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• How to mange big amount users at server side?

  - by Rami

  I built a social android application in which users can see other users around them by gps location. at the beginning thing went well as i had low number of users, But now that I have increasing number of users (about 1500 +100 every day) I revealed a major problem in my design. In my Google App Engine servlet I have static HashMap that holding all the users profiles objects, currenty 1500 and this number will increase as more users register. Why I'm doing it Every user that requesting for the users around him compares his gps with other users and check if they are in his 10km radius, this happens every 5 min on average. That is why I can't get the users from db every time because GAE read/write operation quota will tare me apart. The problem with this desgin is As the number of users increased the Hashmap turns to null every 4-6 hours, I thing that this time is getting shorten but I'm not sure. I'm fixing this by reloading the users from the db every time I detect that it became null, But this causes DOS to my users for 30 sec, So I'm looking for better solution. I'm guessing that it happens because the size of the hashmap, Am I right? I have been advised to use spatial database, but that mean that I can't work with GAE any more and that mean that I need to build my big server all over again and lose my existing DB. Is there something I can do with the existing tools? Thanks.

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• OpenGL ES rotate texture

  - by 0xSina

  I just got started with OpenGL ES... I have a fragment: const char * sFragment = _STRINGIFY( varying highp vec2 coordinate; precision mediump float; uniform vec4 maskC; uniform float threshold; uniform sampler2D videoframe; uniform sampler2D videosprite; uniform vec4 mask; uniform vec4 maskB; uniform int recording; vec3 normalize(vec3 color, float meanr) { return color*vec3(0.75 + meanr, 1., 1. - meanr); } void main() { float d; float dB; float dC; float meanr; float meanrB; float meanrC; float minD; vec4 pixelColor; vec4 spriteColor; pixelColor = texture2D(videoframe, coordinate); spriteColor = texture2D(videosprite, coordinate); meanr = (pixelColor.r + mask.r)/8.; meanrB = (pixelColor.r + maskB.r)/8.; meanrC = (pixelColor.r + maskC.r)/8.; d = distance(normalize(pixelColor.rgb, meanr), normalize(mask.rgb, meanr)); dB = distance(normalize(pixelColor.rgb, meanrB), normalize(maskB.rgb, meanrB)); dC = distance(normalize(pixelColor.rgb, meanrC), normalize(maskC.rgb, meanrC)); minD = min(d, dB); minD = min(minD, dC); gl_FragColor = spriteColor; if (minD > threshold) { gl_FragColor = pixelColor; } } Now, depending on wether recording is 0 or 1, I want to rotate uniform sampler2D videosprite 180 degrees (reflection in x-axis, flip vertically). How can I do that? I found the function glRotatef(), but how do i specify that I want to rotate video sprite and not videoframe? Thanks

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• How to Generate a Create Table DDL Script Along With Its Related Tables

  - by Compudicted

  Have you ever wondered when creating table diagrams in SQL Server Management Studio (SSMS) how slickly you can add related tables to it by just right-clicking on the interesting table name? Have you also ever needed to script those related tables including the master one? And you discovered you have dozens of related tables? Or may be no SSMS at your disposal? That was me one day. Well, creativity to the rescue! I Binged and Googled around until I found more or less what I wanted, but it was all involving T-SQL, yeah, a long and convoluted CROSS APPLYs, then I saw a PowerShell solution that I quickly adopted to my needs (I am not referencing any particular author because it was a mashup): 1: ########################################################################################################### 2: # Created by: Arthur Zubarev on Oct 14, 2012 # 3: # Synopsys: Generate file containing the root table CREATE (DDL) script along with all its related tables # 4: ########################################################################################################### 5:   6: [System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO') | out-null 7:   8: $RootTableName = "TableName" # The table name, no schema name needed 9:   10: $srv = new-Object Microsoft.SqlServer.Management.Smo.Server("TargetSQLServerName") 11: $conContext = $srv.ConnectionContext 12: $conContext.LoginSecure = $True 13: # In case the integrated security is not used uncomment below 14: #$conContext.Login = "sa" 15: #$conContext.Password = "sapassword" 16: $db = New-Object Microsoft.SqlServer.Management.Smo.Database 17: $db = $srv.Databases.Item("TargetDatabase") 18:   19: $scrp = New-Object Microsoft.SqlServer.Management.Smo.Scripter($srv) 20: $scrp.Options.NoFileGroup = $True 21: $scrp.Options.AppendToFile = $False 22: $scrp.Options.ClusteredIndexes = $False 23: $scrp.Options.DriAll = $False 24: $scrp.Options.ScriptDrops = $False 25: $scrp.Options.IncludeHeaders = $True 26: $scrp.Options.ToFileOnly = $True 27: $scrp.Options.Indexes = $False 28: $scrp.Options.WithDependencies = $True 29: $scrp.Options.FileName = 'C:\TEMP\TargetFileName.SQL' 30:   31: $smoObjects = New-Object Microsoft.SqlServer.Management.Smo.UrnCollection 32: Foreach ($tb in $db.Tables) 33: { 34: Write-Host -foregroundcolor yellow "Table name being processed" $tb.Name 35: 36: If ($tb.IsSystemObject -eq $FALSE -and $tb.Name -eq $RootTableName) # feel free to customize the selection condition 37: { 38: Write-Host -foregroundcolor magenta $tb.Name "table and its related tables added to be scripted." 39: $smoObjects.Add($tb.Urn) 40: } 41: } 42:   43: # The actual act of scripting 44: $sc = $scrp.Script($smoObjects) 45:   46: Write-host -foregroundcolor green $RootTableName "and its related tables have been scripted to the target file." Enjoy!

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• Oracle NoSQL Database: Cleaner Performance

  - by Charles Lamb

  In an earlier post I noted that Berkeley DB Java Edition cleaner performance had improved significantly in release 5.x. From an Oracle NoSQL Database point of view, this is important because Berkeley DB Java Edition is the core storage engine for Oracle NoSQL Database. Many contemporary NoSQL Databases utilize log based (i.e. append-only) storage systems and it is well-understood that these architectures also require a "cleaning" or "compaction" mechanism (effectively a garbage collector) to free up unused space. 10 years ago when we set out to write a new Berkeley DB storage architecture for the BDB Java Edition ("JE") we knew that the corresponding compaction mechanism would take years to perfect. "Cleaning", or GC, is a hard problem to solve and it has taken all of those years of experience, bug fixes, tuning exercises, user deployment, and user feedback to bring it to the mature point it is at today. Reports like Vinoth Chandar's where he observes a 20x improvement validate the maturity of JE's cleaner. Cleaner performance has a direct impact on predictability and throughput in Oracle NoSQL Database. A cleaner that is too aggressive will consume too many resources and negatively affect system throughput. A cleaner that is not aggressive enough will allow the disk storage to become inefficient over time. It has to Work well out of the box, and Needs to be configurable so that customers can tune it for their specific workloads and requirements. The JE Cleaner has been field tested in production for many years managing instances with hundreds of GBs to TBs of data. The maturity of the cleaner and the entire underlying JE storage system is one of the key advantages that Oracle NoSQL Database brings to the table -- we haven't had to reinvent the wheel.

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• How to manage many mobile device users at server side?

  - by Rami

  I built a social Android application in which users can see other users around them by GPS location. At the beginning thing went well as I had low number of users, but now that I have increasing number of users (about 1500 +100 every day) it has revealed a major problem in my design. In my Google App Engine servlet I have static HashMap that holds all the users profiles objects, currently 1500 and this number will increase as more users register. Why I'm doing it? Every user that requests for the users around him compares his GPS with other users and checks if they are in his 10km radius. This happens every five minutes on average. Consequently, I can't get the users from db every time because GAE read/write operation quota will tear me apart. The problem with this design is? As the number of users increases, the Hashmap turns to null every 4-6 hours, I think that this time is getting shorter, but I'm not sure. I'm fixing this by reloading the users from the db every time I detect that it becomes null, but this causes DOS to my users for 30 sec, so I'm looking for better solution. I'm guessing that it happens because the size of the hashmap. Am I right? I have been advised to use a spatial database, but that means that I can't work with GAE any more and it means that I need to build my big server all over again and lose my existing DB. Is there something I can do with the existing tools? Thanks.

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• What is the disadvantage of using abstract class as a database connectivity in zend framework 2 instead of service locator

  - by arslaan ejaz

  If I use database by creating adapter with drivers, initialize it in some abstract class and extend that abstract class to required model. Then use simple query statement. Like this: namespace My-Model\Model\DB; abstract class MysqliDB { protected $adapter; public function __construct(){ $this->adapter = new \Zend\Db\Adapter\Adapter(array( 'driver' => 'Mysqli', 'database' => 'my-database', 'username' => 'root', 'password' => '' )); } } And use abstract class of database like this in my models: class States extends DB\MysqliDB{ public function __construct(){ parent::__construct(); } protected $states = array(); public function select_all_states(){ $data = $this->adapter->query('select * from states'); foreach ($data->execute() as $row){ $this->states[] = $row; } return $this->states; } } I am new to zend framework, before i have experience of working in YII and Codeigniter. I like the object oriented in zend so i want to use it like this. And don't want to use it through service locater something like this: public function getServiceConfig(){ return array( 'factories' => array( 'addserver-mysqli' => new Model\MyAdapterFactory('addserver-mysqli'), 'loginDB' => function ($sm){ $adapter = $sm->get('addserver-mysqli'); return new LoginDB($adapter); } ) ); } In module. Am i Ok with this approach?

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• Implementing new required feature after software release

  - by TiagoBrenck

  Fake Scenario There is a software that was released 1 year ago. The software is to map and register all kind of animals on our planet. When the software was released, the client only needed to know the scientific name of the animal, a flag if it is in risk of extinction and a scale of dangerous(that is a fake software and specification, I don't want to discuss this here). There are already 100.000 animals records saved on DB. New Feature One year later, the client wants a new feature. It is really important to him to know the animals classes, and this is a required field. So he asks me to put a field to input the animal class, and this field is required. Or maybe where this animal was discovered. Problem I have already 100.000 recorded animals without a class or where it was discovered, but I need to insert a new column to storage this information and this column can't be null. I don't have a default value for this situation (there isn't a default animal class or where it was discovered). I don't want to keep the requirement rule only on my software, my DB must have this requirement too(I like to keep business rules on DB too). What are the alternatives to solve this situation? I am on a situation that this new feature cannot be previewed or reviewed for the existing records. The time already passed and I can't go back on time to get it

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• Are Vala and desktopcouch ready?

  - by pavolzetor

  Hi, I have started writting rss reader in Vala, but I don't know, what database system should I use, I cannot connect to couchdb and sqlite works fine, but I would like use couchdb because of ubuntu one. I have natty with latest updates public CouchDB.Session session; public CouchDB.Database db; public string feed_table = "feed"; public string item_table = "item"; public struct field { string name; string val; } // constructor public Database() { try { this.session = new CouchDB.Session(); } catch (Error e) { stderr.printf ("%s a\n", e.message); } try { this.db = new CouchDB.Database (this.session, "test"); } catch (Error e) { stderr.printf ("%s a\n", e.message); } try { this.session.get_database_info("test"); } catch (Error e) { stderr.printf ("%s aa\n", e.message); } try { var newdoc = new CouchDB.Document (); newdoc.set_boolean_field ("awesome", true); newdoc.set_string_field ("phone", "555-VALA"); newdoc.set_double_field ("pi", 3.14159); newdoc.set_int_field ("meaning_of_life", 42); this.db.put_document (newdoc); // store document } catch (Error e) { stderr.printf ("%s aaa\n", e.message); } reports $ ./xml_parser rss.xmlCannot connect to destination (127.0.0.1) aa Cannot connect to destination (127.0.0.1) aaa

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• Setting up a LAMP VM server for Development and Testing?

  - by TdotThomas

  Info: I would like to set up a VM server on my local computer which will serve pages in the exact same way as my current hosting (but only to me on my local computer). I currently pay a big web hosting company to host my website & web store and they are doing a great job, but I would like to be able to work on my Web site and its corresponding MySQL DB, HTML, and PHP code without being at risk of messing something completely up on the live servers. My current plan of action: Set up a VM webserver with Debian, MySQL, PHP, Apache. Copy web store (PHP/HTML) code to VM server. Copy my current MySQL databases from my hosting provider and install on VM server. Modify and test new features on VM server. Upload MySQL DB and HTML/PHP code back to web host's server where it should work as before but with new modifications. Questions: Now I'm pretty sure I have steps one and two down correctly but I can't for the life of me figure out how to proceed next, so here are my questions. I have my /etc/host file set up so www.MySite.test redirects to the IP address of the local VM webserver. Once I import my PHP/HTML files and MySQL file whats the best way to navigate around the fact that all of my files and DBs will reference www.MySite.com. I can export my MySQL dbs but do I also have to export my MySQL users and passwords to access those db or are those coded into my html/php code?

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• Thunderbird: "Could not initialize the application's security component" [closed]

  - by user unknown

  In Thunderbird, on startup, I get the error message: "Could not initialize the application's security component" The message continues to check permissions of the profile, and free disk space. df -h shows, that I have 19G free disk space. find . -not -perm -644 -not -perm -600 -ls shows: No file without rw-permissions for me. Before the error occured, thunderbird worked well. But I changed my main mail-account. I had two, let's call them A and B, and used mainly A, but now I wanted to deaktivate it, and receive and send automatically via the second. I Had problems moving the filters from inbox A to inbox B (missing copy-functionality). In the web, I found (mollazine) hints, to move key3.db, cert8.db and secmode.db out of the way, but it didn't work for me. Another hint was to uninstall Quickcam(?. sic!), but I don't have Quickcam. A third to recreate the profile, but I have subdirectories, filters, addressbook, groups - mails back to the year 2003. I don't want to risk the loss of data. The whole errormessage is: Could not initialize the application's security component. The most likely cause is problems with files in your application's profile directory. Please check that this directory has no read/write restrictions and your hard disk is not full or close to full. It is recommended that you exit the application and fix the problem. If you continue to use this session, you might see incorrect application behaviour when accessing security features. When I open the error-console, it is empty.

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• Oracle Database 12c ????????(?????)

  - by OTN-J Master

  Oracle Database 12c????????????? ?????????????????????????????????????¦ ??????????????? ????????? Oracle Database 12c????OTN??? Oracle Database 12c???? ¦ Oracle Database 12c???????????????? Oracle Database 12c ?????? (PDF)¦ Oracle Database 12c???????????? ??????????????? Oracle Database 12c (??????????????) "Oracle Database 12c???"??????????????????? ??????NEC???????????????? ???????????????????????¦ Oracle Database 12c??????????????????? ???????????Oracle Database 12c ????? (PC/????????????!) ????????????????????????????? ?????????????????! Oracle Database 12c???????? (@IT /Database Expert) ??????Oracle Database 12c????????·?????????????????? (EnterpriseZine/DB Online) ??????????!Oracle Database 12c???? (EnterpriseZine/DB Online) ¦ Oracle Database 12c?????????????????????? ??????????Oracle Database 12c ?????!  (EnterpriseZine/DB Online) ¦ Oracle Database 12c???????????? ????????? OTN???????????????????????????????????????????? ?????????/??????? ~????????????????12c??????????!~ Oracle Database 12c????????!???????????? ¦ Oracle Database 12c??????????????????? Oracle University?? Oracle Database 12c: ?????? ¦ Oracle Database 12c?????????????????????????? ?????????????????? ¦ Oracle Database 12c????????????????? ?????????????????????????????????????????(??)???????????????????????????OTN Community(??????)?????????OTN Community??? ¦ Oracle Database 12c???????????????? 12c????????????????????????OTN????????????????Twitter(@oracletechnetjp)???????????????????????! ????????????????????????????Oracle Database 12c???????????????(?8???????????&??????????)????????

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• Oracle Database Appliance:???????????1Box?????2????????!

  - by Yusuke.Yamamoto

  11?14????????·????????Oracle Database Appliance???????????????? ????????:????????Oracle Database Appliance??????????? Oracle Database Appliance ??? Oracle Database Appliance ??Oracle Database ?????????????????????????·??????????Oracle Database ??(1)??????(2)RAC One Node ??(3)Oracle RAC ?????????????????????? Oracle Real Application Clusters(RAC)|??????????? ??????Oracle Database 11gR2 Oracle Real Application Clusters One Node ??(1)?????DB?????????????1Box???????? Oracle Database Appliance ???Oracle Real Application Clusters(RAC) ????????????DB??????????????????(????2??????????????????????????????????????????)?1Box????4U???????????????????????? ??(2)?????DB????2???????? Oracle Database Appliance ???Oracle Appliance Manager ????????????????????????Oracle Appliance Manager ????????(7????)???????????(Oracle Database?Oracle Grid Infrastructure?Oracle Enterprise Manager??)?????????(????????????????)?????????????????????2??????? ???Oracle Database Appliance ???????????????????????·????????????? Oracle Appliance Manager:????????????:7??????????????????? ??(3)????????????:???CPU???????????????????? Oracle Database Appliance ????Pay-As-You-Grow(?????????????)???????????????·????????????????Oracle Database Enterprise Edition ???????2??~24????????????? ?????????????????Oracle Database Enterprise Edition ????????(??????????????????)??????????????? Oracle Database Appliance:???? ????????????????????????????????? Oracle Database Appliance:???? ?????? Oracle Database Appliance Oracle Database Appliance:?????? Oracle Database Appliance:?????(??) Oracle Database Appliance:3D?? ????????? Oracle Direct ????Oracle Appliance Manager ????????????????????

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• Oracle Direct ???????·????

  - by ???02

  Oracle Direct ???????·???????????????????????????????????????? ????????????????????????????????? ????????????????????? ???????????????????????????????????????ID??·??????????????????Oracle Database 11g?????!? Oracle Database 11g~???????~Oracle Database 11g???????????????????????·??·???????????????????????????????????????????????????????????????????????????????!!??(PDF) ??(WMV) ??(MP4)??????????!!??????~Oracle Database???~J-SOX?????????????Oracle?????????????????????????????????(PDF) ??(WMV) ??(MP4)??!!??????~OracleDatabase????~Oracle RDBMS ????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)????·???????????????·?????????????????·????????????????????????????????DB?OS?????????????????????????????????????????????????????????·????????????????????????????????????????????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)????????????????????????????????????????????????????????????????????????????????????????Oracle Data Masking?????????????????????????????????????????????????????????????????(PDF) ??(Flash)??????????! ?????????????Oracle DBA & Developer Days 2010??????????????! ??????????????????????????????????????????????DB???????????????????????(PDF) ??(WMV) ??(MP4)??????????????????????????????????????????????????????????????SQL????????????????????????????????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)?????????????????????????????????????????????????????????????????Oracle?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)???????!??????????????????????????????????·?????????????????????????????????????????????????????????????????????????????????????????????????!??(PDF) ??(WMV) ??(MP4)ID??·?????????????????????????!????ID?????????????????????????ID?????????????????????????????????????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)ID???????????!????DB?OS?????/??????????????????????????????????????????????????????????????????????????????????????????????????????????????OS?????/???????????????????????????(PDF) ??(WMV) ??(MP4)??????·????????PC????!???????????????????????????????????????????????????????????????????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)ID???????????????????????????????????!??ID·???????????????????ID·???????????????????????????????????????????????????????Oracle Identity Management 11g ?????????????????????????ID·?????????????????????11g ?????????????????????????????????????????????(PDF) ??(WMV) ??(MP4)????·???????????????????~????????????????????????????????????????????????????????????????????????????????????????????????????????·????????ID?????????????????????????????????????????????? ??ID/????????????????????(PDF)???????????????????????????????????~???????????????????????????????????????????IT??????????????????????·??????????????????????IT?????????????????????????????????????????????????????????????????IT ?????????????????????????????????????????????????(PDF)??????·????Sun??????! ??????·?????????????????????????·?????????????Sun Directory Server Enterprise Edition???OS??????????????????????????????13?????????????????????????????????????????????????????????????????????????????????????(PDF)Active Directory?????????????????????????Active Directory?????????????????????????????? ???????????????????????????????????!??(PDF)Active Directory?? ~??????~Active Directory?????????????????????????Active Directory?????????????????????????????? ???????????????????????????????????!??(PDF)Active Directory?? ~????????~Windows7??!Active Directory + Oracle ????????? ????? ???SAP?Notes?????????/??????????????Web??????????????????????????????????????????????????????????????????????????????????????????????????????????·????? Oracle Enterprise Single Sign-On Suite??????????(PDF) ?????? Oracle Direct

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• C#: BackgroundWorker cloning resources?

  - by Dav

  The problem I've been struggling with this partiular problem for two days now and just run out of ideas. A little... background: we have a WinForms app that needs to access a database, construct a list of related in-memory objects from that data, and then display on a DataGridView. Important point is that we first populate an app-wide cache (List), and then create a mirror of the cache local to the form on which the DGV lives (using List constructor param). Because fetching the data takes a good few seconds (DB sits on a LAN server) to load, we decided to use a BackgroundWorker, and only refresh the DGV once the data is loaded. However, it seems that doing the loading via a BGW results in some memory leak... or an error on my part. When loaded using a blocking method call, the app consumes about 30MB of RAM; with a BGW this jumps to 80MB! While it may not seem as much anyway, our clients are not too happy about it. Relevant code Form private void MyForm_Load(object sender, EventArgs e) { MyRepository.Instance.FinishedEvent += RefreshCache; } private void RefreshCache(object sender, EventArgs e) { dgvProducts.DataSource = new List<MyDataObj>(MyRepository.Products); } Repository private static List<MyDataObj> Products { get; set; } public event EventHandler ProductsLoaded; public void GetProductsSync() { List<MyDataObj> p; using (MyL2SDb db = new MyL2SDb(MyConfig.ConnectionString)) { p = db.PRODUCTS .Select(p => new MyDataObj {Id = p.ID, Description = p.DESCR}) .ToList(); } Products = p; // tell the form to refresh UI if (ProductsLoaded != null) ProductsLoaded(this, null); } public void GetProductsAsync() { using (BackgroundWorker myWorker = new BackgroundWorker()) { myWorker.DoWork += delegate { List<MyDataObj> p; using (MyL2SDb db = new MyL2SDb(MyConfig.ConnectionString)) { p = db.PRODUCTS .Select(p => new MyDataObj {Id = p.ID, Description = p.DESCR}) .ToList(); } Products = p; }; // tell the form to refresh UI when finished myWorker.RunWorkerCompleted += GetProductsCompleted; myWorker.RunWorkerAsync(); } } private void GetProductsCompleted(object sender, RunWorkerCompletedEventArgs e) { if (ProductsLoaded != null) ProductsLoaded(this, null); } End! GetProductsSync or GetProductsAsync are called on the main thread, not shown above. Could it be that the GarbageCollector just gets lost with two threads? Or is it the task manager that shows incorrect values? Will be greateful for any responses, suggestions, criticism.

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• SaaS Architecture Question from Newbie

  - by user226767

  I have developed a number of departmental client-server applications, and am now ready to begin working on moving one of these applications to a SaaS model. I have done some basic web development, but I'm a newbie when it comes to SaaS architectures. One of the first questions that comes to mind as I try to design the architecture is the question of single vs. multi tenancy. The pros and cons of each vary significantly depending on the type of application and scale required, so I'd like to describe my application and scale needs below, and hope others can comment on how I should get started with the architecture. The client-server application currently consists of a Firebird database and a Windows application. The database contains about 20 tables containing a few thousand records in 4 primary tables, and a few hundred records in various lookup and related tables. Although the number of records is small, the size can get large, as the database can contain large BLOBS. Each customer sets up their own database and has a handful of users within the organization connected to it. When I update the db schema, a new windows application is released, and it checks the db schema and then applies the updates as needed. For the SaaS application, I am designing for 100's (not 1000's or millions) of new customers per year. My first thought was to go with a multi tenancy model to make updates easy (shut down apply the updates to one database, and then start up). On the other hand, a single tenancy model would provide a means to roll updates out to a group of customers at a time, and spread the risk of data corruption - i.e. if something goes wrong with a database, it will impact one customer instead of all customers. With this idea, I was thinking of having a single web front-end which would connect to a single customer database upon login. Thus, when a new customer creates an account, a new database would be created (each customer would have their own db with multiple users as needed for the customer). In this model, a db update would require either a process to go through each db to apply schema changes, or a trigger upon logging in to initiate a schema update similar to the client-server model currently in use. Can anyone point me to information for similar applications which have been ported from client-server to SaaS? Or provide any pointers to consider? Basically I'm looking for architecture examples of taking a departmental application and making it available as a self service website for multiple customers. Thanks for any suggestions, resources, etc.

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• What are the benefits of using ORM over XML Serialization/Deserialization?

  - by Tequila Jinx

  I've been reading about NHibernate and Microsoft's Entity Framework to perform Object Relational Mapping against my data access layer. I'm interested in the benefits of having an established framework to perform ORM, but I'm curious as to the performance costs of using it against standard XML Serialization and Deserialization. Right now, I develop stored procedures in Oracle and SQL Server that use XML Types for either input or output parameters and return or shred XML depending on need. I use a custom database command object that uses generics to deserialize the XML results into a specified serializable class. By using a combination of generics, xml (de)serialization and Microsoft's DAAB, I've got a process that's fairly simple to develop against regardless of the data source. Moreover, since I exclusively use Stored Procedures to perform database operations, I'm mostly protected from changes in the data structure. Here's an over-simplified example of what I've been doing. static void main() { testXmlClass test = new test(1); test.Name = "Foo"; test.Save(); } // Example Serializable Class ------------------------------------------------ [XmlRootAttribute("test")] class testXmlClass() { [XmlElement(Name="id")] public int ID {set; get;} [XmlElement(Name="name")] public string Name {set; get;} //create an instance of the class loaded with data. public testXmlClass(int id) { GenericDBProvider db = new GenericDBProvider(); this = db.ExecuteSerializable("myGetByIDProcedure"); } //save the class to the database... public Save() { GenericDBProvider db = new GenericDBProvider(); db.AddInParameter("myInputParameter", DbType.XML, this); db.ExecuteSerializableNonQuery("mySaveProcedure"); } } // Database Handler ---------------------------------------------------------- class GenericDBProvider { public T ExecuteSerializable<T>(string commandText) where T : class { XmlSerializer xml = new XmlSerializer(typeof(T)); // connection and command code is assumed for the purposes of this example. // the final results basically just come down to... return xml.Deserialize(commandResults) as T; } public void ExecuteSerializableNonQuery(string commandText) { // once again, connection and command code is assumed... // basically, just execute the command along with the specified // parameters which have been serialized. } public void AddInParameter(string name, DbType type, object value) { StringWriter w = new StringWriter(); XmlSerializer x = new XmlSerializer(value.GetType()); //handle serialization for serializable classes. if (type == DbType.Xml && (value.GetType() != typeof(System.String))) { x.Serialize(w, value); w.Close(); // store serialized object in a DbParameterCollection accessible // to my other methods. } else { //handle all other parameter types } } } I'm starting a new project which will rely heavily on database operations. I'm very curious to know whether my current practices will be sustainable in a high-traffic situation and whether or not I should consider switching to NHibernate or Microsoft's Entity Framework to perform what essentially seems to boil down to the same thing I'm currently doing. I appreciate any advice you may have.

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• The question about the basics of LINQ to SQL

  - by Alex

  I just started learning LINQ to SQL, and so far I'm impressed with the easy of use and good performance. I used to think that when doing LINQ queries like from Customer in DB.Customers where Customer.Age > 30 select Customer LINQ gets all customers from the database ("SELECT * FROM Customers"), moves them to the Customers array and then makes a search in that Array using .NET methods. This is very inefficient, what if there are hundreds of thousands of customers in the database? Making such big SELECT queries would kill the web application. Now after experiencing how actually fast LINQ to SQL is, I start to suspect that when doing that query I just wrote, LINQ somehow converts it to a SQL Query string SELECT * FROM Customers WHERE Age > 30 And only when necessary it will run the query. So my question is: am I right? And when is the query actually run? The reason why I'm asking is not only because I want to understand how it works in order to build good optimized applications, but because I came across the following problem. I have 2 tables, one of them is Books, the other has information on how many books were sold on certain days. My goal is to select books that had at least 50 sales/day in past 10 days. It's done with this simple query: from Book in DB.Books where (from Sale in DB.Sales where Sale.SalesAmount >= 50 && Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID).Contains(Book.ID) select Book The point is, I have to use the checking part in several queries and I decided to create an array with IDs of all popular books: var popularBooksIDs = from Sale in DB.Sales where Sale.SalesAmount >= 50 && Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID; BUT when I try to do the query now: from Book in DB.Books where popularBooksIDs.Contains(Book.ID) select Book It doesn't work! That's why I think that we can't use thins kinds of shortcuts in LINQ to SQL queries, like we can't use them in real SQL. We have to create straightforward queries, am I right?

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• perl dancer: passing database info to template

  - by Bubnoff

  Following Dancer tutorial here: http://search.cpan.org/dist/Dancer/lib/Dancer/Tutorial.pod I'm using my own sqlite3 database with this schema CREATE TABLE if not exists location (location_code TEXT PRIMARY KEY, name TEXT, stations INTEGER); CREATE TABLE if not exists session (id INTEGER PRIMARY KEY, date TEXT, sessions INTEGER, location_code TEXT, FOREIGN KEY(location_code) REFERENCES location(location_code)); My dancer code ( helloWorld.pm ) for the database: package helloWorld; use Dancer; use DBI; use File::Spec; use File::Slurp; use Template; our $VERSION = '0.1'; set 'template' => 'template_toolkit'; set 'logger' => 'console'; my $base_dir = qq(/home/automation/scripts/Area51/perl/dancer); # database crap sub connect_db { my $db = qw(/home/automation/scripts/Area51/perl/dancer/sessions.sqlite); my $dbh = DBI->connect("dbi:SQLite:dbname=$db", "", "", { RaiseError => 1, AutoCommit => 1 }); return $dbh; } sub init_db { my $db = connect_db(); my $file = qq($base_dir/schema.sql); my $schema = read_file($file); $db->do($schema) or die $db->errstr; } get '/' => sub { my $branch_code = qq(BPT); my $dbh = connect_db(); my $sql = q(SELECT * FROM session); my $sth = $dbh->prepare($sql) or die $dbh->errstr; $sth->execute or die $dbh->errstr; my $key_field = q(id); template 'show_entries.tt', { 'branch' => $branch_code, 'data' => $sth->fetchall_hashref($key_field), }; }; init_db(); true; Tried the example template on the site, doesn't work. <% FOREACH id IN data.keys.nsort %> <li>Date is: <% data.$id.sessions %> </li> <% END %> Produces page but with no data. How do I troubleshoot this as no clues come up in the console/cli? Thanks Bubnoff

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• CI pagination, POST problem

  - by Gwood

  Okay, I am pretty new in CI and I am stuck on pagination. I am performing this pagination on a record set that is result of a query. Now everything seems to be working fine. But there’s some problem probably with the link. I am displaying 10 results per page. Now if the results are less than 10 then it’s fine. Or If I pull up the entire records in the table it works fine. But in case the result is more than 10 rows, then the first 10 is perfectly displayed, and when I click on the pagination link to get to the next page the next page displays the rest of the results from the query as well as, other records in the table. ??? I am confused.. Any help?? Here’s the model code I am using .... function getTeesLike($field,$param) { $this-db-like($field,$param); $this-db-limit(10, $this-uri-segment(3)); $query=$this-db-get(‘shirt’); if($query-num_rows()0){ return $query-result_array(); } } function getNumTeesfromQ($field,$param) { $this-db-like($field,$param); $query=$this-db-get(‘shirt’); return $query-num_rows(); } And here’s the controller code .... $KW=$this-input-post(‘searchstr’); $this-load-library(‘pagination’); $config[‘base_url’]=‘http://localhost/cit/index.php/tees/show/’; $config[‘total_rows’]=$this-T-getNumTeesfromQ(‘Title’,$KW); $config[‘per_page’]=‘10’; $this-pagination-initialize($config); $data[‘tees’]=$this-T-getTeesLike(‘Title’,$KW); $data[‘title’]=‘Displaying Tees data’; $data[‘header’]=‘Tees List’; $data[‘links’]=$this-pagination-create_links(); $this-load-view(‘tee_res’, $data); //What am I doing wrong here ???? Pls help ... I guess the problem is with the $KW=$this-input-post(‘searchstr’); .. Because if I hard code a value for $KW it works fine. May be I should use POST differently ..but how do I pass the value from the form without POSTING it , its CI so not GET ... ??????

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• openDatabase Hello World

  - by cf_PhillipSenn

  I'm trying to learn about openDatabase, and I think this I'm getting it to INSERT INTO TABLE1, but I can't verify that the SELECT * FROM TABLE1 is working. <html> <head> <script src="http://www.google.com/jsapi"></script> <script type="text/javascript"> google.load("jquery", "1"); </script> <script type="text/javascript"> var db; $(function(){ db = openDatabase('HelloWorld'); db.transaction( function(transaction) { transaction.executeSql( 'CREATE TABLE IF NOT EXISTS Table1 ' + ' (TableID INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, ' + ' Field1 TEXT NOT NULL );' ); } ); db.transaction( function(transaction) { transaction.executeSql( 'SELECT * FROM Table1;',function (transaction, result) { for (var i=0; i < result.rows.length; i++) { alert('1'); $('body').append(result.rows.item(i)); } }, errorHandler ); } ); $('form').submit(function() { var xxx = $('#xxx').val(); db.transaction( function(transaction) { transaction.executeSql( 'INSERT INTO Table1 (Field1) VALUES (?);', [xxx], function(){ alert('Saved!'); }, errorHandler ); } ); return false; }); }); function errorHandler(transaction, error) { alert('Oops. Error was '+error.message+' (Code '+error.code+')'); transaction.executeSql('INSERT INTO errors (code, message) VALUES (?, ?);', [error.code, error.message]); return false; } </script> </head> <body> <form method="post"> <input name="xxx" id="xxx" /> <p> <input type="submit" name="OK" /> </p> <a href="http://www.google.com">Cancel</a> </form> </body> </html>

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• Help With LINQ: Mixed Joins and Specifying Default Values

  - by Corey O.

  I am trying to figure out how to do a mixed-join in LINQ with specific access to 2 LINQ objects. Here is an example of how the actual TSQL query might look: SELECT * FROM [User] AS [a] INNER JOIN [GroupUser] AS [b] ON [a].[UserID] = [b].[UserID] INNER JOIN [Group] AS [c] ON [b].[GroupID] = [c].[GroupID] LEFT JOIN [GroupEntries] AS [d] ON [a].[GroupID] = [d].[GroupID] WHERE [a].[UserID] = @UserID At the end, basically what I would like is an enumerable object full of GroupEntry objects. What am interested is the last two tables/objects in this query. I will be displaying Groups as a group header, and all of the Entries underneath their group heading. If there are no entries for a group, I still want to see that group as a header without any entries. Here's what I have so far: So from that I'd like to make a function: public void DisplayEntriesByUser(int user_id) { MyDataContext db = new MyDataContext(); IEnumberable<GroupEntries> entries = ( from user in db.Users where user.UserID == user_id join group_user in db.GroupUsers on user.UserID = group_user.UserID into a from join1 in a join group in db.Groups on join1.GroupID equals group.GroupID into b from join2 in b join entry in db.Entries.DefaultIfEmpty() on join2.GroupID equals entry.GroupID select entry ); Group last_group_id = 0; foreach(GroupEntry entry in entries) { if (last_group_id == 0 || entry.GroupID != last_group_id) { last_group_id = entry.GroupID; System.Console.WriteLine("---{0}---", entry.Group.GroupName.ToString().ToUpper()); } if (entry.EntryID) { System.Console.WriteLine(" {0}: {1}", entry.Title, entry.Text); } } } The example above does not work quite as expected. There are 2 problems that I have not been able to solve: I still seem to be getting an INNER JOIN instead of a LEFT JOIN on the last join. I am not getting any empty results, so groups without entries do not appear. I need to figure out a way so that I can fill in the default values for blank sets of entries. That is, if there is a group without an entry, I would like to have a mostly blank entry returned, except that I'd want the EntryID to be null or 0, the GroupID to be that of of the empty group that it represents, and I'd need a handle on the entry.Group object (i.e. it's parent, empty Group object). Any help on this would be greatly appreciated. Note: Table names and real-world representation were derived purely for this example, but their relations simplify what I'm trying to do.

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• Having trouble doing an Update with a Linq to Sql object

  - by Pure.Krome

  Hi folks, i've got a simple linq to sql object. I grab it from the database and change a field then save. No rows have been updated. :( When I check the full Sql code that is sent over the wire, I notice that it does an update to the row, not via the primary key but on all the fields via the where clause. Is this normal? I would have thought that it would be easy to update the field(s) with the where clause linking on the Primary Key, instead of where'ing (is that a word :P) on each field. here's the code... using (MyDatabase db = new MyDatabase()) { var boardPost = (from bp in db.BoardPosts where bp.BoardPostId == boardPostId select bp).SingleOrDefault(); if (boardPost != null && boardPost.BoardPostId > 0) { boardPost.ListId = listId; // This changes the value from 0 to 'x' db.SubmitChanges(); } } and here's some sample sql.. exec sp_executesql N'UPDATE [dbo].[BoardPost] SET [ListId] = @p6 WHERE ([BoardPostId] = @p0) AND .... <snip the other fields>',N'@p0 int,@p1 int,@p2 nvarchar(9),@p3 nvarchar(10),@p4 int,@p5 datetime,@p6 int',@p0=1276,@p1=212787,@p2=N'ttreterte',@p3=N'ttreterte3',@p4=1,@p5='2009-09-25 12:32:12.7200000',@p6=72 Now, i know there's a datetime field in this update .. and when i checked the DB it's value was/is '2009-09-25 12:32:12.720' (less zero's, than above) .. so i'm not sure if that is messing up the where clause condition... but still! should it do a where clause on the PK's .. if anything .. for speed! Yes / no ? UPDATE After reading nitzmahone's reply, I then tried playing around with the optimistic concurrency on some values, and it still didn't work :( So then I started some new stuff ... with the optimistic concurrency happening, it includes a where clause on the field it's trying to update. When that happens, it doesn't work. so.. in the above sql, the where clause looks like this ... WHERE ([BoardPostId] = @p0) AND ([ListId] IS NULL) AND ... <rest snipped>) This doesn't sound right! the value in the DB is null, before i do the update. but when i add the ListId value to the where clause (or more to the point, when L2S add's it because of the optomistic concurrecy), it fails to find/match the row. wtf?

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• codeIgniter: pass parameter to a select query from previous query

  - by krike

  I'm creating a little management tool for the browser game travian. So I select all the villages from the database and I want to display some content that's unique to each of the villages. But in order to query for those unique details I need to pass the id of the village. How should I do this? this is my code (controller): function members_area() { global $site_title; $this->load->model('membership_model'); if($this->membership_model->get_villages()) { $data['rows'] = $this->membership_model->get_villages(); $id = 1;//this should be dynamic, but how? if($this->membership_model->get_tasks($id)): $data['tasks'] = $this->membership_model->get_tasks($id); endif; } $data['title'] = $site_title." | Your account"; $data['main_content'] = 'account'; $this->load->view('template', $data); } and this is the 2 functions I'm using in the model: function get_villages() { $q = $this->db->get('villages'); if($q->num_rows() > 0) { foreach ($q->result() as $row) { $data[] = $row; } return $data; } } function get_tasks($id) { $this->db->select('name'); $this->db->from('tasks'); $this->db->where('villageid', $id); $q = $this->db->get(); if($q->num_rows() > 0) { foreach ($q->result() as $task) { $data[] = $task; } return $data; } } and of course the view: <?php foreach($rows as $r) : ?> <div class="village"> <h3><?php echo $r->name; ?></h3> <ul> <?php foreach($tasks as $task): ?> <li><?php echo $task->name; ?></li> <?php endforeach; ?> </ul> <?php echo anchor('site/add_village/'.$r->id.'', '+ add new task'); ?> </div> <?php endforeach; ?> ps: please do not remove the comment in the first block of code!

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• MySQL Database Query - Codeigniter

  - by user2450349

  I am building an application with Codeigniter and need some help with a DB query. I have a table called users with the following fields: user_id, user_name, user_password, user_email, user_role, user_manager_id In my app, I pull all records from the user table using the following: function get_clients() { $this->db->select('*'); $this->db->where('user_role', 'client'); $this->db->order_by("user_name", "Asc"); $query = $this->db->get("users"); return $query->result_array(); } This works as expected, however when I display the results in the view, I also want to display a new column called Manager which will display the managers user_name field. The user_manager_id is the id of the user from the same table. Im guessing you can create an outer join on the same table but not sure. In the view, I am displaying the returned info as follows: <table class="table table-striped" id="zero-configuration"> <thead> <tr> <th>Name</th> <th>Email</th> <th>Manager</th> </tr> </thead> <tbody> <?php foreach($clients as $row) { ?> <tr> <td><?php echo $row['user_name']; ?> (<?php echo $row['user_username']; ?>)</td> <td><?php echo $row['user_email']; ?></td> <td><?php echo $row['???']; ?></td> </tr> <?php } ?> </tbody> </table> Any idea of how I can form the query and display the manager name is the view? Example: user_id user_name user_password user_email user_role user_manager_id 1 Ollie adjjk34jcd [email protected] client null 2 James djklsdfsdjk [email protected] client 1 When i query the database, i want to display results like this: Ollie [email protected] James [email protected] Ollie

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• Delete duplicate rows, do not preserve one row

  - by Radley

  I need a query that goes through each entry in a database, checks if a single value is duplicated elsewhere in the database, and if it is - deletes both entries (or all, if more than two). Problem is the entries are URLs, up to 255 characters, with no way of identifying the row. Some existing answers on Stackoverflow do not work for me due to performance limitations, or they use uniqueid which obviously won't work when dealing with a string. Long Version: I have two databases containing URLs (and only URLs). One database has around 3,000 urls and the other around 1,000. However, a large majority of the 1,000 urls were taken from the 3,000 url database. I need to merge the 1,000 into the 3,000 as new entries only. For this, I made a third database with combined URLs from both tables, about 4,000 entries. I need to find all duplicate entries in this database and delete them (Both of them, without leaving either). I have followed the query of a few examples on this site, but whenever I try to delete both entries it ends up deleting all the entries, or giving sql errors. Alternatively: I have two databases, each containing the separate database. I need to check each row from one database against the other to find any that aren't duplicates, and then add those to a third database. Edit: I've got my own PHP solution which is pretty hacky, but works. I cannot answer my own question for 8 hours because I'm new, so here it is for now: I went with a PHP script to accomplish this, as I'm more familiar with PHP than MySQL. This generates a simple list of urls that only exist in the target database, but not both. If you have more than 7,000 entries to parse this may take awhile, and you will need to copy/paste the results into a text file or expand the script to store them back into a database. I'm just doing it manually to save time. Note: Uses MeekroDB <pre> <?php require('meekrodb.2.1.class.php'); DB::$user = 'root'; DB::$password = ''; DB::$dbName = 'testdb'; $all = DB::query('SELECT * FROM old_urls LIMIT 7000'); foreach($all as $row) { $test = DB::query('SELECT url FROM new_urls WHERE url=%s', $row['url']); if (!is_array($test)) { echo $row['url'] . "\n"; }else{ if (count($test) == 0) { echo $row['url'] . "\n"; } } } ?> </pre>

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