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  • Avoiding Nested Queries

    - by Midhat
    How Important is it to avoid nested queries. I have always learnt to avoid them like a plague. But they are the most natural thing to me. When I am designing a query, the first thing I write is a nested query. Then I convert it to joins, which sometimes takes a lot of time to get right. And rarely gives a big performance improvement (sometimes it does) So are they really so bad. Is there a way to use nested queries without temp tables and filesort

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  • ASP.NET MVC Deployed Application Server Address

    - by Jacob Huggart
    I have an application that sends an email to a user so that they may access a web form. In the email there is just a link to the start page of this form. Currently, I have the value for the form location hardcoded. Once the app is deployed I know it is in inetpub/wwwroot/appName, which results in a URL of serverip:appPort/appName. What is the C# to get the serverip:appPort portion of the URL that I need? I think that server.mappath() might work, but for some reason I can't get to the method even though I have the necessary references.

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  • Cassandra Production ready on Windows?

    - by BlackTea
    Question anyone know of any success stories of Cassandra running on windows in a production environment? I'm doing some work on Cassandra and trying to find the correct platform for it currently the platform is windows running MS-SQLas the data store. what are the dis-advantages if any when running Cassandra on a windows environment.

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  • Django: Grouping by Dates and Servers

    - by TheLizardKing
    So I am trying to emulate google app's status page: http://www.google.com/appsstatus#hl=en but for backups for our own servers. Instead of service names on the left it'll be server names but the dates and hopefully the pagination will be there too. My models look incredibly similar to this: from django.db import models STATUS_CHOICES = ( ('UN', 'Unknown'), ('NI', 'No Issue'), ('IS', 'Issue'), ('NR', 'Not Running'), ) class Server(models.Model): name = models.CharField(max_length=32) def __unicode__(self): return self.name class Backup(models.Model): server = models.ForeignKey(Server) created = models.DateField(auto_now_add=True) modified = models.DateTimeField(auto_now=True) status = models.CharField(max_length=2, choices=STATUS_CHOICES, default='UN') issue = models.TextField(blank=True) def __unicode__(self): return u'%s: %s' % (self.server, self.get_status_display()) My issue is that I am having a hell of a time displaying the information I need. Everyday a little after midnight a cron job will run and add a row for each server for that day, defaulting on status unknown (UN). My backups.html: {% extends "base.html" %} {% block content %} <table> <tr> <th>Name</th> {% for server in servers %} <th>{{ created }}</th> </tr> <tr> <td>{{ server.name }}</td> {% for backup in server.backup_set.all %} <td>{{ backup.get_status_display }}</td> {% endfor %} </tr> {% endfor %} </table> {% endblock content %} This actually works but I do not know how to get the dates to show. Obviously {{ created }} doesn't do anything but the servers don't have create dates. Backups do and because it's a cron job there should only be X number of rows with any particular date (depending on how many servers we are following for that day). Summary I want to create a table, X being server names, Y being dates starting at today while all the cells being the status of a backup. The above model and template should hopefully give you an idea what my thought process but I am willing to alter anything. Basically I am create a fancy excel spreadsheet.

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  • How do I write this MySQL query?

    - by CT
    I am working on an Asset DB using a lamp stack. In this example consider the following 5 tables: asset, server, laptop, desktop, software All tables have a primary key of id, which is a unique asset id. Every object has all asset attributes and then depending on type of asset has additional attributes in the corresponding table. If the type is a server, desktop or laptop it also has items in the software table. Here are the table create statements: // connect to mysql server and database "asset_db" mysql_connect("localhost", "asset_db", "asset_db") or die(mysql_error()); mysql_select_db("asset_db") or die(mysql_error()); // create asset table mysql_query("CREATE TABLE asset( id VARCHAR(50) PRIMARY KEY, company VARCHAR(50), location VARCHAR(50), purchase_date VARCHAR(50), purchase_order VARCHAR(50), value VARCHAR(50), type VARCHAR(50), notes VARCHAR(200))") or die(mysql_error()); echo "Asset Table Created.</br />"; // create software table mysql_query("CREATE TABLE software( id VARCHAR(50) PRIMARY KEY, software VARCHAR(50), license VARCHAR(50))") or die(mysql_error()); echo "Software Table Created.</br />"; // create laptop table mysql_query("CREATE TABLE laptop( id VARCHAR(50) PRIMARY KEY, manufacturer VARCHAR(50), model VARCHAR(50), serial_number VARCHAR(50), esc VARCHAR(50), user VARCHAR(50), prev_user VARCHAR(50), warranty VARCHAR(50))") or die(mysql_error()); echo "Laptop Table Created.</br />"; // create desktop table mysql_query("CREATE TABLE desktop( id VARCHAR(50) PRIMARY KEY, manufacturer VARCHAR(50), model VARCHAR(50), serial_number VARCHAR(50), esc VARCHAR(50), user VARCHAR(50), prev_user VARCHAR(50), warranty VARCHAR(50))") or die(mysql_error()); echo "Desktop Table Created.</br />"; // create server table mysql_query("CREATE TABLE server( id VARCHAR(50) PRIMARY KEY, manufacturer VARCHAR(50), model VARCHAR(50), warranty VARCHAR(50))") or die(mysql_error()); echo "Server Table Created.</br />"; ?> How do I query the database so that if I search by id, I receive all related fields to that asset id? Thank you.

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  • Lock Question - When is an Update (U) lock issued?

    - by Randy Minder
    We are trying to resolve a deadlock problem. The transaction that is getting rolled back is attempting to issue an Update (U) lock on a resource that another transaction has an Exclusive (X) lock on. According to Books Online (http://msdn.microsoft.com/en-us/library/ms175519.aspx), an Update lock is supposed to prevent deadlocks, not cause them. So, my question is, why/when is an Update lock applied to a resource? We're a little confused about this because the resource that is attempting to have the Update lock applied to will not be updated by the process that is having the transaction rolled back. Thanks for your help on this. Randy

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  • LINQ Query returns nothing.

    - by gtas
    Why is this query returns 0 lines? There is a record matching the arguments. Deafkaw.Where(p => (p.ImerominiaKataxorisis >= aDate && p.ImerominiaKataxorisis <= DateTime.Now) && (p.Year == etos && p.IsYpodeigma == false) ).ToList(); Am i missing something?

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  • Are there more secure alternatives to the .Net SQLConnection class?

    - by KeyboardMonkey
    Hi SO people, I'm very surprised this issue hasn't been discussed in-depth: This article tells us how to use windbg to dump a running .Net process strings in memory. I spent much time researching the SecureString class, which uses unmanaged pinned memory blocks, and keeps the data encrypted too. Great stuff. The problem comes in when you use it's value, and assign it to the SQLConnection.ConnectionString property, which is of the System.String type. What does this mean? Well... It's stored in plain text Garbage Collection moves it around, leaving copies in memory It can be read with windbg memory dumps That totally negates the SecureString functionality! On top of that, the SQLConnection class is non-inheritable, I can't even roll my own with a SecureString property instead; Yay for closed-source. Yay. A new DAL layer is in progress, but for a new major version and for so many users it will be at least 2 years before every user is upgraded, others might stay on the old version indefinitely, for whatever reason. Because of the frequency the connection is used, marshalling from a SecureString won't help, since the immutable old copies stick in memory until GC comes around. Integrated Windows security isn't an option, since some clients don't work on domains, and other roam and connect over the net. How can I secure the connection string, in memory, so it can't be viewed with windbg?

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  • How can i return dataset perfectly from sql?

    - by Phsika
    i try to write a winform application: i dislike below codes: DataTable dt = new DataTable(); dt.Load(dr); ds = new DataSet(); ds.Tables.Add(dt); Above part of codes looks unsufficient.How can i best loading dataset? public class LoadDataset { public DataSet GetAllData(string sp) { return LoadSQL(sp); } private DataSet LoadSQL(string sp) { SqlConnection con = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"].ToString()); SqlCommand cmd = new SqlCommand(sp, con); DataSet ds; try { con.Open(); cmd.CommandType = CommandType.StoredProcedure; SqlDataReader dr = cmd.ExecuteReader(); DataTable dt = new DataTable(); dt.Load(dr); ds = new DataSet(); ds.Tables.Add(dt); return ds; } finally { con.Dispose(); cmd.Dispose(); } } }

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  • C# Tupel group limitation

    - by user609511
    How can i controll the loop of Tupel Repeatation ? Someone has give me a hint about my algorithm. I modified a little bit his algorithm. int LimCol = Convert.ToInt32(LimitColis); result = oListTUP .GroupBy(x => x.Item1) .Select(g => new { Key = g.Key, Sum = g.Sum(x => x.Item2), Poids = g.Sum(x => x.Item3), }) .Select(p => new { Key = p.Key, Items = Enumerable.Repeat(LimCol , p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, 1)), CalculPoids = p.Poids / (Enumerable.Repeat(LimCol, p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, 1))).Count() }) .SelectMany(p => p.Items.Select(i => Tuple.Create(p.Key, i, p.CalculPoids))) .ToList(); foreach (var oItem in result) { Label1.Text += oItem.Item1 + "--" + oItem.Item2 + "--" + oItem.Item3 + "<br>"; } the result with LimCol = 3 as you can see i colored with red is the problem. i expected: 0452632--3--3,75 0452632--3--3,75 0452632--3--3,75 0452632--3--3,75 essai 49--3--79,00 essai 49--2--79,00 Thanks you in advance

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  • MySQL: Column Contains Word From List of Words

    - by mellowsoon
    I have a list of words. Lets say they are 'Apple', 'Orange', and 'Pear'. I have rows in the database like this: ------------------------------------------------ |author_id | content | ------------------------------------------------ | 54 | I ate an apple for breakfast. | | 63 | Going to the store. | | 12 | Should I wear the orange shirt? | ------------------------------------------------ I'm looking for a query on an InnoDB table that will return the 1st and 3rd row, because the content column contains one or more words from my list. I know I could query the table once for each word in my list, and use LIKE and the % wildcard character, but I'm wondering if there is a single query method for such a thing?

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  • linq join query

    - by SamB09
    Hi, im trying to do a join in linq , however for some reason i cant access the primary key of a table. It's the 'h.ProjectId' that doesn't seem to be accepted. The following error is given CW1.SearchWebService.Bid does not contain a definition for 'ProjectId' and no extention method 'ProjectId' accepting a first argument of type 'CW1SearchWebService.Bid' var allProjects = ctxt.Project.ToList() ; var allBids = ctxt.Bid.ToArray();// return all bids var projects = (from project in allProjects join h in allBids on project.ProjectId equals h.ProjectId

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  • mysql whats wrong with this query?

    - by Hailwood
    I'm trying to write a query that selects from four tables campaignSentParent csp campaignSentEmail cse campaignSentFax csf campaignSentSms css Each of the cse, csf, and css tables are linked to the csp table by csp.id = (cse/csf/css).parentId The csp table has a column called campaignId, What I want to do is end up with rows that look like: | id | dateSent | emailsSent | faxsSent | smssSent | | 1 | 2011-02-04 | 139 | 129 | 140 | But instead I end up with a row that looks like: | 1 | 2011-02-03 | 2510340 | 2510340 | 2510340 | Here is the query I am trying SELECT csp.id id, csp.dateSent dateSent, COUNT(cse.parentId) emailsSent, COUNT(csf.parentId) faxsSent, COUNT(css.parentId) smsSent FROM campaignSentParent csp, campaignSentEmail cse, campaignSentFax csf, campaignSentSms css WHERE csp.campaignId = 1 AND csf.parentId = csp.id AND cse.parentId = csp.id AND css.parentId = csp.id; Adding GROUP BY did not help, so I am posting the create statements. csp CREATE TABLE `campaignsentparent` ( `id` int(11) NOT NULL AUTO_INCREMENT, `campaignId` int(11) NOT NULL, `dateSent` datetime NOT NULL, `account` int(11) NOT NULL, `status` varchar(15) NOT NULL DEFAULT 'Creating', PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=latin1 cse/csf (same structure, different names) CREATE TABLE `campaignsentemail` ( `id` int(11) NOT NULL AUTO_INCREMENT, `parentId` int(11) NOT NULL, `contactId` int(11) NOT NULL, `content` text, `subject` text, `status` varchar(15) DEFAULT 'Pending', PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=140 DEFAULT CHARSET=latin1 css CREATE TABLE `campaignsentsms` ( `id` int(11) NOT NULL AUTO_INCREMENT, `parentId` int(11) NOT NULL, `contactId` int(11) NOT NULL, `content` text, `status` varchar(15) DEFAULT 'Pending', PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=141 DEFAULT CHARSET=latin1

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  • Implementing a 1 to many relationship with SQLite

    - by Patrick
    I have the following schema implemented successfully in my application. The application connects desk unit channels to IO unit channels. The DeskUnits and IOUnits tables are basically just a list of desk/IO units and the number of channels on each. For example a desk could be 4 or 12 channel. CREATE TABLE DeskUnits (Name TEXT, NumChannels NUMERIC); CREATE TABLE IOUnits (Name TEXT, NumChannels NUMERIC); CREATE TABLE RoutingTable (DeskUnitName TEXT, DeskUnitChannel NUMERIC, IOUnitName TEXT, IOUnitChannel NUMERIC); The RoutingTable 'table' then connects each DeskUnit channel to an IOUnit channel. For example the DeskUnit called "Desk1" channel 1 may route to IOunit name "IOUnit1" channel 2, etc. So far I hope this is pretty straightforward and understandable. The problem is, however, this is a strictly 1 to 1 relationship. Any DeskUnit channel can route to only 1 IOUnit channel. Now, I need to implement a 1 to many relationship. Where any DeskUnit channel can connect to multiple IOUnit channels. I realise I may have to rearrange the tables completely, but I am not sure the best way to go about this. I am fairly new to SQLite and databases in general so any help would be appreciated. Thanks Patrick

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  • Removing "Using temporary; Using filesort" from this MySQL select+join+group by query

    - by claytontstanley
    I have the following query: select t.Chunk as LeftChunk, t.ChunkHash as LeftChunkHash, q.Chunk as RightChunk, q.ChunkHash as RightChunkHash, count(t.ChunkHash) as ChunkCount from chunksubset as t join chunksubset as q on t.ID = q.ID group by LeftChunkHash, RightChunkHash And the following explain table: id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE subsets ref PRIMARY,IDIndex,SubsetIndex SubsetIndex 767 const 522014 "Using where; Using temporary; Using filesort" 1 SIMPLE subsets eq_ref PRIMARY,IDIndex,SubsetIndex PRIMARY 771 sotero.subsets.Id,const 1 "Using where; Using index" 1 SIMPLE c ref IDIndex IDIndex 4 sotero.subsets.Id 12 "Using where" 1 SIMPLE c ref IDIndex IDIndex 4 sotero.subsets.Id 12 note the "using temporary; using filesort". When this query is run, I quickly run out of RAM (presumably b/c of the temp table), and then the HDD kicks in, and the query slows to a halt. I thought it might be an index issue, so I started adding a few that sort of made sense: Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment chunks 0 PRIMARY 1 ChunkId A 17796190 NULL NULL BTREE chunks 1 ChunkHashIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 IDIndex 1 Id A 1483015 NULL NULL BTREE chunks 1 ChunkIndex 1 Chunk A 243783 NULL NULL BTREE chunks 1 ChunkTypeIndex 1 ChunkType A 2 NULL NULL BTREE chunks 1 chunkHashByChunkIDIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 chunkHashByChunkIDIndex 2 ChunkId A 17796190 NULL NULL BTREE chunks 1 chunkHashByChunkTypeIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 chunkHashByChunkTypeIndex 2 ChunkType A 261708 NULL NULL BTREE chunks 1 chunkHashByIDIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 chunkHashByIDIndex 2 Id A 17796190 NULL NULL BTREE But still using the temporary table. The db engine is MyISAM. How can I get rid of the using temporary; using filesort in this query? Just changing to InnoDB w/o explaining the underlying cause is not a particularly satisfying answer. Besides, if the solution is to just add the proper index, then that's much easier than migrating to another db engine.

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  • Can't add domain users to Reporting Services 2008

    - by Jeremy
    I have SSRS 2008 setup on the database server. The server is part of the domain. Reporting Services is running under NetworkService. When I try to add a domain user using the web interface (Site Settings -- Security -- New Role Assignment), the page posts back but the user is not in the list. The server's log file contains the following Unhandled Exception: ui!ReportManager_0-1!954!01/12/2009-10:14:52:: Unhandled exception: System.Security.Principal.IdentityNotMappedException: Some or all identity references could not be translated. at System.Security.Principal.SecurityIdentifier.Translate(IdentityReferenceCollection sourceSids, Type targetType, Boolean forceSuccess) at System.Security.Principal.SecurityIdentifier.Translate(Type targetType) at System.Security.Principal.WindowsIdentity.GetName() at System.Security.Principal.WindowsIdentity.get_Name() at ReportingServicesHttpRuntime.RsWorkerRequest.GetServerVariable(String name) at System.Web.Security.WindowsAuthenticationModule.OnEnter(Object source, EventArgs eventArgs) at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Any one have an idea on how to fix this?

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  • mysql subquery strangely slow

    - by aviv
    I have a query to select from another sub-query select. While the two queries look almost the same the second query (in this sample) runs much slower: SELECT user.id ,user.first_name -- user.* FROM user WHERE user.id IN (SELECT ref_id FROM education WHERE ref_type='user' AND education.institute_id='58' AND education.institute_type='1' ); This query takes 1.2s Explain on this query results: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY user index first_name 152 141192 Using where; Using index 2 DEPENDENT SUBQUERY education index_subquery ref_type,ref_id,institute_id,institute_type,ref_type_2 ref_id 4 func 1 Using where The second query: SELECT -- user.id -- user.first_name user.* FROM user WHERE user.id IN (SELECT ref_id FROM education WHERE ref_type='user' AND education.institute_id='58' AND education.institute_type='1' ); Takes 45sec to run, with explain: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY user ALL 141192 Using where 2 DEPENDENT SUBQUERY education index_subquery ref_type,ref_id,institute_id,institute_type,ref_type_2 ref_id 4 func 1 Using where Why is it slower if i query only by index fields? Why both queries scans the full length of the user table? Any ideas how to improve? Thanks.

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