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  • What's the best way to store sort order in SQL?

    - by Duracell
    The guys at the top want sort order to be customizable in our app. So I have a table that effectively defines the data type. What is the best way to store our sort order. If I just created a new column called 'Order' or something, every time I updated the order of one row I imagine I would have to update the order of every row to ensure posterity. Is there a better way to do it?

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  • MySql Query lag time / deadlock?

    - by Click Upvote
    When there are multiple PHP scripts running in parallel, each making an UPDATE query to the same record in the same table repeatedly, is it possible for there to be a 'lag time' before the table is updated with each query? I have basically 5-6 instances of a PHP script running in parallel, having been launched via cron. Each script gets all the records in the items table, and then loops through them and processes them. However, to avoid processing the same item more than once, I store the id of the last item being processed in a seperate table. So this is how my code works: function getCurrentItem() { $sql = "SELECT currentItemId from settings"; $result = $this->db->query($sql); return $result->get('currentItemId'); } function setCurrentItem($id) { $sql = "UPDATE settings SET currentItemId='$id'"; $this->db->query($sql); } $currentItem = $this->getCurrentItem(); $sql = "SELECT * FROM items WHERE status='pending' AND id > $currentItem'"; $result = $this->db->query($sql); $items = $result->getAll(); foreach ($items as $i) { //Check if $i has been processed by a different instance of the script, and if so, //leave it untouched. if ($this->getCurrentItem() > $i->id) continue; $this->setCurrentItem($i->id); // Process the item here } But despite of all the precautions, most items are being processed more than once. Which makes me think that there is some lag time between the update queries being run by the PHP script, and when the database actually updates the record. Is it true? And if so, what other mechanism should I use to ensure that the PHP scripts always get only the latest currentItemId even when there are multiple scripts running in parrallel? Would using a text file instead of the db help?

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  • can I see all SQL statements sent over an ODBC connection?

    - by Dave Cameron
    I'm working with a third-party application that uses ODBC to connect to, and alter, a database. During certain failure modes, the end-results are not what I expect. To understand it better, I'd like some way of inspecting all the statements sent to the database. Is there a way to do this with ODBC? I know with JDBC I could use http://www.p6spy.com/ to see all statements sent, for example when debugging hibernate. p6spy is a "proxy" driver that records commands sent and forwards them on to the real JDBC driver. Another possibility might be a protocol sniffer that would capture statements over the wire. Although, I'm unsure if ODBC includes a standard wire protocol, or only specifieds the API. Does anyone know of existing tools that would allow me to do either of these things? Alternatively, is there another approach I could take?

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  • doubleton pattern in C++

    - by benjamin button
    I am aware of the singleton pattern in C++. but what is the logic to get two instances of the object? is there any such pattern where we could easily get 2 pattern. for the logic i could think of is that i can change the singleton pattern itself to have two objects created inside the class.this works. but if the requirement grows like if i need only 3 or only 4 what is the deswign pattern that i could think of to qualify such requirement?

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  • About can't export the performance problems.

    - by kyrathy
    At first,let me describe my environment My VirtualCenter is install on window 2008 ,and theDataBase that VC used is SQL 2008 I really want to ask is ..... When I use vsphere clinet to connect VC.....I got a problem. the performance chart only can show "realtime "...... whatever I only want to view the chart , or I want to export the performance log . when i manually want to export performance, and I select the time to 1 hour ,1 day ,1 month, or from a to b. it showed "No performance data to report for selected objects" only select realtime can export data normally. Before I install Vsphere 4 , I install the SQL 2008 , used the schema in the install CD(I follow the step to create SQL DB for vSphere) Could anybody help me how to solve this problem? And if need any information ,just tell me to provide. Thanks a lot.

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  • How do you transfer data from SQL Server to db4o?

    - by dde
    I came across this question after searching for a ODBC or JDBC. To my surprise, since I am new to db4o I found there are tools to browse db4o, including a Netbeans and Eclipse plug in. However, when it comes to the question at hand, I only found one company, and the product is not being sold nor demoed (makes me think is not ready yet). So, how do you transfer data? Is there a tool or script I have not found yet?

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  • How can I work around SQL Server - Inline Table Value Function execution plan variation based on par

    - by Ovidiu Pacurar
    Here is the situation: I have a table value function with a datetime parameter ,lest's say tdf(p_date) , that filters about two million rows selecting those with column date smaller than p_date and computes some aggregate values on other columns. It works great but if p_date is a custom scalar value function (returning the end of day in my case) the execution plan is altered an the query goes from 1 sec to 1 minute execution time. A proof of concept table - 1K products, 2M rows: CREATE TABLE [dbo].[POC]( [Date] [datetime] NOT NULL, [idProduct] [int] NOT NULL, [Quantity] [int] NOT NULL ) ON [PRIMARY] The inline table value function: CREATE FUNCTION tdf (@p_date datetime) RETURNS TABLE AS RETURN ( SELECT idProduct, SUM(Quantity) AS TotalQuantity, max(Date) as LastDate FROM POC WHERE (Date < @p_date) GROUP BY idProduct ) The scalar value function: CREATE FUNCTION [dbo].[EndOfDay] (@date datetime) RETURNS datetime AS BEGIN DECLARE @res datetime SET @res=dateadd(second, -1, dateadd(day, 1, dateadd(ms, -datepart(ms, @date), dateadd(ss, -datepart(ss, @date), dateadd(mi,- datepart(mi,@date), dateadd(hh, -datepart(hh, @date), @date)))))) RETURN @res END Query 1 - Working great SELECT * FROM [dbo].[tdf] (getdate()) The end of execution plan: Stream Aggregate Cost 13% <--- Clustered Index Scan Cost 86% Query 2 - Not so great SELECT * FROM [dbo].[tdf] (dbo.EndOfDay(getdate())) The end of execution plan: Stream Aggregate Cost 4% <--- Filter Cost 12% <--- Clustered Index Scan Cost 86%

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  • SQL: select random row from table where the ID of the row isn't in another table?

    - by johnrl
    I've been looking at fast ways to select a random row from a table and have found the following site: http://74.125.77.132/search?q=cache:http://jan.kneschke.de/projects/mysql/order-by-rand/&hl=en&strip=1 What I want to do is to select a random url from my table 'urls' that I DON'T have in my other table 'urlinfo'.The query I am using now selects a random url from 'urls' but I need it modified to only return a random url that is NOT in the 'urlinfo' table. Heres the query: SELECT url FROM urls JOIN (SELECT CEIL(RAND() * (SELECT MAX(urlid) FROM urls ) ) AS urlid ) AS r2 USING(urlid); And the two tables: CREATE TABLE urls ( urlid INT NOT NULL AUTO_INCREMENT PRIMARY KEY, url VARCHAR(255) NOT NULL, ) ENGINE=INNODB; CREATE TABLE urlinfo ( urlid INT NOT NULL PRIMARY KEY, urlinfo VARCHAR(10000), FOREIGN KEY (urlid) REFERENCES urls (urlid) ) ENGINE=INNODB;

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  • removing duplicate strings from a massive array in java efficiently?

    - by Preator Darmatheon
    I'm considering the best possible way to remove duplicates from an (Unsorted) array of strings - the array contains millions or tens of millions of stringz..The array is already prepopulated so the optimization goal is only on removing dups and not preventing dups from initially populating!! I was thinking along the lines of doing a sort and then binary search to get a log(n) search instead of n (linear) search. This would give me nlogn + n searches which althout is better than an unsorted (n^2) search = but this still seems slow. (Was also considering along the lines of hashing but not sure about the throughput) Please help! Looking for an efficient solution that addresses both speed and memory since there are millions of strings involved without using Collections API!

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  • SQL Reporting Services: Why does my report shrink when it's emailed?

    - by Josh Yeager
    I created a simple report and uploaded it to my report server. It looks correct on the report server, but when I set up an email subscription, the report is much narrower than it is supposed to be. Here is what the report looks like in the designer. It looks similar when I view it on the report server: [http://img58.imageshack.us/img58/4893/designqj3.png] Here is what the email looks like: [http://img58.imageshack.us/img58/9297/emailmy8.png] Does anyone know why this is happening?

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  • Generate 10-digit number using a phone keypad

    - by srikfreak
    Given a phone keypad as shown below: 1 2 3 4 5 6 7 8 9 0 How many different 10-digit numbers can be formed starting from 1? The constraint is that the movement from 1 digit to the next is similar to the movement of the Knight in a chess game. For eg. if we are at 1 then the next digit can be either 6 or 8 if we are at 6 then the next digit can be 1, 7 or 0. Repetition of digits are allowed - 1616161616 is a valid number. Is there a polynomial time algorithm which solves this problem? The problem requires us to just give the count of 10-digit numbers and not necessarily list the numbers.

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  • T-SQL - Left Outer Joins - Fileters in the where clause versus the on clause.

    - by Greg Potter
    I am trying to compare two tables to find rows in each table that is not in the other. Table 1 has a groupby column to create 2 sets of data within table one. groupby number ----------- ----------- 1 1 1 2 2 1 2 2 2 4 Table 2 has only one column. number ----------- 1 3 4 So Table 1 has the values 1,2,4 in group 2 and Table 2 has the values 1,3,4. I expect the following result when joining for Group 2: `Table 1 LEFT OUTER Join Table 2` T1_Groupby T1_Number T2_Number ----------- ----------- ----------- 2 2 NULL `Table 2 LEFT OUTER Join Table 1` T1_Groupby T1_Number T2_Number ----------- ----------- ----------- NULL NULL 3 The only way I can get this to work is if I put a where clause for the first join: PRINT 'Table 1 LEFT OUTER Join Table 2, with WHERE clause' select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table1 LEFT OUTER join table2 --****************************** on table1.number = table2.number --****************************** WHERE table1.groupby = 2 AND table2.number IS NULL and a filter in the ON for the second: PRINT 'Table 2 LEFT OUTER Join Table 1, with ON clause' select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table2 LEFT OUTER join table1 --****************************** on table2.number = table1.number AND table1.groupby = 2 --****************************** WHERE table1.number IS NULL Can anyone come up with a way of not using the filter in the on clause but in the where clause? The context of this is I have a staging area in a database and I want to identify new records and records that have been deleted. The groupby field is the equivalent of a batchid for an extract and I am comparing the latest extract in a temp table to a the batch from yesterday stored in a partioneds table, which also has all the previously extracted batches as well. Code to create table 1 and 2: create table table1 (number int, groupby int) create table table2 (number int) insert into table1 (number, groupby) values (1, 1) insert into table1 (number, groupby) values (2, 1) insert into table1 (number, groupby) values (1, 2) insert into table2 (number) values (1) insert into table1 (number, groupby) values (2, 2) insert into table2 (number) values (3) insert into table1 (number, groupby) values (4, 2) insert into table2 (number) values (4)

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  • In SQL / MySQL, can a Left Outer Join be used to find out the duplicates when there is no Primary ID

    - by Jian Lin
    I would like to try using Outer Join to find out duplicates in a table: If a table has Primary Index ID, then the following outer join can find out the duplicate names: mysql> select * from gifts; +--------+------------+-----------------+---------------------+ | giftID | name | filename | effectiveTime | +--------+------------+-----------------+---------------------+ | 2 | teddy bear | bear.jpg | 2010-04-24 04:36:03 | | 3 | coffee | coffee123.jpg | 2010-04-24 05:10:43 | | 6 | beer | beer_glass.png | 2010-04-24 05:18:12 | | 10 | heart | heart_shape.jpg | 2010-04-24 05:11:29 | | 11 | ice tea | icetea.jpg | 2010-04-24 05:19:53 | | 12 | cash | cash.png | 2010-04-24 05:27:44 | | 13 | chocolate | choco.jpg | 2010-04-25 04:04:31 | | 14 | coffee | latte.jpg | 2010-04-27 05:49:52 | | 15 | coffee | espresso.jpg | 2010-04-27 06:03:03 | +--------+------------+-----------------+---------------------+ 9 rows in set (0.00 sec) mysql> select * from gifts g1 LEFT JOIN (select * from gifts group by name) g2 on g1.giftID = g2.giftID where g2.giftID IS NULL; +--------+--------+--------------+---------------------+--------+------+----------+---------------+ | giftID | name | filename | effectiveTime | giftID | name | filename | effectiveTime | +--------+--------+--------------+---------------------+--------+------+----------+---------------+ | 14 | coffee | latte.jpg | 2010-04-27 05:49:52 | NULL | NULL | NULL | NULL | | 15 | coffee | espresso.jpg | 2010-04-27 06:03:03 | NULL | NULL | NULL | NULL | +--------+--------+--------------+---------------------+--------+------+----------+---------------+ 2 rows in set (0.00 sec) But what if the table doesn't have a Primary Index ID, then can an outer join still be used to find out duplicates?

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  • SQL Server 2005. Full Text Search. Need Thesaurus working with NEAR/AND/OR keywords

    - by user305924
    Hi, does anyone know if it's possible to do a thesaurus search together with NEAR or AND/OR keywords. Here is an example of the type of query I want to run: SELECT Title, RANK FROM Item INNER JOIN CONTAINSTABLE(Item, Title, 'FORMSOF(Thesaurus, "red" NEAR "wine")') AS KEY_TBL ON Item.ItemID = KEY_TBL.[KEY] ORDER BY RANK DESC ....But I get the error message: Syntax error near 'NEAR' in the full-text search condition 'FORMSOF(Thesaurus, "red" NEAR "wine")'.

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  • Where do you download a package with java.exe?

    - by Derek
    I was trying to run this java ee program with session beans which involves the 'ant' command apparently and when I try to run 'ant' it says... '"java.exe"' is not recognized as an internal or external command. Soooo I am thinking I need to get java.exe in order to use 'ant' properly. Where can I find it? What downloadable contains it?

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  • Please help debug this ASP.Net [VB] code. Trying to write to text file from SQL Server DB.

    - by NJTechGuy
    I am a PHP programmer. I have no .Net coding experience (last seen it 4 years ago). Not interested in code-behind model since this is a quick temporary hack. What I am trying to do is generate an output.txt file whenever the user submits new data. So an output.txt file if exists should be replaced with the new one. I want to write data in this format : 123|Java Programmer|2010-01-01|2010-02-03 124|VB Programmer|2010-01-01|2010-02-03 125|.Net Programmer|2010-01-01|2010-02-03 I don't know VB, so not sure about string manipulations. Hope a kind soul can help me with this. I will be grateful to you. Thank you :) <%@ Import Namespace="System.IO" %> <%@ Import Namespace="System.Data" %> <%@ Import Namespace="System.Data.SqlClient" %> <script language="vb" runat="server"> sub Page_Load(sender as Object, e as EventArgs) Dim sqlConn As New SqlConnection("Data Source=winsqlus04.1and1.com;Initial Catalog=db28765269;User Id=dbo2765469;Password=ByhgstfH;") Dim myCommand As SqlCommand Dim dr As SqlDataReader Dim FILENAME as String = Server.MapPath("Output4.txt") Dim objStreamWriter as StreamWriter ' If Len(Dir$(FILENAME)) > 0 Then Kill(FILENAME) objStreamWriter = File.AppendText(FILENAME) Try sqlConn.Open() 'opening the connection myCommand = New SqlCommand("SELECT id, title, CONVERT(varchar(10), expirydate, 120) AS [expirydate],CONVERT(varchar(10), creationdate, 120) AS [createdate] from tblContact where flag = 0 AND ACTIVE = 1", sqlConn) 'executing the command and assigning it to connection dr = myCommand.ExecuteReader() While dr.Read() objStreamWriter.WriteLine("JobID: " & dr(0).ToString()) objStreamWriter.WriteLine("JobID: " & dr(2).ToString()) objStreamWriter.WriteLine("JobID: " & dr(3).ToString()) End While dr.Close() sqlConn.Close() Catch x As Exception End Try objStreamWriter.Close() Dim objStreamReader as StreamReader objStreamReader = File.OpenText(FILENAME) Dim contents as String = objStreamReader.ReadToEnd() lblNicerOutput.Text = contents.Replace(vbCrLf, "<br>") objStreamReader.Close() end sub </script> <asp:label runat="server" id="lblNicerOutput" Font-Name="Verdana" />

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  • In SQL, what's the difference between count(column) and count(*)?

    - by Bill the Lizard
    I have the following query: select column_name, count(column_name) from table group by column_name having count(column_name) > 1; What would be the difference if I replaced all calls to count(column_name) to count(*)? This question was inspired by a previous one. Edit: To clarify the accepted answer (and maybe my question), using count(*) in this case returns an extra row in the result that contains a null and the count of null values in the column.

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  • Why did you pick your current job?

    - by Nathan Feger
    Why are you working where you are right now? Specifically, how did you go from offer to acceptance? I have found that it is pretty difficult to figure out how to analyze a new company and I'm looking for some advice. My current choice was heavily influenced by a former mentor of mine. Yet, I'll probably need to be my own man soon enough... So, what did it for you?

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  • Can i lock a record from a join sql statment using ROWLOCK,UPDLOCK ?

    - by Andrea.Ko
    I have a store procedure to get the data i want: SELECT a.SONum, a.Seq1, a.SptNum, a.Qty1, a.SalUniPriP, a.PayNum, a.InvNum, a.BLNum, c.ETD, c.ShpNum, f.IssBan FROM OrdD a JOIN OrdH b ON a.SONum = b.SONum LEFT JOIN Invh c ON a.InvNum = c.InvNum LEFT JOIN cus d ON b.CusCod = d.CusCod LEFT JOIN BL e ON a.BLNum = e.BLNum LEFT JOIN PayMasH f ON f.PayNum = a.PayNum LEFT JOIN Shipment g ON g.ShpNum = c.ShpNum WHERE b.CusCod IN (SELECT CusCod FROM UsrInc WHERE UseID=@UserID and UseLev=@UserLvl) AND d.CusGrp = @CusGrp After i get those records into cursor, i used RowLock, UpdLock to lock all the related invoice number. SELECT InvNum FROM Invh WITH (ROWLOCK,UPDLOCK) WHERE InvNum = Can i issue locking on the table INVH at the point i select the table from a few table using join command? Any advice, please!

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