 2013-05-01 | etc 6 | 2013-06-01 | etc 7 | 2013-06-01 | etc 8 | 2013-03-01 | etc 9 | 2013-04-01 | etc 10 | 2013-05-01 | etc I want a query that ends wit the result: overallTotal | totalThisMonth | totalLastMonth 10 | 2 | 1 But I want to do this in one query! I am trying to find a way to use subqueries to do this. SO far I have: SELECT * from ( SELECT count(*) as overallTotal from ORDERS ) How can I combine this with other subqueries so I can get the totals in one query?

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  • Search field based on multiple parameter

    - by Manoj Wadhwani
    Can anybody modify this , when i insert Emp. name it go to first search and it does not check other paramete could you plz modify this sp for exact search on based on parameter. --select * from Training_TRNS --USP_SearchEmployee '','2008-04-18 00:00:00.000','','','','','' alter Procedure USP_SearchEmployee @EmpName varchar(100)=null, @DateFrom varchar(100)=null, @DateTo varchar(100)=null, @CourseName varchar(100)=null, @JobFunction varchar(100)=null, @Region varchar(100)=null, @Status varchar(100)=null AS BEGIN if (@EmpName!='' and @EmpName is not null) BEGIN select EmpName,convert(varchar,DueDate,101) as DueDate,SpeCourse_ID as CourseName, EmpJobFunction as JOBFunction,EmpRegion as Region,Status from Training_TRNS where EmpName like '%'+@EmpName+'%' END ELSE IF (@CourseName!='' and @CourseName is not null) BEGIN select EmpName,convert(varchar,DueDate,101) as DueDate,SpeCourse_ID as CourseName, EmpJobFunction as JOBFunction,EmpRegion as Region,Status from Training_TRNS where SpeCourse_ID like '%'+@CourseName+'%' END ELSE IF (@JobFunction!='' and @JobFunction is not null) BEGIN select EmpName,convert(varchar,DueDate,101) as DueDate,SpeCourse_ID as CourseName, EmpJobFunction as JOBFunction,EmpRegion as Region,Status from Training_TRNS where EmpJobFunction like '%'+@JobFunction+'%' END ELSE IF (@Region!='' and @Region is not null) BEGIN select EmpName,convert(varchar,DueDate,101) as DueDate,SpeCourse_ID as CourseName, EmpJobFunction as JOBFunction,EmpRegion as Region,Status from Training_TRNS where EmpRegion like '%'+@Region+'%' END ELSE IF (@Status!='' and @Status is not null) BEGIN select EmpName,convert(varchar,DueDate,101) as DueDate,SpeCourse_ID as CourseName, EmpJobFunction as JOBFunction,EmpRegion as Region,Status from Training_TRNS where Status like '%'+@Status+'%' END ELSE IF (@DateFrom!='' and @DateFrom is not null) BEGIN select EmpName,convert(varchar,DueDate,101) as DueDate,SpeCourse_ID as CourseName, EmpJobFunction as JOBFunction,EmpRegion as Region,Status from Training_TRNS where convert(varchar,DueDate,101) like '%'+convert(varchar,@DateFrom,101)+'%' END Else BEGIN select EmpName,convert(varchar,DueDate,101) as DueDate,SpeCourse_ID as CourseName, EmpJobFunction as JOBFunction,EmpRegion as Region,Status from Training_TRNS END END

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  • How can I bind an Enum to a DbType of bit or int?

    - by uriDium
    Hi I am using Linq2Sql and want to bind an objects field (which is enum) to either a bit or a int type in the database. For example I want have a gender field in my model. I have already edited the DBML and changed the Type to point to my enum. I want to create Radio buttons (which I think I have figured out) for gender and dropdown lists for other areas using the same idea. My enum looks like this public enum Gender { Male, Female } Mapping between DbType 'int' and Type 'Project.Models.Gender' in Column 'Gender' of Type 'Candidate' is not supported. Any ideas on how to do this mapping. Am I missing something on the enums.

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