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  • Windows Services don't automatically start after reboot?

    - by James Crowley
    We've got some Windows services written in .NET. They start fine manually within the services mmc, but despite being set to Automatic, they never start when powering on (or rebooting) the machine. Update In the event log, instead of seeing "xyz started", alongside all the other services starting, I just see "The xyz service entered the stopped state." and a seperate error that says "A timeout (30000 milliseconds) was reached while waiting for a transaction response from the slsvc service.". If I manually start them, then I get a normal in the event log as expected, and all is fine - until the next Windows Update patch which forces a reboot and all the services are off again. Any ideas? I've tried setting them to Delayed Start with no apparent difference.

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  • DRBD with MySQL

    - by tdimmig
    Question about using DRBD to provide HA for MySQL. I need to be sure that my backup MySQL instance is always going to be in a functional state when the failover occurs. What happens, for example, if the primary dies part way through committing a transaction? Are we going to end up with data copied to the secondary that mysql can't handle? Or, what if the network goes away while the two are syncing, and not all of the data makes it across. It seems like it's possible to get into a state where incomplete data on the secondary makes it impossible for mysql to start up and read the database. Am I missing something?

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  • Puppet: hanging at Schedule[weekly]

    - by Andrei Serdeliuc
    Why would puppet hang at Schedule[weekly]? I'm running puppet in a masterless setup, so to apply by manifest I'm just running puppet apply /etc/puppet/manifests/site.pp In debug mode, these are the last things it says before it just hangs debug: /Schedule[never]: Skipping device resources because running on a host debug: /Schedule[daily]: Skipping device resources because running on a host debug: /Schedule[monthly]: Skipping device resources because running on a host debug: /Schedule[puppet]: Skipping device resources because running on a host debug: /Schedule[hourly]: Skipping device resources because running on a host debug: /Schedule[weekly]: Skipping device resources because running on a host If I send a SIGINT, it says Exiting debug: Storing state debug: Stored state in 0.03 seconds debug: Finishing transaction 69992657242500 Thanks

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  • Puppet:get real-time status of catalog evaluation and post to remote server

    - by txworking
    According to this article http://docs.puppetlabs.com/guides/puppet_internals.html There are four phases when puppet agent got a catalog from master. resource generation = relationships = evaluation = reporting Reporting As the transaction progresses, it collects logs and metrics on what it does. At the end of evaluation, it turns this information into a report, which it sends to the server (if requested). And at the end of evaluation puppet agent would generate a report and sent the report to the master. Is there a way to get real-time status of evaluation phase and post them to a remote logcollector? Glad for any suggestions.

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  • Is a "Soft Modem" (i.e. internal) really going to cause incompatibilities?

    - by Farseeker
    Thanks to the fact that our banking industry in Australia... outdated (which is the politest word I could think of when describing the banking industry)... to do a certain kind of transaction our bank requires us to use a dialup modem and send serial data to them. When reading through their documentation (last update: 1995), they state that any "Soft Modems" (by which I assume they mean internal modems, as they refer to a AMR socket on a motherboard, which I haven't seen in donkeys years) should not be used because of "possible incompatibilities" Seeing as buying an external, serial-port modem is actually quite expensive these days and I have a whole box of PCI modems taken out of a bunch of Dells I really don't want to have to buy an external modem. Additionally I think their documentation is simply outdated. Has anyone had experience with internal modems causing issues, where an external modem didn't?

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  • What would cause SQL 2008 Log Reader Agent to fail with "This process could not execute 'sp_replcmds' "?

    - by Rick
    I've seen this error message in other posts. They didn't seem to help resolving our issue. We are trying this with two SQL Server 2008 servers. I backed up my database from the source server and then restored it on our destination server. We setup basic Transaction Replication. The Snapshot Agent is working fine. The Log Reader Agent fails with the error above. Is it most likely a login issue for this job or QueryTimeout?

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  • Doing "text mode 'splash' game" during boot.

    - by Vi
    Sometimes I want to do something (for example, playing a simple text-mode game) while the system is booting up. This is especially useful when lengthy reiserfs transaction replays are happening. Current hacky way of doing it is: Put the program on initramfs. Before running /sbin/init, "openvt 2 /my/program". Turn off messages from kernel (sysrq 0) Override /dev/console with /dev/null (to prevent boot messages). The problems are: There are STILL some messages interfering with program output. I can't see boot messages by switching to that virtual terminal back. After finishing the boot sequence, /dev/tty2 ends up being attached both to getty and my program. How to do it properly without of running graphical splashes? The system is Linux Debian Squeeze, no dependency based sysv scripts.

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  • Disabling certain JBoss ports

    - by Rich
    We are trying to configure JBoss 5.1.0 to be as lightweight and as secure as possible. One of the parts of this process is to identify and close any ports we do not need. Three ports that we have outstanding but don't believe we need are: 4457 - bisocket 4712 - JBossTS Recovery Manager 4713 - JBossTS Transaction Status Manager We don't think we need any of these features (but could be wrong). Bisocket seems to be a way for JMS clients behind a firewall to communicate with JBoss. We hardly use JMS now and when we do, it is very unlikely that we will need this firewall traversing ability. I am less sure about whether we need the two JBossTS ports - I am guessing these are used in a clustered environment - we aren't clustered. So my question is, how do we disable these ports (and associated processes where possible), or if we need these ports, why do we need to keep them open?

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  • Remove MySQL ibdata1 without dumping and restoring existing proper databases

    - by Halfgaar
    My MySQL server contains two 100+ GB big databases. One was created with innodb_file_per_table and one wasn't. The one that wasn't, has been dumped, ready to be reloaded. However, the ibdata1 file is still huge and I don't have enough free space. Normal advice in this situation is to dump and remove each database, stop MySQL, then remove ibdata1 and the transaction logs, and then reload the databases. My specific question is: can I leave databases that were created with innodb_file_per_table alone? Or will they be destroyed when I remove ibdata1, even though all their files are separate? I can't afford to take this database off-line to dump and reload it. And because it's already properly made with separate files per table, it would feel pretty useless.

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  • External disk not working with Mac OS X 10.5

    - by ctx2002
    Hi: My OS is 10.5.7. I have an external hard disk, formatted as Mac OS Extended (Journaled), connected to my Mac machine through USB cable. I have used it for a while, but now it is not working. Error showed in /var/log/system.log. USBF: 2521.384 AppleUSBEHCI[0xa515800]::Found a transaction which hasn't moved in 5 seconds on bus 0xfd, timing out! (Addr: 0, EP: 0) ..... ...... kernel[0]: USBF: 2588.616 [0xa6baa00] The IOUSBFamily was not able to enumerate a device. Luckily, in my work place there is a Mac with OS 10.4, so I had plugged the disk into the 10.4 machine and it worked!!! I did checked "System Profiler" on both machines (10.5, 10.4). Under usb section, for 10.5 it shows USBEHCI, under 10.4, it shows USBOHCI. I am not a expert on USB Device , can any one tell me why 10.5 cause the problem. it was worked under 10.5

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  • What's the best practice for taking MySQL dump, encrypting it and then pushing to s3?

    - by HalogenCreative
    This current project requires that the DB be dumped, encrypted and pushed to s3. I'm wondering what might be some "best practices" for such a task. As of now I'm using a pretty straight ahead method but would like to have some better ideas where security is concerned. Here is the start of my script: mysqldump -u root --password="lepass" --all-databases --single-transaction > db.backup.sql tar -c db.backup.sql | openssl des3 -salt --passphrase foopass > db.backup.tarfile s3put backup/db.backup.tarfile db.backup.tarfile # Let's pull it down again and untar it for kicks s3get surgeryflow-backup/db/db.backup.tarfile db.backup.tarfile cat db.backup.tarfile | openssl des3 -d -salt --passphrase foopass |tar -xvj Obviously the problem is that this script everything an attacker would need to raise hell. Any thoughts, critiques and suggestions for this task will be appreciated.

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  • SQL Server 2008 (64-bit)

    - by Grace09
    I have transaction log backup failures randomly. SQL Server Log says 'Memory constraints resulted reduced backup/restore buffer sizes. Proceding with 6 buffers of size 64KB.', and the SQL Server Agent Error Log has quite a few errors like 'Unable to start Job Manager thread for job xxx', '[298] SQLServer Error: 768, Client unable to establish connection [SQLSTATE 08001]', [298] SQLServer Error: 768, SSL Provider: Not enough memory is available to complete this request [SQLSTATE 08001]'. I am really low on the memory? It has total of 32 GB, but I set maximum to 20. Task manager shows it is using 99% of physical memory. Memoryclerk-sqlbufferpool has 32GB for the Virtual Memory Reserved, and 20 GB for the Virtual Memory Committed. From the perfmon, SQLServer:Memory Manager/Total ServerMemory shows 21GB of memory in use, that's what I set the maximum to. I don't where the rest of memory go. Can anyone advice? Thanks in advance.

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  • JPA thinks I'm deleting a detached object

    - by Steve
    So, I've got a DAO that I used to load and save my domain objects using JPA. I finally managed to get the transaction stuff working (with a bunch of help from the folks here...), now I've got another issue. In my test case, I call my DAO to load a domain object with a given id, check that it got loaded and then call the same DAO to delete the object I just loaded. When I do that I get the following: java.lang.IllegalArgumentException: Removing a detached instance mil.navy.ndms.conops.common.model.impl.jpa.Group#10 at org.hibernate.ejb.event.EJB3DeleteEventListener.performDetachedEntityDeletionCheck(EJB3DeleteEventListener.java:45) at org.hibernate.event.def.DefaultDeleteEventListener.onDelete(DefaultDeleteEventListener.java:108) at org.hibernate.event.def.DefaultDeleteEventListener.onDelete(DefaultDeleteEventListener.java:74) at org.hibernate.impl.SessionImpl.fireDelete(SessionImpl.java:794) at org.hibernate.impl.SessionImpl.delete(SessionImpl.java:772) at org.hibernate.ejb.AbstractEntityManagerImpl.remove(AbstractEntityManagerImpl.java:253) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) at java.lang.reflect.Method.invoke(Method.java:600) at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:180) at $Proxy27.remove(Unknown Source) at mil.navy.ndms.conops.common.dao.impl.jpa.GroupDao.delete(GroupDao.java:499) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) at java.lang.reflect.Method.invoke(Method.java:600) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204) at $Proxy28.delete(Unknown Source) at mil.navy.ndms.conops.common.dao.impl.jpa.GroupDaoTest.testGroupDaoSave(GroupDaoTest.java:89) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) at java.lang.reflect.Method.invoke(Method.java:600) at junit.framework.TestCase.runTest(TestCase.java:164) at junit.framework.TestCase.runBare(TestCase.java:130) at junit.framework.TestResult$1.protect(TestResult.java:106) at junit.framework.TestResult.runProtected(TestResult.java:124) at junit.framework.TestResult.run(TestResult.java:109) at junit.framework.TestCase.run(TestCase.java:120) at junit.framework.TestSuite.runTest(TestSuite.java:230) at junit.framework.TestSuite.run(TestSuite.java:225) at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196) Now given that I'm using the same DAO instance, and I've not changed EntityManagers (unless Spring does so without letting me know), how can this be a detached object? My DAO code looks like this: public class GenericJPADao implements IWebDao, IDao, IDaoUtil { private static Logger logger = Logger.getLogger (GenericJPADao.class); protected Class voClass; @PersistenceContext(unitName = "CONOPS_PU") protected EntityManagerFactory emf; @PersistenceContext(unitName = "CONOPS_PU") protected EntityManager em; public GenericJPADao() { super ( ); ParameterizedType genericSuperclass = (ParameterizedType) getClass ( ).getGenericSuperclass ( ); this.voClass = (Class) genericSuperclass.getActualTypeArguments ( )[1]; } ... public void delete (INTFC modelObj, EntityManager em) { em.remove (modelObj); } @SuppressWarnings("unchecked") public INTFC findById (Long id) { return ((INTFC) em.find (voClass, id)); } } The test case code looks like: IGroup loadedGroup = dao.findById (group.getId ( )); assertNotNull (loadedGroup); assertEquals (group.getId ( ), loadedGroup.getId ( )); dao.delete (loadedGroup); // - This generates the above exception loadedGroup = dao.findById (group.getId ( )); assertNull(loadedGroup); Can anyone tell me what I'm doing wrong here? Thanks

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  • sending a $_SESSION array to my class and attempting to get the value fro it in a for loop .php

    - by eoin
    i have a class which in which iam using a method to get information from a session array via a for loop the 2 for loops in each method are used 1.to count total amount of items , and 2. to add up the total price but neither seem to be returning anything. im using the total amount to check it against the mc_gross posted value from an IPN and if the values are equal i plan to commit the sale to a database as it has been verified. for the method where im looking to get the total price im getting 0.00 returned to me. i think ive got the syntax wrong here somehow here is my class for purchase the two methods iam having trouble with are the gettotalcost() and gettotalitems() shown below is my class. <?php class purchase { private $itemnames; // from session array private $amountofitems; // from session array private $itemcost; //session array private $saleid; //posted transaction id value to be used in sale and sale item tables private $orderdate; //get current date time to be entered as datetime in sale table private $lastname; //posted from ipn private $firstname; //posted from ipn private $emailadd; //uses sessionarray value public function __construct($saleid,$firstname,$lastname) { $this->itemnames = $_SESSION['itemnames']; $this->amountofitems =$_SESSION['quantity']; $this->itemcost =$_SESSION['price']; $this->saleid = $saleid; $this->firstname = $firstname; $this->lastname = $lastname; $this->emailadd = $SESSION['username']; mail($myemail, "session vardump ", echo var_dump($_SESSION), "From: [email protected]" ); mail($myemail, "session vardump ",count($_SESSION['itemnames']) , "From: [email protected]" ); } public function commit() { $databaseinst = database::getinstance(); $databaseinst->connect(); $numrows = $databaseinst->querydb($query); //to be completed } public function gettotalitems() { $numitems; $i; for($i=0; $i < count($this->amountofitems);$i++) { $numitems += (int) $this->amountofitems[$i]; } return $numitems; } public function gettotalcost() { $totalcost; $i; for($i=0; $i < count($this->amountofitems);$i++) { $numitems = (int) $this->amountofitems[$i]; $costofitem =doubleval($this->itemcost [$i]); $totalcost += $numitems * $costofitem; } return $totalcost; } } ?> and here is where i create an instance of the class and attempt to use it. include("purchase.php"); $purchase = new purchase($_POST['txn_id'],$_POST['first_name'],$_POST['last_name']); $fullamount = $purchase->gettotalcost(); $fullAmount = number_format($fullAmount, 2); $grossAmount = $_POST['mc_gross']; if ($fullAmount != $grossAmount) { $message = "Possible Price Jack attempt! the amount the customer payed is : " . $grossAmount . " which is not equal to the full amount. the price of the products combined is " . $fullAmount. " the transaction number for which is " . $_POST['txn_id'] . "\n\n\n$req"; mail("XXXXXXXXXXXX", "Price Jack attempt ", $message, "From: [email protected]" ); exit(); // exit } thanks for the help in advance! ive also added these lines to my constructor. the mail returns that there is nothing in the vardump uh oh! mail($myemailaddress, "session vardump ", var_dump($_SESSION), "From: [email protected]" ); also added session_start(); at the top of the constructor and it dont work! help

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  • handling long running large transactions with perl dbi

    - by 1stdayonthejob
    I've got a large transaction comprising of getting lots of data from database A, do some manipulations with this data, then inserting the manipulated data into database B. I've only got permissions to select in database A but I can create tables and insert/update etc in database B. The manipulation and insertion part is written in perl and already in use for loading data into database B from other data sources, so all that's required is to get the necessary data from database A and using it to initialize the perl classes. How can I go about doing this so I can easily track back and pick up from where the error happened if any error occurs during the manipulation or insertion procedures (database disconnection, problems with class initialization because of invalid values, hard disk failure etc...)? Doing the transaction in one go doesn't seem like a good option because the amount data from database A means it would take at least a day or 2 for data manipulation and insertion into database B. The data from database A can be grouped into around 1000 groups using unique keys, with each key containing 1000s of rows each. One way I thought I could do is to write a script that does commits per group, meaning I've got to track which group has already been inserted into database B. The only way I can think of to track the progress of which groups have been processed or not is either in a log file or in a table in database B. A second way I thought could work is to dump all the necessary fields needed for loading the classes for manipulation and insertion into a flatfile, read the file to initialize the classes and insert into database B. This also means that I got to do some logging, but should narrow it down to the exact row in the flatfile if any error occurs. The script will look something like this: use strict; use warnings; use DBI; #connect to database A my $dbh = DBI->connect('dbi:oracle:my_db', $user, $password, { RaiseError => 1, AutoCommit => 0 }); #statement to get data based on group unique key my $sth = $dbh->prepare($my_sql); my @groups; #I have a list of this already open my $fh, '>>', 'my_logfile' or die "can't open logfile $!"; eval { foreach my $g (@groups){ #subroutine to check if group has already been processed, either from log file or from database table next if is_processed($g); $sth->execute($g); my $data = $sth->fetchall_arrayref; #manipulate $data, then use it to load perl classes for insertion into database B #. #. #. } print $fh "$g\n"; }; if ($@){ $dbh->rollback; die "something wrong...rollback"; } So if any errors do occur, I can just run this script again and it should skip the groups or rows that have been processed and continue. Both these methods is just variations on the same theme, and both require going back to where I've been tracking my progress (in table or file), skip the ones that've been commited to database B and process the remaining data. I'm sure there's a better way of doing this but am struggling to think of other solutions. Is there another way of handling large transactions between databases that require data manipulation between getting data out from one and inserting into another? The process doesn't need to be all in Perl, as long as I can reuse the perl classes for manipulating and inserting the data into the database.

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  • Sending emails in web applications

    - by Denise
    Hi everyone, I'm looking for some opinions here, I'm building a web application which has the fairly standard functionality of: Register for an account by filling out a form and submitting it. Receive an email with a confirmation code link Click the link to confirm the new account and log in When you send emails from your web application, it's often (usually) the case that there will be some change to the persistence layer. For example: A new user registers for an account on your site - the new user is created in the database and an email is sent to them with a confirmation link A user assigns a bug or issue to someone else - the issue is updated and email notifications are sent. How you send these emails can be critical to the success of your application. How you send them depends on how important it is that the intended recipient receives the email. We'll look at the following four strategies in relation to the case where the mail server is down, using example 1. TRANSACTIONAL & SYNCHRONOUS The sending of the email fails and the user is shown an error message saying that their account could not be created. The application will appear to be slow and unresponsive as the application waits for the connection timeout. The account is not created in the database because the transaction is rolled back. TRANSACTIONAL & ASYNCHRONOUS The transactional definition here refers to sending the email to a JMS queue or saving it in a database table for another background process to pick up and send. The user account is created in the database, the email is sent to a JMS queue for processing later. The transaction is successful and committed. The user is shown a message saying that their account was created and to check their email for a confirmation link. It's possible in this case that the email is never sent due to some other error, however the user is told that the email has been sent to them. There may be some delay in getting the email sent to the user if application support has to be called in to diagnose the email problem. NON-TRANSACTIONAL & SYNCHRONOUS The user is created in the database, but the application gets a timeout error when it tries to send the email with the confirmation link. The user is shown an error message saying that there was an error. The application is slow and unresponsive as it waits for the connection timeout When the mail server comes back to life and the user tries to register again, they are told their account already exists but has not been confirmed and are given the option of having the email re-sent to them. NON-TRANSACTIONAL & ASYNCHRONOUS The only difference between this and transactional & asynchronous is that if there is an error sending the email to the JMS queue or saving it in the database, the user account is still created but the email is never sent until the user attempts to register again. What I'd like to know is what have other people done here? Can you recommend any other solutions other than the 4 I've mentioned above? What's a reasonable way of approaching this problem? I don't want to over-engineer a system that's dealing with the (hopefully) rare situation where my mail server goes down! The simplest thing to do is to code it synchronously, but are there any other pitfalls to this approach? I guess I'm wondering if there's a best practice, I couldn't find much out there by googling.

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  • Dynamic model choice field in django formset using multiple select elements

    - by Aryeh Leib Taurog
    I posted this question on the django-users list, but haven't had a reply there yet. I have models that look something like this: class ProductGroup(models.Model): name = models.CharField(max_length=10, primary_key=True) def __unicode__(self): return self.name class ProductRun(models.Model): date = models.DateField(primary_key=True) def __unicode__(self): return self.date.isoformat() class CatalogItem(models.Model): cid = models.CharField(max_length=25, primary_key=True) group = models.ForeignKey(ProductGroup) run = models.ForeignKey(ProductRun) pnumber = models.IntegerField() def __unicode__(self): return self.cid class Meta: unique_together = ('group', 'run', 'pnumber') class Transaction(models.Model): timestamp = models.DateTimeField() user = models.ForeignKey(User) item = models.ForeignKey(CatalogItem) quantity = models.IntegerField() price = models.FloatField() Let's say there are about 10 ProductGroups and 10-20 relevant ProductRuns at any given time. Each group has 20-200 distinct product numbers (pnumber), so there are at least a few thousand CatalogItems. I am working on formsets for the Transaction model. Instead of a single select menu with the several thousand CatalogItems for the ForeignKey field, I want to substitute three drop-down menus, for group, run, and pnumber, which uniquely identify the CatalogItem. I'd also like to limit the choices in the second two drop-downs to those runs and pnumbers which are available for the currently selected product group (I can update them via AJAX if the user changes the product group, but it's important that the initial page load as described without relying on AJAX). What's the best way to do this? As a point of departure, here's what I've tried/considered so far: My first approach was to exclude the item foreign key field from the form, add the substitute dropdowns by overriding the add_fields method of the formset, and then extract the data and populate the fields manually on the model instances before saving them. It's straightforward and pretty simple, but it's not very reusable and I don't think it is the right way to do this. My second approach was to create a new field which inherits both MultiValueField and ModelChoiceField, and a corresponding MultiWidget subclass. This seems like the right approach. As Malcolm Tredinnick put it in a django-users discussion, "the 'smarts' of a field lie in the Field class." The problem I'm having is when/where to fetch the lists of choices from the db. The code I have now does it in the Field's __init__, but that means I have to know which ProductGroup I'm dealing with before I can even define the Form class, since I have to instantiate the Field when I define the form. So I have a factory function which I call at the last minute from my view--after I know what CatalogItems I have and which product group they're in--to create form/formset classes and instantiate them. It works, but I wonder if there's a better way. After all, the field should be able to determine the correct choices much later on, once it knows its current value. Another problem is that my implementation limits the entire formset to transactions relating to (CatalogItems from) a single ProductGroup. A third possibility I'm entertaining is to put it all in the Widget class. Once I have the related model instance, or the cid, or whatever the widget is given, I can get the ProductGroup and construct the drop-downs. This would solve the issues with my second approach, but doesn't seem like the right approach.

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  • Core Plot causing crash on device but not simulator.

    - by Eric
    I'm using core plot to create a small plot in one of my view controllers. I have been pulling my hair out trying to track down this error. I install on the simulator and it works fine but as soon as I put it on my device I get the following error: 2010-02-04 22:15:37.394 Achieve[127:207] *** -[NSCFString drawAtPoint:withTextStyle:inContext:]: unrecognized selector sent to instance 0x108530 2010-02-04 22:15:37.411 Achieve[127:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSCFString drawAtPoint:withTextStyle:inContext:]: unrecognized selector sent to instance 0x108530' 2010-02-04 22:15:37.427 Achieve[127:207] Stack: ( 843263261, 825818644, 843267069, 842763033, 842725440, 253481, 208187, 823956912, 823956516, 823956336, 823953488, 823952500, 823985628, 842717233, 843010887, 843009055, 860901832, 843738160, 843731504, 8797, 8692 ) terminate called after throwing an instance of 'NSException' Program received signal: “SIGABRT”. Debugger Output (as requested): #0 0x33b3db2c in __kill #1 0x33b3db20 in kill #2 0x33b3db14 in raise #3 0x33b54e3a in abort #4 0x33c5c398 in __gnu_cxx::__verbose_terminate_handler #5 0x313918a0 in _objc_terminate #6 0x33c59a8c in __cxxabiv1::__terminate #7 0x33c59b04 in std::terminate #8 0x33c59c2c in __cxa_throw #9 0x3138fe5c in objc_exception_throw #10 0x32433bfc in -[NSObject doesNotRecognizeSelector:] #11 0x323b8b18 in ___forwarding___ #12 0x323af840 in __forwarding_prep_0___ #13 0x0003de28 in -[CPTextLayer renderAsVectorInContext:] at CPTextLayer.m:117 #14 0x00032d3a in -[CPLayer drawInContext:] at CPLayer.m:146 #15 0x311c95b0 in -[CALayer _display] #16 0x311c9424 in -[CALayer display] #17 0x311c9370 in CALayerDisplayIfNeeded #18 0x311c8850 in CA::Context::commit_transaction #19 0x311c8474 in CA::Transaction::commit #20 0x311d05dc in CA::Transaction::observer_callback #21 0x323ad830 in __CFRunLoopDoObservers #22 0x323f5346 in CFRunLoopRunSpecific #23 0x323f4c1e in CFRunLoopRunInMode #24 0x335051c8 in GSEventRunModal #25 0x324a6c30 in -[UIApplication _run] #26 0x324a5230 in UIApplicationMain #27 0x0000225c in main at main.m:14 Here is my viewDidLoad method: - (void)viewDidLoad { [super viewDidLoad]; self.view.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"bg.png"]]; [self loadData]; self.graph = [[CPXYGraph alloc] initWithFrame: self.plotView.frame]; CPLayerHostingView *hostingView = self.plotView; hostingView.hostedLayer = graph; graph.paddingLeft = 50; graph.paddingTop = 10; graph.paddingRight = 10; graph.paddingBottom = 10; percentFormatter = [[NSNumberFormatter alloc] init]; [percentFormatter setPercentSymbol:@"%"]; [percentFormatter setNumberStyle:NSNumberFormatterPercentStyle]; [percentFormatter setLocale: [NSLocale currentLocale]]; [percentFormatter setMultiplier:[NSNumber numberWithInt:1]]; [percentFormatter setMaximumFractionDigits:0]; CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace; plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0) length:CPDecimalFromFloat(maxX)]; plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(minY) length:CPDecimalFromFloat(maxY-minY)]; CPLineStyle *lineStyle = [[CPLineStyle lineStyle]retain]; lineStyle.lineColor = [CPColor grayColor]; lineStyle.lineWidth = 1.0f; CPTextStyle *whiteText = [CPTextStyle textStyle]; whiteText.color = [CPColor whiteColor]; CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet; // axisSet.xAxis.majorIntervalLength = [[NSDecimalNumber decimalNumberWithString:@"0"]decimalValue]; axisSet.xAxis.minorTicksPerInterval = 0; axisSet.xAxis.majorTickLineStyle = nil; axisSet.xAxis.minorTickLineStyle = nil; axisSet.xAxis.axisLineStyle = lineStyle; axisSet.xAxis.minorTickLength = 0; axisSet.xAxis.majorTickLength = 0; axisSet.xAxis.labelFormatter = nil; axisSet.xAxis.labelTextStyle = nil; axisSet.yAxis.majorIntervalLength = [[NSDecimalNumber decimalNumberWithString:intY]decimalValue]; axisSet.yAxis.minorTicksPerInterval = 5; axisSet.yAxis.majorTickLineStyle = lineStyle; axisSet.yAxis.minorTickLineStyle = lineStyle; axisSet.yAxis.axisLineStyle = lineStyle; axisSet.yAxis.minorTickLength = 2.0f; axisSet.yAxis.majorTickLength = 4.0f; axisSet.yAxis.labelFormatter = percentFormatter; axisSet.yAxis.labelTextStyle = whiteText; CPScatterPlot *xSquaredPlot = [[[CPScatterPlot alloc]initWithFrame:graph.defaultPlotSpace.graph.bounds] autorelease]; xSquaredPlot.identifier = @"Plot"; xSquaredPlot.dataLineStyle.lineWidth = 4.0f; xSquaredPlot.dataLineStyle.lineColor = [CPColor yellowColor]; xSquaredPlot.dataSource = self; [graph addPlot:xSquaredPlot]; } Any help would be appreciated!

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  • Injecting Entitymanager via XML and not annnotations.

    - by user355543
    What I am trying to do is inject through XML almost the same way that is done through A @PersistenceContext annotation. I am in need of this because of the fact I have different entity managers I need to inject into the same DAO. The databases mirror one another and I would rather have 1 base class and for instances of that base class then create multiple classes just so I can use the @PersistenceContext annotation. Here is my example. This is what I am doing now and it works. public class ItemDaoImpl { protected EntityManager entityManager; public List<Item> getItems() { Query query = entityManager.createQuery("select i from Item i"); List<Item> s = (List<Item>)query.getResultList(); return s; } public void setEntityManger(EntityManager entityManager) { this.entityManager = entityManager; } } @Repository(value = "itemDaoStore2") public class ItemDaoImplStore2 extends ItemDaoImpl { @PersistenceContext(unitName = "persistence_unit_2") public void setEntityManger(EntityManager entityManager) { this.entityManager = entityManager; } } @Repository(value = "itemDaoStore1") public class ItemDaoImplStore1 extends ItemDaoImpl { @PersistenceContext(unitName = "persistence_unit_1") public void setEntityManger(EntityManager entityManager) { this.entityManager = entityManager; } } TransactionManagers, EntityManagers are defined below... <!-- Registers Spring's standard post-processors for annotation-based configuration like @Repository --> <context:annotation-config /> <!-- For @Transactional annotations --> <tx:annotation-driven transaction-manager="transactionManager1" /> <tx:annotation-driven transaction-manager="transactionManager2" /> <!-- This makes Spring perform @PersistenceContext/@PersitenceUnit injection: --> <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/> <!-- Drives transactions using local JPA APIs --> <bean id="transactionManager1" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory1" /> </bean> <bean id="transactionManager2" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory2" /> </bean> <bean id="entityManagerFactory1" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="persistenceUnitName" value="persistence_unit_1"/> ... </bean> <bean id="entityManagerFactory2" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="persistenceUnitName" value="persistence_unit_2"/> ... </bean> What I want to do is to NOT create classes ItemDaoImplStore2 or ItemDaoImplStore1. I want to have these as instances of ItemDaoImpl via xml instead. I do not know how to inject the entitymanager properly though. I want to simulate annotating this as a 'Repository' annotation, and I also want to be able to specify what entityManager to inject by the persistence unit name. I want something similar to the below using XML instead. <!-- Somehow annotate this instance as a @Repository annotation --> <bean id="itemDaoStore1" class="ItemDaoImpl"> <!-- Does not work since it is a LocalContainerEntityManagerFactoryBean--> <!-- Also I would perfer to do it the same way PersistenceContext works and only provide the persistence unit name. I would like to be able to specify persistence_unit_1--> <property name="entityManager" ref="entityManagerFactory1"/> </bean> <!-- Somehow annotate this instance as a @Repository annotation --> <bean id="itemDaoStore2" class="ItemDaoImpl"> <!-- Does not work since it is a LocalContainerEntityManagerFactoryBean--> <!-- Also I would perfer to do it the same way PersistenceContext works and only provide the persistence unit name. I would like to be able to specify persistence_unit_2--> <property name="entityManager" ref="entityManagerFactory2"/> </bean>

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  • Is there a potential for resource leak/double free here?

    - by nhed
    The following sample (not compiled so I won't vouch for syntax) pulls two resources from resource pools (not allocated with new), then "binds" them together with MyClass for the duration of a certain transaction. The transaction, implemented here by myFunc, attempts to protect against leakage of these resources by tracking their "ownership". The local resource pointers are cleared when its obvious that instantiation of MyClass was successful. The local catch, as well as the destructor ~MyClass return the resources to their pool (double-frees are protected by teh above mentioned clearing of the local pointers). Instantiation of MyClass can fail and result in an exception at two steps (1) actual memory allocation, or (2) at the constructor body itself. I do not have a problem with #1, but in the case of #2, if the exception is thrown AFTER m_resA & m_resB were set. Causing both the ~MyClass and the cleanup code of myFunc to assume responsibility for returning these resources to their pools. Is this a reasonable concern? Options I have considered, but didn't like: Smart pointers (like boost's shared_ptr). I didn't see how to apply to a resource pool (aside for wrapping in yet another instance). Allowing double-free to occur at this level but protecting at the resource pools. Trying to use the exception type - trying to deduce that if bad_alloc was caught that MyClass did not take ownership. This will require a try-catch in the constructor to make sure that any allocation failures in ABC() ...more code here... wont be confused with failures to allocate MyClass. Is there a clean, simple solution that I have overlooked? class SomeExtResourceA; class SomeExtResourceB; class MyClass { private: // These resources come out of a resource pool not allocated with "new" for each use by MyClass SomeResourceA* m_resA; SomeResourceB* m_resB; public: MyClass(SomeResourceA* resA, SomeResourceB* resB): m_resA(resA), m_resB(resB) { ABC(); // ... more code here, could throw exceptions } ~MyClass(){ if(m_resA){ m_resA->Release(); } if(m_resB){ m_resB->Release(); } } }; void myFunc(void) { SomeResourceA* resA = NULL; SomeResourceB* resB = NULL; MyClass* pMyInst = NULL; try { resA = g_pPoolA->Allocate(); resB = g_pPoolB->Allocate(); pMyInst = new MyClass(resA,resB); resA=NULL; // ''ownership succesfully transfered to pMyInst resB=NULL; // ''ownership succesfully transfered to pMyInst // Do some work with pMyInst; ...; delete pMyInst; } catch (...) { // cleanup // need to check if resA, or resB were allocated prior // to construction of pMyInst. if(resA) resA->Release(); if(resB) resB->Release(); delete pMyInst; throw; // rethrow caught exception } }

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  • NHibernate: How is identity Id updated when saving a transient instance?

    - by bretddog
    If I use session-per-transaction and call: session.SaveOrUpdate(entity) corrected: session.SaveOrUpdateCopy(entity) ..and entity is a transient instance with identity-Id=0. Shall the above line automatically update the Id of the entity, and make the instance persistent? Or should it do so on transaction.Commit? Or do I have to somehow code that explicitly? Obviously the Id of the database row (new, since transient) is autogenerated and saved as some number, but I'm talking about the actual parameter instance here. Which is the business logic instance. EDIT Mappings: public class StoreMap : ClassMap<Store> { public StoreMap() { Id(x => x.Id).GeneratedBy.Identity(); Map(x => x.Name); HasMany(x => x.Staff) // 1:m .Cascade.All(); HasManyToMany(x => x.Products) // m:m .Cascade.All() .Table("StoreProduct"); } } public class EmployeeMap : ClassMap<Employee> { public EmployeeMap() { Id(x => x.Id).GeneratedBy.Identity(); Map(x => x.FirstName); Map(x => x.LastName); References(x => x.Store); // m:1 } } public class ProductMap : ClassMap<Product> { public ProductMap() { Id(x => x.Id).GeneratedBy.Identity(); Map(x => x.Name).Length(20); Map(x => x.Price).CustomSqlType("decimal").Precision(9).Scale(2); HasManyToMany(x => x.StoresStockedIn) .Cascade.All() .Inverse() .Table("StoreProduct"); } } EDIT2 Class definitions: public class Store { public int Id { get; private set; } public string Name { get; set; } public IList<Product> Products { get; set; } public IList<Employee> Staff { get; set; } public Store() { Products = new List<Product>(); Staff = new List<Employee>(); } // AddProduct & AddEmployee is required. "NH needs you to set both sides before // it will save correctly" public void AddProduct(Product product) { product.StoresStockedIn.Add(this); Products.Add(product); } public void AddEmployee(Employee employee) { employee.Store = this; Staff.Add(employee); } } public class Employee { public int Id { get; private set; } public string FirstName { get; set; } public string LastName { get; set; } public Store Store { get; set; } } public class Product { public int Id { get; private set; } public string Name { get; set; } public decimal Price { get; set; } public IList<Store> StoresStockedIn { get; private set; } }

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  • Problem detaching entire object graph in GAE-J with JDO

    - by tempy
    I am trying to load the full object graph for User, which contains a collection of decks, which then contains a collection of cards, as such: User: @PersistenceCapable(detachable = "true") @Inheritance(strategy = InheritanceStrategy.SUBCLASS_TABLE) @FetchGroup(name = "decks", members = { @Persistent(name = "_Decks") }) public abstract class User { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) protected Key _ID; @Persistent protected String _UniqueIdentifier; @Persistent(mappedBy = "_Owner") @Element(dependent = "true") protected Set<Deck> _Decks; protected User() { } } Each Deck has a collection of Cards, as such: @PersistenceCapable(detachable = "true") @FetchGroup(name = "cards", members = { @Persistent(name = "_Cards") }) public class Deck { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key _ID; @Persistent String _Name; @Persistent(mappedBy = "_Parent") @Element(dependent = "true") private Set<Card> _Cards = new HashSet<Card>(); @Persistent private Set<String> _Tags = new HashSet<String>(); @Persistent private User _Owner; } And finally, each card: @PersistenceCapable public class Card { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key _ID; @Persistent private Text _Question; @Persistent private Text _Answer; @Persistent private Deck _Parent; } I am trying to retrieve and then detach the entire object graph. I can see in the debugger that it loads fine, but then when I get to detaching, I can't make anything beyond the User object load. (No Decks, no Cards). At first I tried without a transaction to simply "touch" all the fields on the attached object before detaching, but that didn't help. Then I tried adding everything to the default fetch group, but that just generated warnings about GAE not supporting joins. I tried setting the fetch plan's max fetch depth to -1, but that didn't do it. Finally, I tried using FetchGroups as you can see above, and then retrieving with the following code: PersistenceManager pm = _pmf.getPersistenceManager(); pm.setDetachAllOnCommit(true); pm.getFetchPlan().setGroup("decks"); pm.getFetchPlan().setGroup("cards"); Transaction tx = pm.currentTransaction(); Query query = null; try { tx.begin(); query = pm.newQuery(GoogleAccountsUser.class); //Subclass of User query.setFilter("_UniqueIdentifier == TheUser"); query.declareParameters("String TheUser"); List<User> results = (List<User>)query.execute(ID); //ID = Supplied parameter //TODO: Test for more than one result and throw if(results.size() == 0) { tx.commit(); return null; } else { User usr = (User)results.get(0); //usr = pm.detachCopy(usr); tx.commit(); return usr; } } finally { query.closeAll(); if (tx.isActive()) { tx.rollback(); } pm.close(); } This also doesn't work, and I'm running out of ideas...

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  • SOAP and NHibernate Session in C#

    - by Anonymous Coward
    In a set of SOAP web services the user is authenticated with custom SOAP header (username/password). Each time the user call a WS the following Auth method is called to authenticate and retrieve User object from NHibernate session: [...] public Services : Base { private User user; [...] public string myWS(string username, string password) { if( Auth(username, password) ) { [...] } } } public Base : WebService { protected static ISessionFactory sesFactory; protected static ISession session; static Base { Configuration conf = new Configuration(); [...] sesFactory = conf.BuildSessionFactory(); } private bool Auth(...) { session = sesFactory.OpenSession(); MembershipUser user = null; if (UserCredentials != null && Membership.ValidateUser(username, password)) { luser = Membership.GetUser(username); } ... try { user = (User)session.Get(typeof(User), luser.ProviderUserKey.ToString()); } catch { user = null; throw new [...] } return user != null; } } When the WS work is done the session is cleaned up nicely and everything works: the WSs create, modify and change objects and Nhibernate save them in the DB. The problems come when an user (same username/password) calls the same WS at same time from different clients (machines). The state of the saved objects are inconsistent. How do I manage the session correctly to avoid this? I searched and the documentation about Session management in NHibernate is really vast. Should I Lock over user object? Should I set up a "session share" management between WS calls from same user? Should I use Transaction in some savvy way? Thanks Update1 Yes, mSession is 'session'. Update2 Even with a non-static session object the data saved in the DB are inconsistent. The pattern I use to insert/save object is the following: var return_value = [...]; try { using(ITransaction tx = session.Transaction) { tx.Begin(); MyType obj = new MyType(); user.field = user.field - obj.field; // The fields names are i.e. but this is actually what happens. session.Save(user); session.Save(obj); tx.Commit(); return_value = obj.another_field; } } catch ([...]) { // Handling exceptions... } finally { // Clean up session.Flush(); session.Close(); } return return_value; All new objects (MyType) are correctly saved but the user.field status is not as I would expect. Even obj.another_field is correct (the field is an ID with generated=on-save policy). It is like 'user.field = user.field - obj.field;' is executed more times then necessary.

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  • Errors with parameter datatype in PostgreSql query

    - by John
    Im trying to execute a query to postgresql using the following code. It's written in C/C++ and I keep getting the following error when declaring a cursor: DECLARE CURSOR failed: ERROR: could not determine data type of parameter $1 Searching on here and on google, I can't find a solution. Can anyone find where I have made and error and why this is happening? thanks! void searchdb( PGconn *conn, char* name, char* offset ) { // Will hold the number of field in table int nFields; // Start a transaction block PGresult *res = PQexec(conn, "BEGIN"); if (PQresultStatus(res) != PGRES_COMMAND_OK) { printf("BEGIN command failed: %s", PQerrorMessage(conn)); PQclear(res); exit_nicely(conn); } // Clear result PQclear(res); printf("BEGIN command - OK\n"); //set the values to use const char *values[3] = {(char*)name, (char*)RESULTS_LIMIT, (char*)offset}; //calculate the lengths of each of the values int lengths[3] = {strlen((char*)name), sizeof(RESULTS_LIMIT), sizeof(offset)}; //state which parameters are binary int binary[3] = {0, 0, 1}; res = PQexecParams(conn, "DECLARE emprec CURSOR for SELECT name, id, 'Events' as source FROM events_basic WHERE name LIKE '$1::varchar%' UNION ALL " " SELECT name, fsq_id, 'Venues' as source FROM venues_cache WHERE name LIKE '$1::varchar%' UNION ALL " " SELECT name, geo_id, 'Cities' as source FROM static_cities WHERE name LIKE '$1::varchar%' OR FIND_IN_SET('$1::varchar%', alternate_names) != 0 LIMIT $2::int4 OFFSET $3::int4", 3, //number of parameters NULL, //ignore the Oid field values, //values to substitute $1 and $2 lengths, //the lengths, in bytes, of each of the parameter values binary, //whether the values are binary or not 0); //we want the result in text format // Fetch rows from table if (PQresultStatus(res) != PGRES_COMMAND_OK) { printf("DECLARE CURSOR failed: %s", PQerrorMessage(conn)); PQclear(res); exit_nicely(conn); } // Clear result PQclear(res); res = PQexec(conn, "FETCH ALL in emprec"); if (PQresultStatus(res) != PGRES_TUPLES_OK) { printf("FETCH ALL failed"); PQclear(res); exit_nicely(conn); } // Get the field name nFields = PQnfields(res); // Prepare the header with table field name printf("\nFetch record:"); printf("\n********************************************************************\n"); for (int i = 0; i < nFields; i++) printf("%-30s", PQfname(res, i)); printf("\n********************************************************************\n"); // Next, print out the record for each row for (int i = 0; i < PQntuples(res); i++) { for (int j = 0; j < nFields; j++) printf("%-30s", PQgetvalue(res, i, j)); printf("\n"); } PQclear(res); // Close the emprec res = PQexec(conn, "CLOSE emprec"); PQclear(res); // End the transaction res = PQexec(conn, "END"); // Clear result PQclear(res); }

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  • Azure - Part 4 - Table Storage Service in Windows Azure

    - by Shaun
    In Windows Azure platform there are 3 storage we can use to save our data on the cloud. They are the Table, Blob and Queue. Before the Chinese New Year Microsoft announced that Azure SDK 1.1 had been released and it supports a new type of storage – Drive, which allows us to operate NTFS files on the cloud. I will cover it in the coming few posts but now I would like to talk a bit about the Table Storage.   Concept of Table Storage Service The most common development scenario is to retrieve, create, update and remove data from the data storage. In the normal way we communicate with database. When we attempt to move our application over to the cloud the most common requirement should be have a storage service. Windows Azure provides a in-build service that allow us to storage the structured data, which is called Windows Azure Table Storage Service. The data stored in the table service are like the collection of entities. And the entities are similar to rows or records in the tradtional database. An entity should had a partition key, a row key, a timestamp and set of properties. You can treat the partition key as a group name, the row key as a primary key and the timestamp as the identifer for solving the concurrency problem. Different with a table in a database, the table service does not enforce the schema for tables, which means you can have 2 entities in the same table with different property sets. The partition key is being used for the load balance of the Azure OS and the group entity transaction. As you know in the cloud you will never know which machine is hosting your application and your data. It could be moving based on the transaction weight and the number of the requests. If the Azure OS found that there are many requests connect to your Book entities with the partition key equals “Novel” it will move them to another idle machine to increase the performance. So when choosing the partition key for your entities you need to make sure they indecate the category or gourp information so that the Azure OS can perform the load balance as you wish.   Consuming the Table Although the table service looks like a database, you cannot access it through the way you are using now, neither ADO.NET nor ODBC. The table service exposed itself by ADO.NET Data Service protocol, which allows you can consume it through the RESTful style by Http requests. The Azure SDK provides a sets of classes for us to connect it. There are 2 classes we might need: TableServiceContext and TableServiceEntity. The TableServiceContext inherited from the DataServiceContext, which represents the runtime context of the ADO.NET data service. It provides 4 methods mainly used by us: CreateQuery: It will create a IQueryable instance from a given type of entity. AddObject: Add the specified entity into Table Service. UpdateObject: Update an existing entity in the Table Service. DeleteObject: Delete an entity from the Table Service. Beofre you operate the table service you need to provide the valid account information. It’s something like the connect string of the database but with your account name and the account key when you created the storage service on the Windows Azure Development Portal. After getting the CloudStorageAccount you can create the CloudTableClient instance which provides a set of methods for using the table service. A very useful method would be CreateTableIfNotExist. It will create the table container for you if it’s not exsited. And then you can operate the eneities to that table through the methods I mentioned above. Let me explain a bit more through an exmaple. We always like code rather than sentence.   Straightforward Accessing to the Table Here I would like to build a WCF service on the Windows Azure platform, and for now just one requirement: it would allow the client to create an account entity on the table service. The WCF service would have a method named Register and accept an instance of the account which the client wants to create. After perform some validation it will add the entity into the table service. So the first thing I should do is to create a Cloud Application on my VIstial Studio 2010 RC. (The Azure SDK 1.1 only supports VS2008 and VS2010 RC.) The solution should be like this below. Then I added a configuration items for the storage account through the Settings section under the cloud project. (Double click the Services file under Roles folder and navigate to the Setting section.) This setting will be used when to retrieve my storage account information. Since for now I just in the development phase I will select “UseDevelopmentStorage=true”. And then I navigated to the WebRole.cs file under my WCF project. If you have read my previous posts you would know that this file defines the process when the application start, and terminate on the cloud. What I need to do is to when the application start, set the configuration publisher to load my config file with the config name I specified. So the code would be like below. I removed the original service and contract created by the VS template and add my IAccountService contract and its implementation class - AccountService. And I add the service method Register with the parameters: email, password and it will return a boolean value to indicates the result which is very simple. At this moment if I press F5 the application will be established on my local development fabric and I can see my service runs well through the browser. Let’s implement the service method Rigister, add a new entity to the table service. As I said before the entities you want to store in the table service must have 3 properties: partition key, row key and timespan. You can create a class with these 3 properties. The Azure SDK provides us a base class for that named TableServiceEntity in Microsoft.WindowsAzure.StorageClient namespace. So what we need to do is more simply, create a class named Account and let it derived from the TableServiceEntity. And I need to add my own properties: Email, Password, DateCreated and DateDeleted. The DateDeleted is a nullable date time value to indecate whether this entity had been deleted and when. Do you notice that I missed something here? Yes it’s the partition key and row key I didn’t assigned. The TableServiceEntity base class defined 2 constructors one was a parameter-less constructor which will be used to fill values into the properties from the table service when retrieving data. The other was one with 2 parameters: partition key and row key. As I said below the partition key may affect the load balance and the row key must be unique so here I would like to use the email as the parition key and the email plus a Guid as the row key. OK now we finished the entity class we need to store onto the table service. The next step is to create a data access class for us to add it. Azure SDK gives us a base class for it named TableServiceContext as I mentioned below. So let’s create a class for operate the Account entities. The TableServiceContext need the storage account information for its constructor. It’s the combination of the storage service URI that we will create on Windows Azure platform, and the relevant account name and key. The TableServiceContext will use this information to find the related address and verify the account to operate the storage entities. Hence in my AccountDataContext class I need to override this constructor and pass the storage account into it. All entities will be saved in the table storage with one or many tables which we call them “table containers”. Before we operate an entity we need to make sure that the table container had been created on the storage. There’s a method we can use for that: CloudTableClient.CreateTableIfNotExist. So in the constructor I will perform it firstly to make sure all method will be invoked after the table had been created. Notice that I passed the storage account enpoint URI and the credentials to specify where my storage is located and who am I. Another advise is that, make your entity class name as the same as the table name when create the table. It will increase the performance when you operate it over the cloud especially querying. Since the Register WCF method will add a new account into the table service, here I will create a relevant method to add the account entity. Before implement, I should add a reference - System.Data.Services.Client to the project. This reference provides some common method within the ADO.NET Data Service which can be used in the Windows Azure Table Service. I will use its AddObject method to create my account entity. Since the table service are not fully implemented the ADO.NET Data Service, there are some methods in the System.Data.Services.Client that TableServiceContext doesn’t support, such as AddLinks, etc. Then I implemented the serivce method to add the account entity through the AccountDataContext. You can see in the service implmentation I load the storage account information through my configuration file and created the account table entity from the parameters. Then I created the AccountDataContext. If it’s my first time to invoke this method the constructor of the AccountDataContext will create a table container for me. Then I use Add method to add the account entity into the table. Next, let’s create a farely simple client application to test this service. I created a windows console application and added a service reference to my WCF service. The metadata information of the WCF service cannot be retrieved if it’s deployed on the Windows Azure even though the <serviceMetadata httpGetEnabled="true"/> had been set. If we need to get its metadata we can deploy it on the local development service and then changed the endpoint to the address which is on the cloud. In the client side app.config file I specified the endpoint to the local development fabric address. And the just implement the client to let me input an email and a password then invoke the WCF service to add my acocunt. Let’s run my application and see the result. Of course it should return TRUE to me. And in the local SQL Express I can see the data had been saved in the table.   Summary In this post I explained more about the Windows Azure Table Storage Service. I also created a small application for demostration of how to connect and consume it through the ADO.NET Data Service Managed Library provided within the Azure SDK. I only show how to create an eneity in the storage service. In the next post I would like to explain about how to query the entities with conditions thruogh LINQ. I also would like to refactor my AccountDataContext class to make it dyamic for any kinds of entities.   Hope this helps, Shaun   All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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