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  • cannot find table or object

    - by jeni
    hi all, Am running asp.net,c# application with sql server 2005. I got some problems with database tables.I got an inconsistency errors in some tables.I tried to run the below dbcc command to remove the inconsistent datas; DBCC CHECKTABLE ('Customer',repair_allow_data_loss) WITH ALL_ERRORMSG At first i run DBCC CHECKTABLE ('Customer') it is working.but now it is not working, i got an error as Cannot find a table or object with the name "Customer". Check the system catalog. Is my commands wrong.

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  • When to unload graphics object from main memory?

    - by piotrek
    I writing my resource mangaer, and I consider about how it can work for graphics objects (like textures, meshes). I think about this : I want to load texture (in pseudocode): Texture t = resMgr.GetTex("image.png"); and GetTex make something like this: load texture from disk to main memory create texture object (load it to gpu memory) unload texture from main memory I consider about 3 step, does game engines that you know unload meshes/textures after load them into gpu memory ?

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  • Should the main game object be static in c++

    - by Som_kun
    I am creating a 2d platformer using SDL and I was thinking that my game object could be static, but I wasn't sure if this was a good idea. The pros (that I can see): Accessing settings options (such as screen size and keyboard bindings) would be easier accessed There should only ever be one main game loop, so this makes sure for me. The cons: From what I've heard, static classes in C++ are a bear to work with I've read that this may cause problems later in development (things don't work right or can't be used properly

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  • The Sequence Object in SQL Server 2012

    The Sequence Object is one of the many exciting new features introduced in SQL Server 2012. Learn what this new feature can do for you and how you can use it. What are your servers really trying to tell you? Find out with new SQL Monitor 3.0, an easy-to-use tool built for no-nonsense database professionals.For effortless insights into SQL Server, download a free trial today.

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  • use of EntityManagerFactory causing duplicate primary key exceptions

    - by bradd
    Hey guys, my goal is create an EntityManager using properties dependent on which database is in use. I've seen something like this done in all my Google searches(I made the code more basic for the purpose of this question): @PersistenceUnit private EntityManagerFactory emf; private EntityManager em; private Properties props; @PostConstruct public void createEntityManager(){ //if oracle set oracle properties else set postgres properties emf = Persistence.createEntityManagerFactory("app-x"); em = emf.createEntityManager(props); } This works and I can load Oracle or Postgres properties successfully and I can Select from either database. HOWEVER, I am running into issues when doing INSERT statements. Whenever an INSERT is done I get a duplicate primary key exception.. every time! Can anyone shed some light on why this may be happening? Thanks -Brad

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  • OpenJPA - not flushing before queries

    - by Ales
    hi all, how can i set openjpa to flush before query. When i change some values in database i want to propagate these changes into application. I tried this settings in persistence.xml: <property name="openjpa.FlushBeforeQueries" value="true" /> <property name="openjpa.IgnoreChanges" value="false"/> false/true - same behavior to my case <property name="openjpa.DataCache" value="false"/> <property name="openjpa.RemoteCommitProvider" value="sjvm"/> <property name="openjpa.ConnectionRetainMode" value="always"/> <property name="openjpa.QueryCache" value="false"/> Any idea? Thanks

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  • Use of Java constructors in persistent entities

    - by Mr Morgan
    Hello I'm new to JPA and using persistence in Java anyway and I have two questions I can't quite work out: I have generated tags as: @JoinColumn(name = "UserName", referencedColumnName = "UserName") @ManyToOne(optional = false) private User userName; @JoinColumn(name = "DatasetNo", referencedColumnName = "DatasetNo") @ManyToOne(optional = false) private Dataset datasetNo; But in one of the constructors for the class, no reference is made to columns UserName or DatasetNo whereas all other columns in the class are referenced in the constructor. Can anyone tell me why this is? Both columns UserName and DatasetNo are 'foreign keys' on the entity Visualisation which corresponds to a database table of the same name. I can't quite work out the ORM. And when using entity classes, or POJO, is it better to have class variables like: private User userName; Where an instance of a class is specified or simply the key of that class instance like: private String userName; Thanks Mr Morgan.

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  • Persisting hashlib state

    - by anthony
    I'd like to create a hashlib instance, update() it, then persist its state in some way. Later, I'd like to recreate the object using this state data, and continue to update() it. Finally, I'd like to get the hexdigest() o the total cumulative run of data. State persistence has to survive across multiple runs. Example: import hashlib m = hashlib.sha1() m.update('one') m.update('two') # somehow, persist the state of m here #later, possibly in another process # recreate m from the persisted state m.update('three') m.update('four') print m.hexdigest() # at this point, m.hexdigest() should be equal to hashlib.sha1().update('onetwothreefour').hextdigets()

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  • Java framework "suggestion" for persisting the results from an Oracle 9i stored procedure using Apac

    - by chocksaway
    Hello, I am developing a Java servlet which calls an Oracle stored procedure. The stored procedure is likely to "grow" over time, and I have concerns the amount of time taken to "display the results on a web page". While I am at the implementation stage, I would like some suggestions of a Persistence framework which will work on Apache Tomcat 5.5? I see two approaches to persisting the database results. A scheduled database query every N minutes, or something which utilises triggers. Hibernate seems like the obvious answer, but I have never called stored procedures from Hibernate (HQL and Criteria). Is there a more appropriate framework which can be used? Thank you. cheers Miles.

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  • What is the fastest way to learn JPA ?

    - by Jacques René Mesrine
    I'm looking for the best resources (books, frameworks, tutorials) that will help me get up to speed with JPA. I've been happily using iBatis/JDBC for my persistence needs, so I need resources that will hopefully provide comparable functions on how to do things. e.g. how to I set the isolation level for each transaction ? I know there might be 10 books on the topic, so hopefully, your recommendation could narrow down to the best 2 books. Should I start with OpenJPA or are there other opensource JPA frameworks to use ? P.S. Do suggest if I should learn JPA2 or JPA1 ? My goal ultimately is to be able to write a Google App Engine app (which uses JPA1). Thanks Jacque

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  • How to keep Hibernate mapping use under control as requirements grow

    - by David Plumpton
    I've worked on a number of Java web apps where persistence is via Hibernate, and we start off with some central class (e.g. an insurance application) without any time being spent considering how to break things up into manageable chunks. Over time as features are added we add more mappings (rates, clients, addresses, etc.) and then amount of time spent saving and loading an insurance object and everything it connects to grows. In particular you get close to a go-live date and performance testing with larger amounts of data in each table is starting to demonstrate that it's all too slow. Obviously there are a number of ways that we could attempt to partition things up, e.g. map only the client classes for the client CRUD screens, etc., which would have been better to get in place earlier rather than trying to work it in at the end of the dev cycle. I'm just wondering if there are recommendations about ways to handle/mitigate this.

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  • Explicitly persist states in Workflow 4.0 rather than everything.

    - by jlafay
    I have ran into an issue with my SQL instance store attached to a WorkflowApplication that is running. When I exit my application I'm calling an Unload() on the WF app to persist it. I didn't think about it during design time, but it does makes sense, it's persisting an arg that was passed in to the WorkflowApplication constructor when instanced. When the application runs, everything in the workflow works as expected. When I call Unload() I get an unhandled exception that states that the arg is not serializable and needs [DataContractAttribute]. What's passed into the workflow is my applications custom logger object that I wrote so that the WF can log to disk in a uniform way that I prefer. How do I prevent the workflow app from persisting this one argument and persist everything else? I'm sure something can be done with extensions but I'm having a hard time finding info on them or finding persistence examples for my scenario.

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  • Determine which active directory object is referred to by GUID in a Directory Synchronization Error Report

    - by Michael Shimmins
    We have active directory syncronization setup between our on-premises AD server and Microsoft hosted Exchange (business productivity online services). I've started getting a daily error report, which details an error for a specific AD user, however it references it by GUID. I can't find any info on how to translate that object guid into something meaningful so I can find and fix the problem. The error is reported as: Error 005: Unable to set the alias for this object in Microsoft Online Services because either the primary SMTP address, the e-mail nickname, or the SAM account name in the local Active Directory contains an invalid character. in reference to the Object GUID: CN={8443cbb4-5199-49f0-9529-ce965430dca6} How can I translate that object guid into a friendly object name?

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  • Object array updates one instance repeatedly [on hold]

    - by MGN001
    I'm making a 2D shooter, and the player object holds an array of bullets that represent how many shots the player can have on screen at once. At least, this is what I'm trying for. What's happening is that each time any of the objects in the array is called, it seems to update a single object in memory. So, if I fire and then fire again, the object "starts over" from where I shot from and moves twice as fast. I've spent weeks trying to fix this and I've managed nothing. Hopefully another pair of eyes will see something I've missed. Player.cpp #include "Player.h" const int startLives = 3; const int maxHealth = 2; const float speed = 1; const int maxVelocity = 500; const int topBound = WINDOW_HEIGHT / 5 * 3; const int slowRate = 500; const int accRate = 1000; const int maxBullets = 5; const float spriteWidth = 99; const float spriteHeight = 75; const Vector2f startPosition = { (WINDOW_WIDTH / 2) - (spriteWidth / 2), (WINDOW_HEIGHT / 4 * 3) - (spriteHeight / 2) }; Bullet bullets[maxBullets]; Bullet * bulletPointers[maxBullets]; SDL_Texture * playerHealthy; SDL_Texture * playerDamaged; SDL_Texture * currentSprite; SDL_Rect * rect; Vector2f position; Vector2f velocity; int Health; int Lives; Player::Player() { rect = new SDL_Rect(); } Player::~Player() { SDL_DestroyTexture(playerHealthy); SDL_DestroyTexture(playerDamaged); SDL_DestroyTexture(currentSprite); rect = NULL; } void Player::Initialize(SDL_Renderer * renderer) { SDL_Surface * temp; temp = IMG_Load(".\\Sprites\\player.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } playerHealthy = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\playerDamaged.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } playerDamaged = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\laserGreen.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } SDL_Texture * bullet = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\laserGreenShot.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } SDL_Texture * explosion = SDL_CreateTextureFromSurface(renderer, temp); for (int i = 0; i < maxBullets; i++) { bullets[i].Initialize(renderer, bullet, explosion); bulletPointers[i] = NULL; } temp = NULL; rect->h = spriteHeight; rect->w = spriteWidth; Reset(); } void Player::Update(Input input, float deltaTime) { if (abs(velocity.x) < slowRate * deltaTime) { velocity.x = 0; } else if (velocity.x > 0) { velocity.x -= slowRate * deltaTime; } else if (velocity.x < 0) { velocity.x += slowRate * deltaTime; } if (abs(velocity.y) < slowRate * deltaTime) { velocity.y = 0; } if (velocity.y > 0) { velocity.y -= slowRate * deltaTime; } else if (velocity.y < 0) { velocity.y += slowRate * deltaTime; } if (Health <= 0) { --Lives; Spawn(); } velocity.x += UnitVector(input.InputNew.movement).x * accRate * deltaTime; velocity.y += UnitVector(input.InputNew.movement).y * accRate * deltaTime; if (Magnitude(velocity) > maxVelocity) { velocity.x = UnitVector(velocity).x * maxVelocity; velocity.y = UnitVector(velocity).y * maxVelocity; } position.x += velocity.x * deltaTime * speed; position.y += velocity.y * deltaTime * speed; if (input.InputNew.JumpLeft && !input.InputOld.JumpLeft) { position.x -= spriteWidth; } if (input.InputNew.JumpRight && !input.InputOld.JumpRight) { position.x += spriteWidth; } Boundaries(); rect->x = position.x; rect->y = position.y; if (input.InputNew.Fire && !input.InputOld.Fire) { Fire(); } for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] != NULL) { bullets[i].Update(deltaTime); if (bullets[i].getPosition().y < -33) { bulletPointers[i] = NULL; } } } } void Player::Draw(SDL_Renderer * renderer) { for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] != NULL) { bullets[i].Draw(renderer); } } SDL_RenderCopy(renderer, currentSprite, NULL, rect); } void Player::Spawn() { position = startPosition; Health = maxHealth; currentSprite = playerHealthy; rect->x = position.x; rect->y = position.y; } void Player::Boundaries() { if (position.x < 0) { position.x = 0; velocity.x *= -1; } else if (position.x > WINDOW_WIDTH - spriteWidth) { position.x = WINDOW_WIDTH - spriteWidth; velocity.x *= -1; } if (position.y < topBound) { position.y = topBound; velocity.y *= -1; } else if (position.y > WINDOW_HEIGHT - spriteHeight) { position.y = WINDOW_HEIGHT - spriteHeight; velocity.y *= -1; } } int Player::getLives() { return Lives; } void Player::Reset() { Lives = startLives; Spawn(); } void Player::Fire() { for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] == NULL) { bulletPointers[i] = &bullets[i]; bullets[i].Fire(position,velocity.x/2); break; } } } Bullet.cpp #include "Bullet.h" const int speed = 500; Vector2f bulletVelocity; float ExplosionMax = 0.5f; float ExplosionTimer; const Vector2f fireOffset = { 45.5f, 10.0f }; const Vector2f explosionOffset = { 23.5f, -27.0f }; const Vector2i bulletSize = { 9, 33 }; const Vector2i explosionSize = { 56, 54 }; Vector2f bulletPosition; SDL_Texture * bulletSprite; SDL_Texture * explosionSprite; SDL_Texture * bulletCurrentSprite; SDL_Rect * bulletRect; Bullet::Bullet() { } Bullet::~Bullet() { } void Bullet::Initialize(SDL_Renderer * renderer, SDL_Texture * bullet, SDL_Texture * explosion) { bulletSprite = bullet; explosionSprite = explosion; bulletRect = new SDL_Rect(); } void Bullet::Update(float deltaTime) { bulletPosition.y -= bulletVelocity.y * deltaTime; bulletPosition.x += bulletVelocity.x * deltaTime; bulletRect->x = static_cast<int>(bulletPosition.x); bulletRect->y = static_cast<int>(bulletPosition.y); } void Bullet::Draw(SDL_Renderer * renderer) { SDL_RenderCopy(renderer, bulletCurrentSprite, NULL, bulletRect); } void Bullet::Fire(Vector2f pos, float xSpeed) { bulletPosition.x = pos.x + fireOffset.x; bulletPosition.y = pos.y + fireOffset.y; bulletVelocity.x = xSpeed; bulletVelocity.y = speed; bulletCurrentSprite = bulletSprite; bulletRect->h = bulletSize.y; bulletRect->w = bulletSize.x; bulletRect->x = static_cast<int>(bulletPosition.x); bulletRect->y = static_cast<int>(bulletPosition.y); } Vector2f Bullet::getPosition() { return bulletPosition; } void Bullet::Hit() { bulletCurrentSprite = explosionSprite; bulletVelocity = { 0.0f, 0.0f }; ExplosionTimer = ExplosionMax; bulletPosition.x += explosionOffset.x; bulletPosition.y += explosionOffset.y; bulletRect->w = explosionSize.x; bulletRect->h = explosionSize.y; }

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  • The EXECUTE permission was denied on the object 'bam_Metadata_GetConfigurationXml'

    - by Andy Morrison
    We were seeing this exception on two servers when we tried to access the BAM Portal... after having to reconfigure the BAM Portal and Tools for reasons unrelated to the error: --- Log Name:      Application Source:        Bam Web Service Date:          2/18/2011 10:24:07 AM Event ID:      1534 Task Category: None Level:         Error Keywords:      Classic User:          N/A Computer:      yyyyyyyyyyyyyyyyyyyy Description: Current User: yy\yyyyyyyy EXCEPTION: Microsoft.BizTalk.Bam.Management.BamManagerException: Encountered error while executing command on SQL Server "yyyyyyyyyyyyyyy". ---> System.Data.SqlClient.SqlException: The EXECUTE permission was denied on the object 'bam_Metadata_GetConfigurationXml', database 'BAMPrimaryImport', schema 'dbo'.    at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)    at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)    at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)    at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)    at System.Data.SqlClient.SqlDataReader.ConsumeMetaData()    at System.Data.SqlClient.SqlDataReader.get_MetaData()    at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)    at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)    at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)    at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)    at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)    at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)    at Microsoft.BizTalk.Bam.Management.SqlHelper.ExecuteQuery(String cmdText, CommandType cmdType, Transaction transaction)    --- End of inner exception stack trace ---    at Microsoft.BizTalk.Bam.Management.SqlHelper.ExecuteQuery(String cmdText, CommandType cmdType, Transaction transaction)    at Microsoft.BizTalk.Bam.Management.BamConfigurationManager.GetConfigurationXmlFromPrimaryImportDb()    at Microsoft.BizTalk.Bam.Management.BamConfigurationManager..ctor(String piServer, String piDatabase, Int32 sqlHelperCmdTimeout, Boolean validateServerNames)    at Microsoft.BizTalk.Bam.Management.BamManager..ctor(String primaryImportServer, String primaryImportDatabase, Int32 sqlCmdTimeout, Boolean validateServerNames)    at Microsoft.BizTalk.Bam.Management.BamManager..ctor(String primaryImportServer, String primaryImportDatabase)    at Microsoft.BizTalk.Bam.WebServices.Utilities.FetchBamManager()    at Microsoft.BizTalk.Bam.WebServices.Management.BamManagementService.GetViewSummaryForCurrentUser() EXCEPTION: Microsoft.BizTalk.Bam.Management.BamManagerException: Encountered error while executing command on SQL Server "yyyyyyyyyyyyyyyyyy". ---&gt; System.Data.SqlClient.SqlException: The EXECUTE permission was denied on the object 'bam_Metadata_GetConfigurationXml', database 'BAMPrimaryImport', schema 'dbo'.    at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)    at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)    at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)    at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)    at System.Data.SqlClient.SqlDataReader.ConsumeMetaData()    at System.Data.SqlClient.SqlDataReader.get_MetaData()    at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)    at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)    at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)    at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)    at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)    at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)    at Microsoft.BizTalk.Bam.Management.SqlHelper.ExecuteQuery(String cmdText, CommandType cmdType, Transaction transaction)    --- End of inner exception stack trace ---    at Microsoft.BizTalk.Bam.Management.SqlHelper.ExecuteQuery(String cmdText, CommandType cmdType, Transaction transaction)    at Microsoft.BizTalk.Bam.Management.BamConfigurationManager.GetConfigurationXmlFromPrimaryImportDb()    at Microsoft.BizTalk.Bam.Management.BamConfigurationManager..ctor(String piServer, String piDatabase, Int32 sqlHelperCmdTimeout, Boolean validateServerNames)    at Microsoft.BizTalk.Bam.Management.BamManager..ctor(String primaryImportServer, String primaryImportDatabase, Int32 sqlCmdTimeout, Boolean validateServerNames)    at Microsoft.BizTalk.Bam.Management.BamManager..ctor(String primaryImportServer, String primaryImportDatabase)    at Microsoft.BizTalk.Bam.WebServices.Utilities.FetchBamManager()    at Microsoft.BizTalk.Bam.WebServices.Management.BamManagementService.GetViewSummaryForCurrentUser() --- We reconfigured the BAM Portal and Tools multiple times, trying to fix this issue, but kept getting the exception.  The fix was to add the BizTalk Server Administrators and BizTalk Application Users to the BAM_ManagementWS role in the BAMPrimaryImport database.  (Note that these two groups do not appear to be added to this role in a "clean" configuration. Thanks go to Ed at http://talentedmonkeys.wordpress.com/ for figuring out a solution.

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  • Storing simulation results in a persistent manner for Python?

    - by Az
    Background: I'm running multiple simuations on a set of data. For each session, I'm allocating projects to students. The difference between each session is that I'm randomising the order of the students such that all the students get a shot at being assigned a project they want. I was writing out some of the allocations in a spreadsheet (i.e. Excel) and it basically looked like this (tiny snapshot, actual table extends to a few thousand sessions, roughly 100 students). | | Session 1 | Session 2 | Session 3 | |----------|-----------|-----------|-----------| |Stu1 |Proj_AA |Proj_AB |Proj_AB | |----------|-----------|-----------|-----------| |Stu2 |Proj_AB |Proj_AA |Proj_AC | |----------|-----------|-----------|-----------| |Stu3 |Proj_AC |Proj_AC |Proj_AA | |----------|-----------|-----------|-----------| Now, the code that deals with the allocation currently stores a session in an object. The next time the allocation is run, the object is over-written. Thus what I'd really like to do is to store all the allocation results. This is important since I later need to derive from the data, information such as: which project Stu1 got assigned to the most or perhaps how popular Proj_AC was (how many times it was assigned / number of sessions). Question(s): What methods can I possibly use to basically store such session information persistently? Basically, each session output needs to add itself to the repository after ending and before beginning the next allocation cycle. One solution that was suggested by a friend was mapping these results to a relational database using SQLAlchemy. I kind of like the idea since this does give me an opportunity to delve into databases. Now the database structure I was recommended was: |----------|-----------|-----------| |Session |Student |Project | |----------|-----------|-----------| |1 |Stu1 |Proj_AA | |----------|-----------|-----------| |1 |Stu2 |Proj_AB | |----------|-----------|-----------| |1 |Stu3 |Proj_AC | |----------|-----------|-----------| |2 |Stu1 |Proj_AB | |----------|-----------|-----------| |2 |Stu2 |Proj_AA | |----------|-----------|-----------| |2 |Stu3 |Proj_AC | |----------|-----------|-----------| |3 |Stu1 |Proj_AB | |----------|-----------|-----------| |3 |Stu2 |Proj_AC | |----------|-----------|-----------| |3 |Stu3 |Proj_AA | |----------|-----------|-----------| Here, it was suggested that I make the Session and Student columns a composite key. That way I can access a specific record for a particular student for a particular session. Or I can merely get the entire allocation run for a particular session. Questions: Is the idea a good one? How does one implement and query a composite key using SQLAlchemy? What happens to the database if a particular student is not assigned a project (happens if all projects that he wants are taken)? In the code, if a student is not assigned a project, instead of a proj_id he simply gets None for that field/object. I apologise for asking multiple questions but since these are closely-related, I thought I'd ask them in the same space.

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  • How to properly test Hibernate length restriction?

    - by Cesar
    I have a POJO mapped with Hibernate for persistence. In my mapping I specify the following: <class name="ExpertiseArea"> <id name="id" type="string"> <generator class="assigned" /> </id> <version name="version" column="VERSION" unsaved-value="null" /> <property name="name" type="string" unique="true" not-null="true" length="100" /> ... </class> And I want to test that if I set a name longer than 100 characters, the change won't be persisted. I have a DAO where I save the entity with the following code: public T makePersistent(T entity){ transaction = getSession().beginTransaction(); transaction.begin(); try{ getSession().saveOrUpdate(entity); transaction.commit(); }catch(HibernateException e){ logger.debug(e.getMessage()); transaction.rollback(); } return entity; } Actually the code above is from a GenericDAO which all my DAOs inherit from. Then I created the following test: public void testNameLengthMustBe100orLess(){ ExpertiseArea ea = new ExpertiseArea( "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890" + "1234567890"); assertTrue("Name should be 100 characters long", ea.getName().length() == 100); ead.makePersistent(ea); List<ExpertiseArea> result = ead.findAll(); assertEquals("Size must be 1", result.size(),1); ea.setName(ea.getName()+"1234567890"); ead.makePersistent(ea); ExpertiseArea retrieved = ead.findById(ea.getId(), false); assertTrue("Both objects should be equal", retrieved.equals(ea)); assertTrue("Name should be 100 characters long", (retrieved.getName().length() == 100)); } The object is persisted ok. Then I set a name longer than 100 characters and try to save the changes, which fails: 14:12:14,608 INFO StringType:162 - could not bind value '12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890' to parameter: 2; data exception: string data, right truncation 14:12:14,611 WARN JDBCExceptionReporter:100 - SQL Error: -3401, SQLState: 22001 14:12:14,611 ERROR JDBCExceptionReporter:101 - data exception: string data, right truncation 14:12:14,614 ERROR AbstractFlushingEventListener:324 - Could not synchronize database state with session org.hibernate.exception.DataException: could not update: [com.exp.model.ExpertiseArea#33BA7E09-3A79-4C9D-888B-4263314076AF] //Stack trace 14:12:14,615 DEBUG GenericDAO:87 - could not update: [com.exp.model.ExpertiseArea#33BA7E09-3A79-4C9D-888B-4263314076AF] 14:12:14,616 DEBUG JDBCTransaction:186 - rollback 14:12:14,616 DEBUG JDBCTransaction:197 - rolled back JDBC Connection That's expected behavior. However when I retrieve the persisted object to check if its name is still 100 characters long, the test fails. The way I see it, the retrieved object should have a name that is 100 characters long, given that the attempted update failed. The last assertion fails because the name is 110 characters long now, as if the ea instance was indeed updated. What am I doing wrong here?

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  • ASP.NET MVC Session usage

    - by Ben
    Currently I am using ViewData or TempData for object persistance in my ASP.NET MVC application. However in a few cases where I am storing objects into ViewData through my base controller class, I am hitting the database on every request (when ViewData["whatever"] == null). It would be good to persist these into something with a longer lifespan, namely session. Similarly in an order processing pipeline, I don't want things like Order to be saved to the database on creation. I would rather populate the object in memory and then when the order gets to a certain state, save it. So it would seem that session is the best place for this? Or would you recommend that in the case of order, to retrieve the order from the database on each request, rather than using session? Thoughts, suggestions appreciated. Thanks Ben

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  • How do I do automatic data serialization of data objects in Haskell

    - by Adam Gent
    One of the huge benefits in languages that have some sort of reflection/introspecition is that objects can be automatically constructed from a variety of sources. For example in Java I can use the same objects for persisting to a db (with Hibernate) serializing to XML (with JAXB) or serializing to JSON (json-lib). You can do the same in Ruby and Python also usually following some simple rules for properties or annotations for Java. Thus I don't need lots "Domain Transfer Objects". I can concentrate on the domain I am working in. It seems in very strict FP like Haskell and Ocaml this is not possible. Particularly Haskell. The only thing I have seen is doing some sort of preprocessing or meta-programming (ocaml). Is it just accepted that you have to do all the transformations from the bottom upwards? In other words you have to do lot of boring work to turn a data type in haskell into JSON/XML/DB Row object and back again into a data object.

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  • Persisting sensitve data in asp.net, odd implementation

    - by rawsonstreet
    For reasons not in scope of this question I have implemented a .net project in an iframe which runs from a classic asp page. The classic asp site persisted a few sensitive values by hitting the db on each page. I have passed there variables as xml to the aspx page, now I need to make these values available on any page of this .net site. I've looked into the cache object but we are on a web farm so I am not sure it would work. Is there a way I can can instantiate an object in a base page class and have other pages inherit from the base page to access these values? What is the best way to persist these values? A few more points to consider the site runs in https mode and I cannot use session variables, and I would like to avoid cookies if possible..

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  • Data persistance with BufferedReader and PrintWriter?

    - by Nazgulled
    I have this simple application with a couple of classes which are all related. There's one, the main one, for which there is only one instance of. I need to save save and load that using a text stream. My instructor requirement is BufferedReader to load the stream and PrintWriter to save it. But is this even possible? To persist a data object/class with a text stream? I know how to do it with and object, using serialization. But I don't see how am I supposed to do it using text streams. Suggestions?

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  • Objective-C As A First OOP Language?

    - by Daniel Scocco
    I am just finishing the second semester of my CS degree. So far I learned C, all the fundamental algorithms and data structures (e.g., searching, sorting, linked lists, heaps, hash tables, trees, graphs, etc). Next year we'll start with OOP, using either Java or C++. Recently I got some ideas for some iPhone apps and got itchy to start working on them. However I heard some bad things about Objectice-C in the past, so I am wondering if learning it as my first OOP language could be a problem. Not to mention that I think it will be hard to find books/online courses that teach basic OOP concepts using Objective-C to illustrate the concepts (as opposed to books using Java or C++, which are plenty), so this could be another problem. In summary: should I start learning Objective-C and OOP concepts right now by my own, or wait one more semester until I learn Java/C++ at university and then jump into Objective-C? Update: For those interested in getting started with OOP via Objective-C I just found some nice tutorials inside Apple's Developer Library - http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/OOP_ObjC/Introduction/Introduction.html

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  • What Functional features are worth a little OOP confusion for the benefits they bring?

    - by bonomo
    After learning functional programming in Haskell and F#, the OOP paradigm seems ass-backwards with classes, interfaces, objects. Which aspects of FP can I bring to work that my co-workers can understand? Are any FP styles worth talking to my boss about retraining my team so that we can use them? Possible aspects of FP: Immutability Partial Application and Currying First Class Functions (function pointers / Functional Objects / Strategy Pattern) Lazy Evaluation (and Monads) Pure Functions (no side effects) Expressions (vs. Statements - each line of code produces a value instead of, or in addition to causing side effects) Recursion Pattern Matching Is it a free-for-all where we can do whatever the programming language supports to the limit that language supports it? Or is there a better guideline?

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  • How to structure classes in the filesystem?

    - by da_b0uncer
    I have a few (view) classes. Table, Tree, PagingColumn, SelectionColumn, SparkLineColumn, TimeColumn. currently they're flat under app/view like this: app/view/Table app/view/Tree app/view/PagingColumn ... I thought about restructuring it, because the Trees and Tables use the columns, but there are some columns, which only work in a tree, some who work in trees and tables and in the future there are probably some who only work in tables, I don't know. My first idea was like this: app/view/Table app/view/Tree app/view/column/PagingColumn app/view/column/SelectionColumn app/view/column/SparkLineColumn app/view/column/TimeColumn But since the SelectionColumn is explicitly for trees, I have the fear that future developers could get the idea of missuse them. But how to restructure it probably? Like this: app/view/table/panel/Table app/view/tree/panel/Tree app/view/tree/column/PagingColumn app/view/tree/column/SelectionColumn app/view/column/SparkLineColumn app/view/column/TimeColumn Or like this: app/view/Table app/view/Tree app/view/column/SparkLineColumn app/view/column/TimeColumn app/view/column/tree/PagingColumn app/view/column/tree/SelectionColumn

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