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• Looking for a central image database and tagging system for a group of users

  - by jstarek

  I'm doing IT support for a small volunteer organisation who needs to centrally store and organize around 2500 photos. Can anyone here recommend a database or similar system which matches the following criteria: Intuitive to use for users with little computer experience Multi-user support, ideally with integration in our existing LDAP user directory Should have a web-interface Not a hosted solution like Picasa (because we have a rather slow internet connection with very slow upload) Should allow tagging of images, sorting by various criteria and storing copyright information If there are native GNOME and/or Windows clients for the tool, that would be a great benefit. Many thanks in advance!

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• Installing Oracle11gr2 on redhat linux

  - by KItis

  I have basic question about installing applications on linux operating system. i am going to express my issue considering oracle db installation as a example. when installing oracle database , i created a user group called dba and and user in this group called ora112. so this users is allowed to install database. so my question is if ora112 uses umaks is set to 077, then no other uses will be able to configure oracle database. why do we need to follow this practice. is it a accepted procedure in application installation on Linux. please share your experience with me. thanks in advance for looking into this issue say i install java application on this way. then no other application which belongs to different user account won't be able use java running on this computer because of this access restriction.

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• Setup ejabberd with SQL Server 2008

  - by wonster

  Here's what I have got so far. Windows 2008 Server 64 bit. Installed the latest version of ejabberd, ejabberd-2.1.8-windows-installer.exe. The windows service starts up fine but seems ineffective. However, using the start & stop scripts work. I am able to login to the admin page which so far doesn't seem that versatile. Opened up ports 5222, 5226 and 5280 for my workstation to talk to the server. I've got Spark and Jabbear Windows clients to register, login and instant message with multiple accounts using the server. After confirming that I've got the very basics working, I've decided to make use of SQL Server 2008 as the database. Reason? Mainly, I am very comfortable with SQL Server. I can deal with redundancy, failover, data analysis easily. Not sure if ejabberd's built in DB provides all that. Following the instructions from ejabberd's documentation, I setup a system DSN that points to another physical database. The DSN checks out fine. (Tried both Named Pipes and TCP/IP) Modified ejabberd.cfg. Commented line %%{auth_method, internal} and uncommented line {auth_method, odbc} Uncommented and modified {odbc_server, "DSN=ejabberd;UID=somelogin;PWD=somepassword"}. After making these changes, I restarted. No errors are found in the log files. The jabber clients are no longer able to register new accounts. I'm not sure where to look for errors besides the /logs/ folder as I'm new to all this. I am basically stuck here on step 5. Has anyone got this setup to work recently? Some of the posts I've found around are years old and of no help. I can't be the only one setting up ejabberd with MS SQL. Any help would be appreciated!

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• Log backups "stalling" on SQL 2008?

  - by MattK

  I have interited a box running SQL Server 2008 and Windows 2003, and have had a few events where largeish (35GB) log backups "stall", both before and after the installation of SQL 2008 SP1. The server log ships to a standby, so regular log backups are taken at 15 minute intervals. However, after an index reorg causes the log to grow to about 35GB (on a DB with about 17GB of data), the next log backup runs to ~95% completion, then seems to stop. The process shows as suspended, with a wait state of BACKUPIO. CPU, read, and write activity on the SPID also does not change, and the process stays in this state for hours, when normally a backup of this size should complete in about 20 minutes. This server has a single RAID-1 volume, thus the source database files and destination backup files are on the same volume. However, I cannot determine if another process is blocking the backup. The backup SPID cannot be killed, and the only way to terminate the log backup and clear the lock on the backup file is to cycle the SQL Server service. There was one event where the backup terminated completely, with an error that another process had locked the backup file, but no details about what that process was. Can anyone suggest a cause or diagnostic process to this situation?

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• SQL Server 2005/2008 Licensing Decision

  - by Hakim

  Hello, I have purchased a dedicated server from a reputable Hosting company. They only have Windows Server 2008 OS installed on it and NO Sql server. Server Configuration is Intel Dual core Processor with 2GB of RAM and 100GB HDD. I wanted to host my web services on that server which will be using the MS SQL Server 2005 at the backend.There are multiple web services and each using a different Database. Microsoft has CAL basis Licensing , Which I understand is based on number of users accessing the database directly ( I may be wrong ) . But my users will be accessing the webservice and no direct connection to the database as such. Yes but the number of users accessing the web server cannot be known and is not under my control. Which Licensing is best suited for this kind of setup ? I don't need analysing and BI services right now ,but i may want to upgrade that in future may be. Any help will be appreciated. Thanks

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• cannot get mssql working with sql server 2005

  - by Ryan

  I'm a MySQL/Apache user, trying my hand with IIS and SQL server, so please, if this is a stupid question have patience. I'm using IIS version 7.5. PHP version 5.3.13 and SQL server 2005 IIS is running on port 90, not sure if that will make a difference or not. I know my sql server is running because I can explore/connect to it in Server management studio. I know php is configured properly, because //localhost:90/phpinfo.php works fine. I updated the php_msql.dll extension in phpinfo to: extension=ext/php_msql.dll EDIT- However, when I run phpinfo() under the "configure command" row, this is present: --without-mssql I found/downloaded the ntwdblib.dll and placed it in both sys32 and php root. All these things were supposed to fix the issue, and they haven't. This is the code I'm using, straight from php.net: <?php // Server in the this format: <computer>\<instance name> or // <server>,<port> when using a non default port number $server = 'localhost'; // Connect to MSSQL $link = mssql_connect($server, 'uname', 'pwd'); if (!$link) { die('Something went wrong while connecting to MSSQL'); } ?> obviously I'm using a real username and password, but when I load the file in my browser, I receive a 500 error. Upon checking the log, this is what is displayed: 2012-06-25 12:41:29 ::1 GET /test.php - 90 - ::1 Mozilla/5.0+(Windows+NT+6.1;+WOW64)+AppleWebKit/536.5+(KHTML,+like+Gecko)+Chrome/19.0.1084.56+Safari/536.5 500 0 0 5 That (to me) doesn't help me much. What am I doing wrong? Thank you

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• Cannot install SQL Server CE 4

  - by Manos Dilaverakis

  I'm trying to install SQL Server CE 4 on a WinXP Pro SP3 machine. I double-click on the file and absolutely nothing happens. There is nothing in the event viewer and the only effect I can see is the addition of an empty, randomly named folder in C:\ which looks something like C:\7c59aaeb5e43f6bdcb2430e923 I've tried this with both SQL Server CE 4 and the SP1 version. I've tried disabling the AV (Nod32) file protection but it didn't make a difference. I've checked the installed program list in case it's already installed, but I don't see it anywhere. I checked in C:\Program Files\Microsoft SQL Server Compact Edition\ and there's only the \3.5 folder in there from the already installed 3.5 version. Does anyone know what's going on or how I can further diagnose the problem? Edit in response to Ramhound: I have .NET 4 installed. Why, does it need a particular version? Edit in response to leinad13 I tried Process Explorer and filtered by the name of the temporary folder created. I see the following, but can't make much sense of it.

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• Issues with "There is already an object named 'xxx' in the database'

  - by Hoser

  I'm fairly new to SQL so this may be an easy mistake, but I haven't been able to find a solid solution anywhere else. Problem is whenever I try to use my temp table, it tells me it cannot be used because there is already an object with that name. I frequently try switching up the names, and sometimes it'll let me work with the table for a little while, but it never lasts for long. Am I dropping the table incorrectly? Also, I've had people suggest to just use a permanent table, but this database does not allow me to do that. create table #RandomTableName(NameOfObject varchar(50), NameOfCounter varchar(50), SampledValue decimal) select vPerformanceRule.ObjectName, vPerformanceRule.CounterName, Perf.vPerfRaw.SampleValue into #RandomTableName from vPerformanceRule, vPerformanceRuleInstance, Perf.vPerfRaw where (ObjectName like 'Processor' AND CounterName like '% Processor Time') OR(ObjectName like 'System' AND CounterName like 'Processor Queue Length') OR(ObjectName like 'Memory' AND CounterName like 'Pages/Sec') OR(ObjectName like 'Physical Disk' AND CounterName like 'Avg. Disk Queue Length') OR(ObjectName like 'Physical Disk' AND CounterName like 'Avg. Disk sec/Read') OR(ObjectName like 'Physical Disk' and CounterName like '% Disk Time') OR(ObjectName like 'Logical Disk' and CounterName like '% Free Space' AND SampleValue > 70 AND SampleValue < 100) order by ObjectName, SampleValue drop table #RandomTableName

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• SQL Server: Network pauses after installing cheap SATA card: Is there a solution?

  - by samsmith

  At the risk of being assigned to the "bad DBA" club... I did something desperate, and may have to undo it. Problem: After installing a low cost eSATA board, my SQL Server is intermittently unresponsive (seemingly when there is a lot of IO to the eSATA drive). Questions: 1) Is there a solution to the intermittent unresponsiveness that allows me to keep the eSATA in place? 2) Whether or not (1==true): What is a decent, low cost way to add 1-3 TB storage to SQL for non-critical SQL DBs? Detail: Our SAN is full, and expanding it is costly and will take a month. I have a pressing need to add 1-3 TB for some development DBs (e.g. not mission critical; data loss is OK). As a bandaid, I threw a $20 eSATA PCI board in the Dell 1950 server, and attached an external 2TB eSATA drive. This seemed to work fine, but I notice that our production SQL DBs, and even remote desktop, now experience network "pauses" that they never did before (with both SQL client apps and remote desktop throwing "networking problem" errors). This SQL Server has lots of memory, and runs an instance of SQL 2005 (where all line of business apps reside) and an instance SQL 2008 (for development db's). SQL Server RAM has been appropriately configured, and this setup has run great for years. The server is: Dell 1950 Win2003 x64 14GB RAM PERC controller, 2 mirrored hd's internal Dell SAN over gbit ethernet, dual homed 2 PCIx slots (1 used by NIC for SAN, 1 now in use for eSATA board) Thank you for suggestions!

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• Hourly SQL Server 2005 Slowness (Possibly caused by SYSTEM)

  - by Zorlack

  We're trying to diagnose the cause of slowness on our Database server. We're running the latest rev SQL Server 2005 on Windows 2008x64. The behavior that we're seeing is this: We see the SYSTEM process spike one of the CPUs for about 2 minutes, during this time SQL server slows down by a factor of 10. The slowness lasts until SYSTEM is done, then in an hour everything starts again. During these slowdowns disk writes don't spike, paging doesn't spike, the only noticeable precursor we see is that SYSTEM maxes out one of the sixteen (HT)CPUs. Note that this doesn't happen at the top of the hour, it just happens once an hour, and it shifts a bit depending on the length of the incident. At the moment this is causing intermittent slowdowns, but when the server is really busy it can cause Worker Thread starvation. The server is a Dual Quad Dell R710 with 96GB of RAM and RAID10 data/log disks. Has anyone experienced this kind of problem? Does anyone know where we should look? Edit: SQL Server Version is 9.0.4035

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• Two way replication

  - by Nidzaaaa

  I have a little problem... I have this case: -2 server instances -2 Databases -1 Table (5 columns) From server 1 I created publication to replicate all columns of table I have in 1. DB From server 2 I created subscription to pull all columns from table which is in server 1 DB But now, I need to publicate one columns of same table from server 2 to server 1 and also it has to be in same DB... I tried with using logic and creating publication for server 2 and subscription on server 1 but there is error appearing "You have selected the Publisher as a Subscriber and entered a subscription database that is the same as the publishing database. Select another subscription database." I hope someone understood my problem and have an answer for me, thanks in advance... p.s. Ask for more info if you need ...

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• How to salvage SQL server 2008 query from KILLED/ROLLBACK state?

  - by littlegreen

  I have a stored procedure that inserts batches of millions of rows, emerging from a certain query, into an SQL database. It has one parameter selecting the batch; when this parameter is omitted, it will gather a list of batches and recursively call itself, in order to iterate over batches. In (pseudo-)code, it looks something like this: CREATE PROCEDURE spProcedure AS BEGIN IF @code = 0 BEGIN ... WHILE @@Fetch_Status=0 BEGIN EXEC spProcedure @code FETCH NEXT ... INTO @code END END ELSE BEGIN -- Disable indexes ... INSERT INTO table SELECT (...) -- Enable indexes ... Now it can happen that this procedure is slow, for whatever reason: it can't get a lock, one of the indexes it uses is misdefined or disabled. In that case, I want to be able kill the procedure, truncate and recreate the resulting table, and try again. However, when I try and kill the procedure, the process frequently oozes into a KILLED/ROLLBACK state from which there seems to be no return. From Google I have learned to do an sp_lock, find the spid, and then kill it with KILL <spid>. But when I try to kill it, it tells me SPID 75: transaction rollback in progress. Estimated rollback completion: 0%. Estimated time remaining: 554 seconds. I did find a forum message hinting that another spid should be killed before the other one can start a rollback. But that didn't work for me either, plus I do not understand, why that would be the case... could it be because I am recursively calling my own stored procedure? (But it should be having the same spid, right?) In any case, my process is just sitting there, being dead, not responding to kills, and locking the table. This is very frustrating, as I want to go on developing my queries, not waiting hours on my server sitting dead while pretending to be finishing a supposed rollback. Is there some way in which I can tell the server not to store any rollback information for my query? Or not to allow any other queries to interfere with the rollback, so that it will not take so long? Or how to rewrite my query in a better way, or how kill the process successfully without restarting the server?

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• How to salvage SQL server 2008 query from KILLED/ROLLBACK state without waiting half a day?

  - by littlegreen

  I have a stored procedure that inserts batches of millions of rows, emerging from a certain query, into an SQL database. It has one parameter selecting the batch; when this parameter is omitted, it will gather a list of batches and recursively call itself, in order to iterate over batches. In (pseudo-)code, it looks something like this: CREATE PROCEDURE spProcedure AS BEGIN IF @code = 0 BEGIN ... WHILE @@Fetch_Status=0 BEGIN EXEC spProcedure @code FETCH NEXT ... INTO @code END END ELSE BEGIN -- Disable indexes ... INSERT INTO table SELECT (...) -- Enable indexes ... Now it can happen that this procedure is slow, for whatever reason: it can't get a lock, one of the indexes it uses is misdefined or disabled. In that case, I want to be able kill the procedure, truncate and recreate the resulting table, and try again. However, when I try and kill the procedure, the process frequently oozes into a KILLED/ROLLBACK state from which there seems to be no return. From Google I have learned to do an sp_lock, find the spid, and then kill it with KILL <spid>. But when I try to kill it, it tells me SPID 75: transaction rollback in progress. Estimated rollback completion: 0%. Estimated time remaining: 554 seconds. I did find a forum message hinting that another spid should be killed before the other one can start a rollback. But that didn't work for me either, plus I do not understand, why that would be the case... could it be because I am recursively calling my own stored procedure? (But it should be having the same spid, right?) In any case, my process is just sitting there, being dead, not responding to kills, and locking the table. This is very frustrating, as I want to go on developing my queries, not waiting hours on my server sitting dead while pretending to be finishing a supposed rollback. Is there some way in which I can tell the server not to store any rollback information for my query? Or not to allow any other queries to interfere with the rollback, so that it will not take so long? Or how to rewrite my query in a better way, or how kill the process successfully without restarting the server?

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• sp_ssiscatalog v1.0.1.0 now available for download

  - by jamiet

  13 days ago I wrote a blog post entitled Introducing sp_ssiscatalog (v1.0.0.0) in which I first made mention of sp_ssiscatalog, an open source stored procedure intended to make it easy to query the SSIS Catalog. I have been working on some enhancements since then and hence v1.0.1.0 is now available for download from Codeplex. What’s new in this release This release includes the following enhancements: [execution_id] now gets returned in a call to EXEC [dbo].[sp_ssiscatalog] @operation_type='exec'; Filter events by specifying packages to ignore EXEC [dbo].[sp_ssiscatalog] @operation_type='exec',@exec_events_packagesexcluded='SomePackage.dtsx,AnotherPackage.dtsx'; [event_message_id] is now returned in a list of events List of executions can now be filtered via a minimum and maximum execution_id EXEC [dbo].[sp_ssiscatalog] @operation_type='execs',@execs_minimum_execution_id=198,@execs_maximum_execution_id=201 Events resultsets now have a field, [event_message_context_xml] that contains an XML document containing all [event_message_context] info (if any exists) Installation instructions Download the zip file at DB v1.0.1.0. It contains two files, SsisReportingPack.dacpac & SSISDB.dacpac Unzip to a folder of your choosing Open a command prompt and change to the directory into which you unzipped the files Execute: "%PROGRAMFILES(x86)%\Microsoft SQL Server\110\DAC\bin\sqlpackage.exe" /a:Publish /tdn:SsisReportingPack /sf:SSISReportingPack.dacpac /v:SSISDB=SSISDB /tsn:(local) (/tsn specifies the target server. Change as appropriate.) If everything works OK you’ll see something like the following: or depending on whether the target database already exists or not This will create a database called [SsisReportingPack] which contains [dbo].[sp_ssiscatalog] Feedback is welcomed! @Jamiet

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• Custom Database integration with MOSS 2007

  - by Bob

  Hopefully someone has been down this road before and can offer some sound advice as far as which direction I should take. I am currently involved in a project in which we will be utilizing a custom database to store data extracted from excel files based on pre-established templates (to maintain consistency). We currently have a process (written in C#.Net 2008) that can extract the necessary data from the spreadsheets and import it into our custom database. What I am primarily interested in is figuring out the best method for integrating that process with our portal. What I would like to do is let SharePoint keep track of the metadata about the spreadsheet itself and let the custom database keep track of the data contained within the spreadsheet. So, one thing I need is a way to link spreadsheets from SharePoint to the custom database and vice versa. As these spreadsheets will be updated periodically, I need tried and true way of ensuring that the data remains synchronized between SharePoint and the custom database. I am also interested in finding out how to use the data from the custom database to create reports within the SharePoint portal. Any and all information will be greatly appreciated.

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• IList<Item> Collection Class accessing database

  - by Mike

  Hi, I have a database with Users. Users have Items. These Items can change actively. How do you access the items in a collection type format? For the user, I fill all the user properties at the time of instantiation. If I load the user's items at the time of the instantiation, and the items change, they will have old data. I was thinking, maybe I need an ItemCollection class and have that a field/property apart of the user class, that way to traverse all the user's items I could use a foreach loop. So, my question is, what is the best practice/best way of accessing the items from a database using some sort of collection? On accessing the particular Item, it needs to get the latest database information, and when the user does do a foreach loop, the latest item information must be available. I.e. What I'm trying to do Console.WriteLine(User.Items[3].ID); returns 5. //this updates the item information and saves it to the database. User.Items[3].ID = 13; //Add a new item to the database. User.Items.Add(new Item { id = 17}); foreach (Item item in User.Items) { //this would traverse all items in the database. //not some cached copy at the time of instantiation of the user. }

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• How can I extend this SQL query to find the k nearest neighbors?

  - by Smigs

  I have a database full of two-dimensional data - points on a map. Each record has a field of the geometry type. What I need to be able to do is pass a point to a stored procedure which returns the k nearest points (k would also be passed to the sproc, but that's easy). I've found a query at http://blogs.msdn.com/isaac/archive/2008/10/23/nearest-neighbors.aspx which gets the single nearest neighbour, but I can't figure how to extend it to find the k nearest neighbours. This is the current query - T is the table, g is the geometry field, @x is the point to search around, Numbers is a table with integers 1 to n: DECLARE @start FLOAT = 1000; WITH NearestPoints AS ( SELECT TOP(1) WITH TIES *, T.g.STDistance(@x) AS dist FROM Numbers JOIN T WITH(INDEX(spatial_index)) ON T.g.STDistance(@x) < @start*POWER(2,Numbers.n) ORDER BY n ) SELECT TOP(1) * FROM NearestPoints ORDER BY n, dist The inner query selects the nearest non-empty region and the outer query then selects the top result from that region; the outer query can easily be changed to (e.g.) SELECT TOP(20), but if the nearest region only contains one result, you're stuck with that. I figure I probably need to recursively search for the first region containing k records, but without using a table variable (which would cause maintenance problems as you have to create the table structure and it's liable to change - there're lots of fields), I can't see how.

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• Best way to randomly select columns from random rows of SQL results.

  - by LesterDove

  A search of SO yields many results describing how to select random rows of data from a database table. My requirement is a bit different, though, in that I'd like to select individual columns from across random rows in the most efficient/random/interesting way possible. To better illustrate: I have a large Customers table, and from that I'd like to generate a bunch of fictitious demo Customer records that aren't real people. I'm thinking of just querying randomly from the Customers table, and then randomly pairing FirstNames with LastNames, Address, City, State, etc. So if this is my real Customer data (simplified): FirstName LastName State ========================== Sally Simpson SD Will Warren WI Mike Malone MN Kelly Kline KS Then I'd generate several records that look like this: FirstName LastName State ========================== Sally Warren MN Kelly Malone SD Etc. My initial approach works, but it lacks the elegance that I'm hoping the final answer will provide. (I'm particularly unhappy with the repetitiveness of the subqueries, and the fact that this solution requires a known/fixed number of fields and therefore isn't reusable.) SELECT FirstName = (SELECT TOP 1 FirstName FROM Customer ORDER BY newid()), LastName= (SELECT TOP 1 LastNameFROM Customer ORDER BY newid()), State = (SELECT TOP 1 State FROM Customer ORDER BY newid()) Thanks!

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• Looking for combinations of server and embedded database engines

  - by codeelegance

  I'm redesigning an application that will be run as both a single user and multiuser application. It is a .NET 2.0 application. I'm looking for server and embedded databases that work well together. I want to deploy the embedded database in the single user setup and of course, the server in the multiuser setup. Past releases have been based on MSDE but in the past year we've been having a lot of install issues: new installs hanging and leaving the system in an unknown state, upgrades disconnecting the database, etc. I migrated the application to SQL Server 2005 and the install is more reliable (as long as a user doesn't try to install over a broken MSDE installation). Since next year's release will be a complete redesign I figured now's the best time to address the database issue as well. The database has been abstracted from the rest of the application so I just need to choose which database(s) to use and write an implementation for each one. So far I've considered: SQL Server/ SQL Server Compact Edition Firebird (same DB engine is available in two different server modes and an embedded dll) Each has its own merits but I'm also interested in any other suggestions. This is a fairly simple program and its data requirements are simple as well. I don't expect it to strain whatever database I eventually choose. So easy configuration and deployment hold more weight than performance.

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• Modifying SQL Database on Shared Hosting

  - by apocalypse9

  I have a live database on a shared hosting server. I am making some major changes to my site's code and I would like to fix some stupid mistakes I made in initially designing the database. These changes involve altering the size of a large number of fields, and enforcing referential integrity between tables properly. I would like to make the changes on both my local test server and the remote server if possible. I should note that while I'm fairly comfortable with writing complex queries to handle data, I have very little experience modifying database structure without a graphical interface. I can access the remote database in the visual studio database explorer but I can not use that for anything other than data manipulation. I installed Sql Management Studio express last night and after 40+ crashes I gave up - I couldn't even patch the damn thing. The remote server is SQL 2005 / The MyLittleAdmin web interface is available. So my question is what is the best way to accomplish these changes. Is there a graphical interface I can use on the remote server? If not is there an easy way to copy the database to my local machine, fix it, and re upload? Finally if none of the above are viable does anyone have links to a decent info on fixing referential integrity via query? Sorry for the somewhat general question - I feel like I am making this far harder than it should be but after searching / trying all night i haven't gotten anywhere. Thanks in advance for the help. I really appreciate it. ...Also does anyone have a time machine I can borrow- I need to go kick my past self's ass for this.

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• Is it better to use a relational database or document-based database for an app like Wufoo?

  - by mboyle

  I'm working on an application that's similar to Wufoo in that it allows our users to create their own databases and collect/present records with auto generated forms and views. Since every user is creating a different schema (one user might have a database of their baseball card collection, another might have a database of their recipes) our current approach is using MySQL to create separate databases for every user with its own tables. So in other words, the databases our MySQL server contains look like: main-web-app-db (our web app containing tables for users account info, billing, etc) user_1_db (baseball_cards_table) user_2_db (recipes_table) .... And so on. If a user wants to set up a new database to keep track of their DVD collection, we'd do a "create database ..." with "create table ...". If they enter some data in and then decide they want to change a column we'd do an "alter table ....". Now, the further along I get with building this out the more it seems like MySQL is poorly suited to handling this. 1) My first concern is that switching databases every request, first to our main app's database for authentication etc, and then to the user's personal database, is going to be inefficient. 2) The second concern I have is that there's going to be a limit to the number of databases a single MySQL server can host. Pretending for a moment this application had 500,000 user databases, is MySQL designed to operate this way? What if it were a million, or more? 3) Lastly, is this method going to be a nightmare to support and scale? I've never heard of MySQL being used in this way so I do worry about how this affects things like replication and other methods of scaling. To me, it seems like MySQL wasn't built to be used in this way but what do I know. I've been looking at document-based databases like MongoDB, CouchDB, and Redis as alternatives because it seems like a schema-less approach to this particular problem makes a lot of sense. Can anyone offer some advice on this?

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• Database choices

  - by flobadob

  I have a prickly design issue regarding the choice of database technologies to use for a group of new applications. The final suite of applications would have the following database requirements... Central databases (more than one database) using mysql (myst be mysql due to justhost.com). An application to be written which accesses the multiple mysql databases on the web host. This application will also write to local serverless database (sqlite/firebird/vistadb/whatever). Different flavors of this application will be created for windows (.NET), windows mobile, android if possible, iphone if possible. So, the design task is to minimise the quantity of code to achieve this. This is going to be tricky since the languages used are already c# / java (android) and objc (iphone). Not too worried about that, but can the work required to implement the various database access layers be minimised? The serverless database will hold similar data to the mysql server, so some kind of inheritance in the DAL would be useful. Looking at hibernate/nhibernate and there is linq to whatever. So many choices!

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• How can I exclude LEFT JOINed tables from TOP in SQL Server?

  - by Kalessin

  Let's say I have two tables of books and two tables of their corresponding editions. I have a query as follows: SELECT TOP 10 * FROM (SELECT hbID, hbTitle, hbPublisherID, hbPublishDate, hbedID, hbedDate FROM hardback LEFT JOIN hardbackEdition on hbID = hbedID UNION SELECT pbID, pbTitle, pbPublisher, pbPublishDate, pbedID, pbedDate FROM paperback Left JOIN paperbackEdition on pbID = pbedID ) books WHERE hbPublisherID = 7 ORDER BY hbPublishDate DESC If there are 5 editions of the first two hardback and/or paperback books, this query only returns two books. However, I want the TOP 10 to apply only to the number of actual book records returned. Is there a way I can select 10 actual books, and still get all of their associated edition records? In case it's relevant, I do not have database permissions to CREATE and DROP temporary tables. Thanks for reading! Update To clarify: The paperback table has an associated table of paperback editions. The hardback table has an associated table of hardback editions. The hardback and paperback tables are not related to each other except to the user who will (hopefully!) see them displayed together.

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• SQL Server and Hyper-V Dynamic Memory - Part 1

  - by SQLOS Team

  SQL and Dynamic Memory Blog Post Series   Hyper-V Dynamic Memory is a new feature in Windows Server 2008 R2 SP1 that allows the memory assigned to guest virtual machines to vary according to demand. Using this feature with SQL Server is supported, but how well does it work in an environment where available memory can vary dynamically, especially since SQL Server likes memory, and is not very eager to let go of it? The next three posts will look at this question in detail. In Part 1 Serdar Sutay, a program manager in the Windows Hyper-V team, introduces Dynamic Memory with an overview of the basic architecture, configuration and monitoring concepts. In subsequent parts we will look at SQL Server memory handling, and develop some guidelines on using SQL Server with Dynamic Memory.   Part 1: Dynamic Memory Introduction   In virtualized environments memory is often the bottleneck for reaching higher VM densities. In Windows Server 2008 R2 SP1 Hyper-V introduced a new feature “Dynamic Memory” to improve VM densities on Hyper-V hosts. Dynamic Memory increases the memory utilization in virtualized environments by enabling VM memory to be changed dynamically when the VM is running.   This brings up the question of how to utilize this feature with SQL Server VMs as SQL Server performance is very sensitive to the memory being used. In the next three posts we’ll discuss the internals of Dynamic Memory, SQL Server Memory Management and how to use Dynamic Memory with SQL Server VMs.   Memory Utilization Efficiency in Virtualized Environments   The primary reason memory is usually the bottleneck for higher VM densities is that users tend to be generous when assigning memory to their VMs. Here are some memory sizing practices we’ve heard from customers:   ·         I assign 4 GB of memory to my VMs. I don’t know if all of it is being used by the applications but no one complains. ·         I take the minimum system requirements and add 50% more. ·         I go with the recommendations provided by my software vendor.   In reality correctly sizing a virtual machine requires significant effort to monitor the memory usage of the applications. Since this is not done in most environments, VMs are usually over-provisioned in terms of memory. In other words, a SQL Server VM that is assigned 4 GB of memory may not need to use 4 GB.   How does Dynamic Memory help?   Dynamic Memory improves the memory utilization by removing the requirement to determine the memory need for an application. Hyper-V determines the memory needed by applications in the VM by evaluating the memory usage information in the guest with Dynamic Memory. VMs can start with a small amount of memory and they can be assigned more memory dynamically based on the workload of applications running inside.   Overview of Dynamic Memory Concepts   ·         Startup Memory: Startup Memory is the starting amount of memory when Dynamic Memory is enabled for a VM. Dynamic Memory will make sure that this amount of memory is always assigned to the VMs by default.   ·         Maximum Memory: Maximum Memory specifies the maximum amount of memory that a VM can grow to with Dynamic Memory. ·         Memory Demand: Memory Demand is the amount determined by Dynamic Memory as the memory needed by the applications in the VM. In Windows Server 2008 R2 SP1, this is equal to the total amount of committed memory of the VM. ·         Memory Buffer: Memory Buffer is the amount of memory assigned to the VMs in addition to their memory demand to satisfy immediate memory requirements and file cache needs.   Once Dynamic Memory is enabled for a VM, it will start with the “Startup Memory”. After the boot process Dynamic Memory will determine the “Memory Demand” of the VM. Based on this memory demand it will determine the amount of “Memory Buffer” that needs to be assigned to the VM. Dynamic Memory will assign the total of “Memory Demand” and “Memory Buffer” to the VM as long as this value is less than “Maximum Memory” and as long as physical memory is available on the host.   What happens when there is not enough physical memory available on the host?   Once there is not enough physical memory on the host to satisfy VM needs, Dynamic Memory will assign less than needed amount of memory to the VMs based on their importance. A concept known as “Memory Weight” is used to determine how much VMs should be penalized based on their needed amount of memory. “Memory Weight” is a configuration setting on the VM. It can be configured to be higher for the VMs with high performance requirements. Under high memory pressure on the host, the “Memory Weight” of the VMs are evaluated in a relative manner and the VMs with lower relative “Memory Weight” will be penalized more than the ones with higher “Memory Weight”.   Dynamic Memory Configuration   Based on these concepts “Startup Memory”, “Maximum Memory”, “Memory Buffer” and “Memory Weight” can be configured as shown below in Windows Server 2008 R2 SP1 Hyper-V Manager. Memory Demand is automatically calculated by Dynamic Memory once VMs start running.     Dynamic Memory Monitoring    In Windows Server 2008 R2 SP1, Hyper-V Manager displays the memory status of VMs in the following three columns:         ·         Assigned Memory represents the current physical memory assigned to the VM. In regular conditions this will be equal to the sum of “Memory Demand” and “Memory Buffer” assigned to the VM. When there is not enough memory on the host, this value can go below the Memory Demand determined for the VM. ·         Memory Demand displays the current “Memory Demand” determined for the VM. ·         Memory Status displays the current memory status of the VM. This column can represent three values for a VM: o   OK: In this condition the VM is assigned the total of Memory Demand and Memory Buffer it needs. o   Low: In this condition the VM is assigned all the Memory Demand and a certain percentage of the Memory Buffer it needs. o   Warning: In this condition the VM is assigned a lower memory than its Memory Demand. When VMs are running in this condition, it’s likely that they will exhibit performance problems due to internal paging happening in the VM.    So far so good! But how does it work with SQL Server?   SQL Server is aggressive in terms of memory usage for good reasons. This raises the question: How do SQL Server and Dynamic Memory work together? To understand the full story, we’ll first need to understand how SQL Server Memory Management works. This will be covered in our second post in “SQL and Dynamic Memory” series. Meanwhile if you want to dive deeper into Dynamic Memory you can check the below posts from the Windows Virtualization Team Blog:   http://blogs.technet.com/virtualization/archive/2010/03/18/dynamic-memory-coming-to-hyper-v.aspx   http://blogs.technet.com/virtualization/archive/2010/03/25/dynamic-memory-coming-to-hyper-v-part-2.aspx   http://blogs.technet.com/virtualization/archive/2010/04/07/dynamic-memory-coming-to-hyper-v-part-3.aspx   http://blogs.technet.com/b/virtualization/archive/2010/04/21/dynamic-memory-coming-to-hyper-v-part-4.aspx   http://blogs.technet.com/b/virtualization/archive/2010/05/20/dynamic-memory-coming-to-hyper-v-part-5.aspx   http://blogs.technet.com/b/virtualization/archive/2010/07/12/dynamic-memory-coming-to-hyper-v-part-6.aspx   - Serdar Sutay   Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• SQL Server and Hyper-V Dynamic Memory - Part 1

  - by SQLOS Team

  SQL and Dynamic Memory Blog Post Series   Hyper-V Dynamic Memory is a new feature in Windows Server 2008 R2 SP1 that allows the memory assigned to guest virtual machines to vary according to demand. Using this feature with SQL Server is supported, but how well does it work in an environment where available memory can vary dynamically, especially since SQL Server likes memory, and is not very eager to let go of it? The next three posts will look at this question in detail. In Part 1 Serdar Sutay, a program manager in the Windows Hyper-V team, introduces Dynamic Memory with an overview of the basic architecture, configuration and monitoring concepts. In subsequent parts we will look at SQL Server memory handling, and develop some guidelines on using SQL Server with Dynamic Memory.   Part 1: Dynamic Memory Introduction   In virtualized environments memory is often the bottleneck for reaching higher VM densities. In Windows Server 2008 R2 SP1 Hyper-V introduced a new feature “Dynamic Memory” to improve VM densities on Hyper-V hosts. Dynamic Memory increases the memory utilization in virtualized environments by enabling VM memory to be changed dynamically when the VM is running.   This brings up the question of how to utilize this feature with SQL Server VMs as SQL Server performance is very sensitive to the memory being used. In the next three posts we’ll discuss the internals of Dynamic Memory, SQL Server Memory Management and how to use Dynamic Memory with SQL Server VMs.   Memory Utilization Efficiency in Virtualized Environments   The primary reason memory is usually the bottleneck for higher VM densities is that users tend to be generous when assigning memory to their VMs. Here are some memory sizing practices we’ve heard from customers:   ·         I assign 4 GB of memory to my VMs. I don’t know if all of it is being used by the applications but no one complains. ·         I take the minimum system requirements and add 50% more. ·         I go with the recommendations provided by my software vendor.   In reality correctly sizing a virtual machine requires significant effort to monitor the memory usage of the applications. Since this is not done in most environments, VMs are usually over-provisioned in terms of memory. In other words, a SQL Server VM that is assigned 4 GB of memory may not need to use 4 GB.   How does Dynamic Memory help?   Dynamic Memory improves the memory utilization by removing the requirement to determine the memory need for an application. Hyper-V determines the memory needed by applications in the VM by evaluating the memory usage information in the guest with Dynamic Memory. VMs can start with a small amount of memory and they can be assigned more memory dynamically based on the workload of applications running inside.   Overview of Dynamic Memory Concepts   ·         Startup Memory: Startup Memory is the starting amount of memory when Dynamic Memory is enabled for a VM. Dynamic Memory will make sure that this amount of memory is always assigned to the VMs by default.   ·         Maximum Memory: Maximum Memory specifies the maximum amount of memory that a VM can grow to with Dynamic Memory. ·         Memory Demand: Memory Demand is the amount determined by Dynamic Memory as the memory needed by the applications in the VM. In Windows Server 2008 R2 SP1, this is equal to the total amount of committed memory of the VM. ·         Memory Buffer: Memory Buffer is the amount of memory assigned to the VMs in addition to their memory demand to satisfy immediate memory requirements and file cache needs.   Once Dynamic Memory is enabled for a VM, it will start with the “Startup Memory”. After the boot process Dynamic Memory will determine the “Memory Demand” of the VM. Based on this memory demand it will determine the amount of “Memory Buffer” that needs to be assigned to the VM. Dynamic Memory will assign the total of “Memory Demand” and “Memory Buffer” to the VM as long as this value is less than “Maximum Memory” and as long as physical memory is available on the host.   What happens when there is not enough physical memory available on the host?   Once there is not enough physical memory on the host to satisfy VM needs, Dynamic Memory will assign less than needed amount of memory to the VMs based on their importance. A concept known as “Memory Weight” is used to determine how much VMs should be penalized based on their needed amount of memory. “Memory Weight” is a configuration setting on the VM. It can be configured to be higher for the VMs with high performance requirements. Under high memory pressure on the host, the “Memory Weight” of the VMs are evaluated in a relative manner and the VMs with lower relative “Memory Weight” will be penalized more than the ones with higher “Memory Weight”.   Dynamic Memory Configuration   Based on these concepts “Startup Memory”, “Maximum Memory”, “Memory Buffer” and “Memory Weight” can be configured as shown below in Windows Server 2008 R2 SP1 Hyper-V Manager. Memory Demand is automatically calculated by Dynamic Memory once VMs start running.     Dynamic Memory Monitoring    In Windows Server 2008 R2 SP1, Hyper-V Manager displays the memory status of VMs in the following three columns:         ·         Assigned Memory represents the current physical memory assigned to the VM. In regular conditions this will be equal to the sum of “Memory Demand” and “Memory Buffer” assigned to the VM. When there is not enough memory on the host, this value can go below the Memory Demand determined for the VM. ·         Memory Demand displays the current “Memory Demand” determined for the VM. ·         Memory Status displays the current memory status of the VM. This column can represent three values for a VM: o   OK: In this condition the VM is assigned the total of Memory Demand and Memory Buffer it needs. o   Low: In this condition the VM is assigned all the Memory Demand and a certain percentage of the Memory Buffer it needs. o   Warning: In this condition the VM is assigned a lower memory than its Memory Demand. When VMs are running in this condition, it’s likely that they will exhibit performance problems due to internal paging happening in the VM.    So far so good! But how does it work with SQL Server?   SQL Server is aggressive in terms of memory usage for good reasons. This raises the question: How do SQL Server and Dynamic Memory work together? To understand the full story, we’ll first need to understand how SQL Server Memory Management works. This will be covered in our second post in “SQL and Dynamic Memory” series. Meanwhile if you want to dive deeper into Dynamic Memory you can check the below posts from the Windows Virtualization Team Blog:   http://blogs.technet.com/virtualization/archive/2010/03/18/dynamic-memory-coming-to-hyper-v.aspx   http://blogs.technet.com/virtualization/archive/2010/03/25/dynamic-memory-coming-to-hyper-v-part-2.aspx   http://blogs.technet.com/virtualization/archive/2010/04/07/dynamic-memory-coming-to-hyper-v-part-3.aspx   http://blogs.technet.com/b/virtualization/archive/2010/04/21/dynamic-memory-coming-to-hyper-v-part-4.aspx   http://blogs.technet.com/b/virtualization/archive/2010/05/20/dynamic-memory-coming-to-hyper-v-part-5.aspx   http://blogs.technet.com/b/virtualization/archive/2010/07/12/dynamic-memory-coming-to-hyper-v-part-6.aspx   - Serdar Sutay   Originally posted at http://blogs.msdn.com/b/sqlosteam/

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