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  • The Best Data Integration for Exadata Comes from Oracle

    - by maria costanzo
    Oracle Data Integrator and Oracle GoldenGate offer unique and optimized data integration solutions for Oracle Exadata. For example, customers that choose to feed their data warehouse or reporting database with near real-time throughout the day, can do so without decreasing  performance or availability of source and target systems. And if you ask why real-time, the short answer is: in today’s fast-paced, always-on world, business decisions need to use more relevant, timely data to be able to act fast and seize opportunities. A longer response to "why real-time" question can be found in a related blog post. If we look at the solution architecture, as shown on the diagram below,  Oracle Data Integrator and Oracle GoldenGate are both uniquely designed to take full advantage of the power of the database and to eliminate unnecessary middle-tier components. Oracle Data Integrator (ODI) is the best bulk data loading solution for Exadata. ODI is the only ETL platform that can leverage the full power of Exadata, integrate directly on the Exadata machine without any additional hardware, and by far provides the simplest setup and fastest overall performance on an Exadata system. We regularly see customers achieving a 5-10 times boost when they move their ETL to ODI on Exadata. For  some companies the performance gain is even much higher. For example a large insurance company did a proof of concept comparing ODI vs a traditional ETL tool (one of the market leaders) on Exadata. The same process that was taking 5hrs and 11 minutes to complete using the competing ETL product took 7 minutes and 20 seconds with ODI. Oracle Data Integrator was 42 times faster than the conventional ETL when running on Exadata.This shows that Oracle's own data integration offering helps you to gain the most out of your Exadata investment with a truly optimized solution. GoldenGate is the best solution for streaming data from heterogeneous sources into Exadata in real time. Oracle GoldenGate can also be used together with Data Integrator for hybrid use cases that also demand non-invasive capture, high-speed real time replication. Oracle GoldenGate enables real-time data feeds from heterogeneous sources non-invasively, and delivers to the staging area on the target Exadata system. ODI runs directly on Exadata to use the database engine power to perform in-database transformations. Enterprise Data Quality is integrated with Oracle Data integrator and enables ODI to load trusted data into the data warehouse tables. Only Oracle can offer all these technical benefits wrapped into a single intelligence data warehouse solution that runs on Exadata. Compared to traditional ETL with add-on CDC this solution offers: §  Non-invasive data capture from heterogeneous sources and avoids any performance impact on source §  No mid-tier; set based transformations use database power §  Mini-batches throughout the day –or- bulk processing nightly which means maximum availability for the DW §  Integrated solution with Enterprise Data Quality enables leveraging trusted data in the data warehouse In addition to Starwood Hotels and Resorts, Morrison Supermarkets, United Kingdom’s fourth-largest food retailer, has seen the power of this solution for their new BI platform and shared their story with us. Morrisons needed to analyze data across a large number of manufacturing, warehousing, retail, and financial applications with the goal to achieve single view into operations for improved customer service. The retailer deployed Oracle GoldenGate and Oracle Data Integrator to bring new data into Oracle Exadata in near real-time and replicate the data into reporting structures within the data warehouse—extending visibility into operations. Using Oracle's data integration offering for Exadata, Morrisons produced financial reports in seconds, rather than minutes, and improved staff productivity and agility. You can read more about Morrison’s success story here and hear from Starwood here. From an Irem Radzik article.

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  • Ubuntu ONE (Windows BETA) locks up - What to do?

    - by Zusch
    OS: Windows XP SP3 Hardware: Dell Precision M4400 (Laptop) CPU: Core2Duo T9600 Mem: 4 GB Installer- setup, first start and account- setup of UbuntuONE Windows client passed with no problems. After restart of UbuntuONE, the CPU- usage shows 50% (100% core usage). Exit- command (from context-menu) hides the trayicon, but the program is still working excessive in background (50% cpu- / 50 MB memory- usage), until UbuntuOneClient.exe is killed by the taskmanager. What's going on ?

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  • Ubuntu One Music - 'Unable to Parse '2006-12-12T08:00:00Z' as integer (iTunes Non-DRM AAC)

    - by Scott
    Good Morning; Title says most of it, uploaded a new song to my U1 Music (via my Android using the Files app). Which is an recently purchased iTunes .m4a song, so is non-DRM AAC. Uploaded fine, and browsing in U1 Music I see artist "Spray" fine, and then the Album, but attempting to open the Album to the song, returns: "'Unable to Parse '2006-12-12T08:00:00Z' as integer" Not sure if it's a problem with the file itself, or just how Android uploaded the file, as that is clearly a weird date code. All my other music is fine, no errors, and the service works awesome. My U1 account is under the e-mail address used for this question. Thanks!

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  • Data access pattern

    - by andlju
    I need some advice on what kind of pattern(s) I should use for pushing/pulling data into my application. I'm writing a rule-engine that needs to hold quite a large amount of data in-memory in order to be efficient enough. I have some rather conflicting requirements; It is not acceptable for the engine to always have to wait for a full pre-load of all data before it is functional. Only fetching and caching data on-demand will lead to the engine taking too long before it is running quickly enough. An external event can trigger the need for specific parts of the data to be reloaded. Basically, I think I need a combination of pushing and pulling data into the application. A simplified version of my current "pattern" looks like this (in psuedo-C# written in notepad): // This interface is implemented by all classes that needs the data interface IDataSubscriber { void RegisterData(Entity data); } // This interface is implemented by the data access class interface IDataProvider { void EnsureLoaded(Key dataKey); void RegisterSubscriber(IDataSubscriber subscriber); } class MyClassThatNeedsData : IDataSubscriber { IDataProvider _provider; MyClassThatNeedsData(IDataProvider provider) { _provider = provider; _provider.RegisterSubscriber(this); } public void RegisterData(Entity data) { // Save data for later StoreDataInCache(data); } void UseData(Key key) { // Make sure that the data has been stored in cache _provider.EnsureLoaded(key); Entity data = GetDataFromCache(key); } } class MyDataProvider : IDataProvider { List<IDataSubscriber> _subscribers; // Make sure that the data for key has been loaded to all subscribers public void EnsureLoaded(Key key) { if (HasKeyBeenMarkedAsLoaded(key)) return; PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } // Force all subscribers to get a new version of the data for key public void ForceReload(Key key) { PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } void PublishDataToSubscribers(Key key) { Entity data = FetchDataFromStore(key); foreach(var subscriber in _subscribers) { subscriber.RegisterData(data); } } } // This class will be spun off on startup and should make sure that all data is // preloaded as quickly as possible class MyPreloadingThread { IDataProvider _provider; MyPreloadingThread(IDataProvider provider) { _provider = provider; } void RunInBackground() { IEnumerable<Key> allKeys = GetAllKeys(); foreach(var key in allKeys) { _provider.EnsureLoaded(key); } } } I have a feeling though that this is not necessarily the best way of doing this.. Just the fact that explaining it seems to take two pages feels like an indication.. Any ideas? Any patterns out there I should have a look at?

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  • My simple program runs on Android emulator, but not on my Nexus One

    - by noisesolo
    To clarify, I have no trouble getting the Nexus One connected in developer's mode. I can actually get Eclipse to "run" my program on my Nexus One. However, my Nexus One simply gets stuck in a reboot loop. I've also created an .apk file and put it onto my Nexus One, installing it with apkInstaller. However, it crashed while installing. I see my app on my phone, but I'm kind of afraid to run it. I am not doing anything fancy in my program; all it does is generate text by shuffling a couple arrays of strings together. It uses a bunch of text views, two buttons, and a spinner. I have only edited the main source file, the strings XML file, and the layout XML file, nothing else. It's a 2.1-update1 program and it runs fine on the emulator. Does anyone have any idea what's going on? I'm using Windows 7 (32 bit) and my Nexus One is running Cyanogen 5.0.7.1. I'm pretty sure it's my code that's causing the problem. Now I'm just wondering if there are any common mistakes that would lead my app to run on the emulator but not on my device. Thanks in advance.

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  • Data access pattern, combining push and pull?

    - by andlju
    I need some advice on what kind of pattern(s) I should use for pushing/pulling data into my application. I'm writing a rule-engine that needs to hold quite a large amount of data in-memory in order to be efficient enough. I have some rather conflicting requirements; It is not acceptable for the engine to always have to wait for a full pre-load of all data before it is functional. Only fetching and caching data on-demand will lead to the engine taking too long before it is running quickly enough. An external event can trigger the need for specific parts of the data to be reloaded. Basically, I think I need a combination of pushing and pulling data into the application. A simplified version of my current "pattern" looks like this (in psuedo-C# written in notepad): // This interface is implemented by all classes that needs the data interface IDataSubscriber { void RegisterData(Entity data); } // This interface is implemented by the data access class interface IDataProvider { void EnsureLoaded(Key dataKey); void RegisterSubscriber(IDataSubscriber subscriber); } class MyClassThatNeedsData : IDataSubscriber { IDataProvider _provider; MyClassThatNeedsData(IDataProvider provider) { _provider = provider; _provider.RegisterSubscriber(this); } public void RegisterData(Entity data) { // Save data for later StoreDataInCache(data); } void UseData(Key key) { // Make sure that the data has been stored in cache _provider.EnsureLoaded(key); Entity data = GetDataFromCache(key); } } class MyDataProvider : IDataProvider { List<IDataSubscriber> _subscribers; // Make sure that the data for key has been loaded to all subscribers public void EnsureLoaded(Key key) { if (HasKeyBeenMarkedAsLoaded(key)) return; PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } // Force all subscribers to get a new version of the data for key public void ForceReload(Key key) { PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } void PublishDataToSubscribers(Key key) { Entity data = FetchDataFromStore(key); foreach(var subscriber in _subscribers) { subscriber.RegisterData(data); } } } // This class will be spun off on startup and should make sure that all data is // preloaded as quickly as possible class MyPreloadingThread { IDataProvider _provider; MyPreloadingThread(IDataProvider provider) { _provider = provider; } void RunInBackground() { IEnumerable<Key> allKeys = GetAllKeys(); foreach(var key in allKeys) { _provider.EnsureLoaded(key); } } } I have a feeling though that this is not necessarily the best way of doing this.. Just the fact that explaining it seems to take two pages feels like an indication.. Any ideas? Any patterns out there I should have a look at?

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  • OneToOne JPA / Hibernate eager loading cause N+1 select

    - by Alexandre Lavoie
    I created a method to have multilingual text on different objects without creating field for each languages or tables for each objects types. Now the only problem I've got is N+1 select queries when doing a simple loading. Tables schema : CREATE TABLE `testentities` ( `keyTestEntity` int(11) NOT NULL, `keyMultilingualText` int(11) NOT NULL, PRIMARY KEY (`keyTestEntity`) ) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8; CREATE TABLE `common_multilingualtexts` ( `keyMultilingualText` int(11) NOT NULL auto_increment, PRIMARY KEY (`keyMultilingualText`) ) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8; CREATE TABLE `common_multilingualtexts_values` ( `languageCode` varchar(5) NOT NULL, `keyMultilingualText` int(11) NOT NULL, `value` text, PRIMARY KEY (`languageCode`,`keyMultilingualText`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; MultilingualText.java @Entity @Table(name = "common_multilingualtexts") public class MultilingualText implements Serializable { private Integer m_iKeyMultilingualText; private Map<String, String> m_lValues = new HashMap<String, String>(); public void setKeyMultilingualText(Integer p_iKeyMultilingualText) { m_iKeyMultilingualText = p_iKeyMultilingualText; } @Id @GeneratedValue @Column(name = "keyMultilingualText") public Integer getKeyMultilingualText() { return m_iKeyMultilingualText; } public void setValues(Map<String, String> p_lValues) { m_lValues = p_lValues; } @ElementCollection(fetch = FetchType.EAGER) @CollectionTable(name = "common_multilingualtexts_values", joinColumns = @JoinColumn(name = "keyMultilingualText")) @MapKeyColumn(name = "languageCode") @Column(name = "value") public Map<String, String> getValues() { return m_lValues; } public void put(String p_sLanguageCode, String p_sValue) { m_lValues.put(p_sLanguageCode,p_sValue); } public String get(String p_sLanguageCode) { if(m_lValues.containsKey(p_sLanguageCode)) { return m_lValues.get(p_sLanguageCode); } return null; } } And it is used like this on a object (having a foreign key to the multilingual text) : @Entity @Table(name = "testentities") public class TestEntity implements Serializable { private Integer m_iKeyEntity; private MultilingualText m_oText; public void setKeyEntity(Integer p_iKeyEntity) { m_iKeyEntity = p_iKeyEntity; } @Id @GeneratedValue @Column(name = "keyEntity") public Integer getKeyEntity() { return m_iKeyEntity; } public void setText(MultilingualText p_oText) { m_oText = p_oText; } @OneToOne(cascade = CascadeType.ALL) @JoinColumn(name = "keyText") public MultilingualText getText() { return m_oText; } } Now, when doing a simple HQL query : from TestEntity, I get a query selecting TestEntity's and one query for each MultilingualText that need to be loaded on each TestEntity. I've searched a lot and found absolutely no solutions. I have tested : @Fetch(FetchType.JOIN) optional = false @ManyToOne instead of @OneToOne Now I am out of idea!

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  • Import csv data (SDK iphone)

    - by Ni
    I am new to cocoa. I have been working on these stuff for a few days. For the following code, i can read all the data in the string, and successfully get the data for plot. NSMutableArray *contentArray = [NSMutableArray array]; NSString *filePath = @"995,995,995,995,995,995,995,995,1000,997,995,994,992,993,992,989,988,987,990,993,989"; NSArray *myText = [filePath componentsSeparatedByString:@","]; NSInteger idx; for (idx = 0; idx < myText.count; idx++) { NSString *data =[myText objectAtIndex:idx]; NSLog(@"%@", data); id x = [NSNumber numberWithFloat:0+idx*0.002777778]; id y = [NSDecimalNumber decimalNumberWithString:data]; [contentArray addObject: [NSMutableDictionary dictionaryWithObjectsAndKeys:x, @"x", y, @"y", nil]]; } self.dataForPlot = contentArray; then, i try to load the data from csv file. the data in Data.csv file has the same value and the same format as 995,995,995,995,995,995,995,995,1000,997,995,994,992,993,992,989,988,987,990,993,989. I run the code, it is supposed to give the same graph output. however, it seems that the data is not loaded from csv file successfully. i can not figure out what's wrong with my code. NSMutableArray *contentArray = [NSMutableArray array]; NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Data" ofType:@"csv"]; NSString *Data = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil ]; if (Data) { NSArray *myText = [Data componentsSeparatedByString:@","]; NSInteger idx; for (idx = 0; idx < myText.count; idx++) { NSString *data =[myText objectAtIndex:idx]; NSLog(@"%@", data); id x = [NSNumber numberWithFloat:0+idx*0.002777778]; id y = [NSDecimalNumber decimalNumberWithString:data]; [contentArray addObject: [NSMutableDictionary dictionaryWithObjectsAndKeys:x, @"x", y, @"y",nil]]; } self.dataForPlot = contentArray; } The only difference is NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Data" ofType:@"csv"]; NSString *Data = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil ]; if (data){ } did i do anything wrong here?? Thanks for your help!!!!

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  • POST data not being received

    - by Alexander
    I've got an iPhone App that is supposed to send POST data to my server to register the device in a MySQL database so we can send notifications etc... to it. It sends it's unique identifier, device name, token, and a few other small things like passwords and usernames as a POST request to our server. The problem is that sometimes the server doesn't receive the data. And by this I mean, its not just receiving blank values for the POST inputs but, its not receiving ANY post data at all. I am logging all POST inputs to my server into some log files and when the script that relies on the POST data from the device fails (detects no data) I notice that its because NO POST data was sent. Is this a problem on the server, like refusing data or something or does this have to be on the client's side? What could be causing this?

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  • Oracle Big Data Learning Library - Click on LEARN BY PRODUCT to Open Page

    - by chberger
    Oracle Big Data Learning Library... Learn about Oracle Big Data, Data Science, Learning Analytics, Oracle NoSQL Database, and more! Oracle Big Data Essentials Attend this Oracle University Course! Using Oracle NoSQL Database Attend this Oracle University class! Oracle and Big Data on OTN See the latest resource on OTN. Search Welcome Get Started Learn by Role Learn by Product Latest Additions Additional Resources Oracle Big Data Appliance Oracle Big Data and Data Science Basics Meeting the Challenge of Big Data Oracle Big Data Tutorial Video Series Oracle MoviePlex - a Big Data End-to-End Series of Demonstrations Oracle Big Data Overview Oracle Big Data Essentials Data Mining Oracle NoSQL Database Tutorial Videos Oracle NoSQL Database Tutorial Series Oracle NoSQL Database Release 2 New Features Using Oracle NoSQL Database Exalytics Enterprise Manager 12c R3: Manage Exalytics Setting Up and Running Summary Advisor on an E s Oracle R Enterprise Oracle R Enterprise Tutorial Series Oracle Big Data Connectors Integrate All Your Data with Oracle Big Data Connectors Using Oracle Direct Connector for HDFS to Read the Data from HDSF Using Oracle R Connector for Hadoop to Analyze Data Oracle NoSQL Database Oracle NoSQL Database Tutorial Videos Oracle NoSQL Database Tutorial Series Oracle NoSQL Database Release 2 New Features  Using Oracle NoSQL Database eries Oracle Business Intelligence Enterprise Edition Oracle Business Intelligence Oracle BI 11g R1: Create Analyses and Dashboards - 4 day class Oracle BI Publisher 11g R1: Fundamentals - 3 day class Oracle BI 11g R1: Build Repositories - 5 day class

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  • Let's introduce the Oracle Enterprise Data Quality family!

    - by Sarah Zanchetti
    The Oracle Enterprise Data Quality family of products helps you to achieve maximum value from their business applications by delivering fit-­for-­purpose data. OEDQ is a state-of-the-art collaborative data quality profiling, analysis, parsing, standardization, matching and merging product, designed to help you understand, improve, protect and govern the quality of the information your business uses, all from a single integrated environment. Oracle Enterprise Data Quality products are: Oracle Enterprise Data Quality Profile and Audit Oracle Enterprise Data Quality Parsing and Standardization Oracle Enterprise Data Quality Match and Merge Oracle Enterprise Data Quality Address Verification Server Oracle Enterprise Data Quality Product Data Parsing and Standardization Oracle Enterprise Data Quality Product Data Match and Merge Also, the following are some of the key features of OEDQ: Integrated data profiling, auditing, cleansing and matching Browser-based client access Ability to handle all types of data – for example customer, product, asset, financial, operational Connection to any JDBC-compliant data sources and targets Multi-user project support (role-based access, issue tracking, process annotation, and version control) Services Oriented Architecture (SOA) - support for designing processes that may be exposed to external applications as a service Designed to process large data volumes A single repository to hold data along with gathered statistics and project tracking information, with shared access Intuitive graphical user interface designed to help you solve real-world information quality issues quickly Easy, data-led creation and extension of validation and transformation rules Fully extensible architecture allowing the insertion of any required custom processing  If you need to learn more about EDQ, or get assistance for any kind of issue, the Oracle Technology Network offers a huge range of resources on Oracle software. Discuss technical problems and solutions on the Discussion Forums. Get hands-on step-by-step tutorials with Oracle By Example. Download Sample Code. Get the latest news and information on any Oracle product. You can also get further help and information with Oracle software from: My Oracle Support Oracle Support Services An Information Center is available, where you can find technical information and fast solutions to the most common already solved issues: Information Center: Oracle Enterprise Data Quality [ID 1555073.2]

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  • bidirectional OneToOne Mapping : From Entity to subclass and from superclass to Entity?

    - by Teocali
    I'm trying to establish a tricky bidirectional OneToOne mapping in hibernate. I got the following classes : @Entity @Inheritance(strategy = InheritanceType.JOINED) public class Parent { @OneToOne private AnotherEntity anotherEntity; } @Entity public class Child1 extends Parent{} @Entity public class Child2 extends Parent{} @Entity public class AnotherEntity { @OneToOne(mappedBy = "anotherEntity") private Child1 child1; @OneToOne(mappedBy = "anotherEntity") private Child1 child2; } The problem here is when I'm launching the application : I got the following message : org.hibernate.MappingException: property [anotherEntity] not found on entity [Child1] at org.hibernate.mapping.PersistentClass.getRecursiveProperty(PersistentClass.java:429) at org.hibernate.mapping.PersistentClass.getReferencedProperty(PersistentClass.java:369) at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1614) at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1362) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1727) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778) at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:189) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:350) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:335) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:567) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464) at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:631) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:588) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:645) at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:508) at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:449) at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:133) at javax.servlet.GenericServlet.init(GenericServlet.java:160) at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1266) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1185) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1080) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5015) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5302) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615) at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:962) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:536) at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1471) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:301) at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:836) at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:761) at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1436) at org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:673) at org.apache.catalina.manager.ManagerServlet.doPut(ManagerServlet.java:431) at javax.servlet.http.HttpServlet.service(HttpServlet.java:644) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:581) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) One obvious solution would be to move the anotherEntity field to Child1 and Child2, but it would mean lose the link from Parent to AnotherEntity. Any help welcome.

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  • One host on a network can't connect to one other host

    - by Max Williams
    I'm on a local network with a few other people. On of the hosts is a virtual machine running in virtualbox on a mac, which has the ip address 192.168.0.35 (the VM that is, not the mac host). Everyone except one guy can connect (ie ping, ssh etc) to that machine. When that one guy tries to ping it he gets Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 Request timeout for icmp_seq 2 which i understand is just how certain mac os's report an unreachable connection. He can ping all the other hosts on the network, ie our computers, and we can all ping the VM fine and connect to it with no problems etc. His ip is 192.168.0.17. I ssh'd onto his machine (as a new user 'anon') and saw the same problems. I can ssh onto the 192.168.0.35 VM as well. From there, i can ping other users, but when i ping the problem guy, it's unreachable that way round as well. He restarted his mac, and was fine for a while. Then, just stopped working again. He's got a different IP to before. Any ideas, anyone? Don't know enough about this stuff to even diagnose the problem. thanks, max

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  • Running two different websites domains one one IP address

    - by Akshar Prabhu Desai
    Here is my apache configuration file. I have two domain names running on same ip but i want them to point to different webapps. But in this case both point to the one intended for e-yantra.org. If I copy paste akshar.co.in part before E-yantra.org both start pointing to akshar.co.in I have two A DNS entries (one per domain name) pointing to the same IP. NameVirtualHost *:80 <VirtualHost *:80> ServerName www.e-yantra.org ServerAdmin [email protected] DocumentRoot /var/www <Directory /> Options FollowSymLinks AllowOverride All </Directory> <Directory /var/www/> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> <Directory /var/www/ci/> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> <Directory /var/www/db2/> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog /var/log/apache2/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog /var/log/apache2/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> </VirtualHost> <VirtualHost *:80> ServerName www.akshar.co.in ServerAdmin [email protected] DocumentRoot /var/akshar.co.in <Directory /var/akshar.co.in/> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> </VirtualHost>

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  • Linux software raid fails to include one device for one RAID1 array

    - by user1389890
    One of my four Linux software raid arrays drops one of its two devices when I reboot my system. The other three arrays work fine. I am running RAID1 on kernel version 2.6.32-5-amd64. Every time I reboot, /dev/md2 comes up with only one device. I can manually add the device by saying $ sudo mdadm /dev/md2 --add /dev/sdc1. This works fine, and mdadm confirms that the device has been re-added as follows: mdadm: re-added /dev/sdc1 After adding the device and and allowing the array time to resynch, this is what the output of $ cat /proc/mdstat looks like: Personalities : [raid1] md3 : active raid1 sda4[0] sdb4[1] 244186840 blocks super 1.2 [2/2] [UU] md2 : active raid1 sdc1[0] sdd1[1] 732574464 blocks [2/2] [UU] md1 : active raid1 sda3[0] sdb3[1] 722804416 blocks [2/2] [UU] md0 : active raid1 sda1[0] sdb1[1] 6835520 blocks [2/2] [UU] unused devices: <none> Then after I reboot, this is what the output of $ cat /proc/mdstat looks like: Personalities : [raid1] md3 : active raid1 sda4[0] sdb4[1] 244186840 blocks super 1.2 [2/2] [UU] md2 : active raid1 sdd1[1] 732574464 blocks [2/1] [_U] md1 : active raid1 sda3[0] sdb3[1] 722804416 blocks [2/2] [UU] md0 : active raid1 sda1[0] sdb1[1] 6835520 blocks [2/2] [UU] unused devices: <none> During reboot, here is the output of $ sudo cat /var/log/syslog | grep mdadm : Jun 22 19:00:08 rook mdadm[1709]: RebuildFinished event detected on md device /dev/md2 Jun 22 19:00:08 rook mdadm[1709]: SpareActive event detected on md device /dev/md2, component device /dev/sdc1 Jun 22 19:00:20 rook kernel: [ 7819.446412] mdadm: sending ioctl 1261 to a partition! Jun 22 19:00:20 rook kernel: [ 7819.446415] mdadm: sending ioctl 1261 to a partition! Jun 22 19:00:20 rook kernel: [ 7819.446782] mdadm: sending ioctl 1261 to a partition! Jun 22 19:00:20 rook kernel: [ 7819.446785] mdadm: sending ioctl 1261 to a partition! Jun 22 19:00:20 rook kernel: [ 7819.515844] mdadm: sending ioctl 1261 to a partition! Jun 22 19:00:20 rook kernel: [ 7819.515847] mdadm: sending ioctl 1261 to a partition! Jun 22 19:00:20 rook kernel: [ 7819.606829] mdadm: sending ioctl 1261 to a partition! Jun 22 19:00:20 rook kernel: [ 7819.606832] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:48 rook kernel: [ 8027.855616] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:48 rook kernel: [ 8027.855620] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:48 rook kernel: [ 8027.855950] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:48 rook kernel: [ 8027.855952] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:49 rook kernel: [ 8027.962169] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:49 rook kernel: [ 8027.962171] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:49 rook kernel: [ 8028.054365] mdadm: sending ioctl 1261 to a partition! Jun 22 19:03:49 rook kernel: [ 8028.054368] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.588662] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.588664] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.601990] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.601991] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.602693] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.602695] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.605981] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.605983] mdadm: sending ioctl 1261 to a partition! Jun 22 19:10:23 rook kernel: [ 9.606138] mdadm: sending ioctl 800c0910 to a partition! Jun 22 19:10:23 rook kernel: [ 9.606139] mdadm: sending ioctl 800c0910 to a partition! Jun 22 19:10:48 rook mdadm[1737]: DegradedArray event detected on md device /dev/md2 Here is the mdadm.conf file: ARRAY /dev/md0 metadata=0.90 UUID=92121d42:37f46b82:926983e9:7d8aad9b ARRAY /dev/md1 metadata=0.90 UUID=9c1bafc3:1762d51d:c1ae3c29:66348110 ARRAY /dev/md2 metadata=0.90 UUID=98cea6ca:25b5f305:49e8ec88:e84bc7f0 ARRAY /dev/md3 metadata=1.2 name=rook:3 UUID=ca3fce37:95d49a09:badd0ddc:b63a4792 I also ran $ sudo smartctl -t long /dev/sdc and no hardware issues were detected. As long as I do not reboot, /dev/md2 seems to work fine. Does anyone have any suggestions? Here is the output of $ sudo mdadm -E /dev/sdc1 after re-adding the device and letting it resync: /dev/sdc1: Magic : a92b4efc Version : 0.90.00 UUID : 98cea6ca:25b5f305:49e8ec88:e84bc7f0 (local to host rook) Creation Time : Sun Jul 13 08:05:55 2008 Raid Level : raid1 Used Dev Size : 732574464 (698.64 GiB 750.16 GB) Array Size : 732574464 (698.64 GiB 750.16 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Update Time : Mon Jun 24 07:42:49 2013 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Checksum : 5fd6cc13 - correct Events : 180998 Number Major Minor RaidDevice State this 0 8 33 0 active sync /dev/sdc1 0 0 8 33 0 active sync /dev/sdc1 1 1 8 49 1 active sync /dev/sdd1 Here is the output of $ sudo mdadm -D /dev/md2 after re-adding the device and letting it resync: /dev/md2: Version : 0.90 Creation Time : Sun Jul 13 08:05:55 2008 Raid Level : raid1 Array Size : 732574464 (698.64 GiB 750.16 GB) Used Dev Size : 732574464 (698.64 GiB 750.16 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Persistence : Superblock is persistent Update Time : Mon Jun 24 07:42:49 2013 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : 98cea6ca:25b5f305:49e8ec88:e84bc7f0 (local to host rook) Events : 0.180998 Number Major Minor RaidDevice State 0 8 33 0 active sync /dev/sdc1 1 8 49 1 active sync /dev/sdd1

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  • Oracle Enterprise Data Quality - Geared Up and Ready for OpenWorld 2012

    - by Mala Narasimharajan
    10 days and counting till Oracle OpenWorld 2012 is upon us.  Enterprise data quality is key to every information integration and consolidation initiative. At this year's OpenWorld, hear how Oracle Enterprise Data Quality provides the critical piece to achieving trusted, reliable master data and increases the value of data integration initiatives. Here are the different ways you can learn and experience Enterprise Data Quality at OpenWorld:  Conference sessions: Oracle Enterprise Data Quality: Product Overview and Roadmap - Monday 10/1/12, 1:45-2:45 PM - Moscone West - 3006 Data Preparation and Ongoing Governance with the Oracle Enterprise Data Quality Platform - Wednesday 10/3/2012, 1:15-2:15 PM - Moscone West - 3000  Data Acquisition, Migration and Integration with the Oracle Enterprise Data Quality Platform - Thursday 10/4/2012, 12:45-1:45 PM - Moscone West - 3005  Hands on Labs: Introduction to Oracle Enterprise Data Quality Platform -  Monday 10/2/2012, 4:45-5:45 PM - Marriot Marquis - Salon 1/2 Demos:  Trusted Data with Oracle Enterprise Data Quality - Moscone South, Right - S-243 (note: proceed to Middleware Demo grounds) For a list of Master Data Management and Data Quality sessions and other events click here. 

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  • SL3/SL4 - Ado.Net Data Services Error during new DataServiceCollection<T>(queryResponse)

    - by Soulhuntre
    Hey all, I have two functions in a SL project (VS2010) that do almost exactly the same thing, yet one throws an error and the other does not. It seems to be related to the projections, but I am unsure about the best way to resolve. The function that works is... public void LoadAllChunksExpandAll(DataHelperReturnHandler handler, string orderby) { DataServiceCollection<CmsChunk> data = null; DataServiceQuery<CmsChunk> theQuery = _dataservice .CmsChunks .Expand("CmsItemState") .AddQueryOption("$orderby", orderby); theQuery.BeginExecute( delegate(IAsyncResult asyncResult) { _callback_dispatcher.BeginInvoke( () => { try { DataServiceQuery<CmsChunk> query = asyncResult.AsyncState as DataServiceQuery<CmsChunk>; if (query != null) { //create a tracked DataServiceCollection from the result of the asynchronous query. QueryOperationResponse<CmsChunk> queryResponse = query.EndExecute(asyncResult) as QueryOperationResponse<CmsChunk>; data = new DataServiceCollection<CmsChunk>(queryResponse); handler(data); } } catch { handler(data); } } ); }, theQuery ); } This compiles and runs as expected. A very, very similar function (shown below) fails... public void LoadAllPagesExpandAll(DataHelperReturnHandler handler, string orderby) { DataServiceCollection<CmsPage> data = null; DataServiceQuery<CmsPage> theQuery = _dataservice .CmsPages .Expand("CmsChildPages") .Expand("CmsParentPage") .Expand("CmsItemState") .AddQueryOption("$orderby", orderby); theQuery.BeginExecute( delegate(IAsyncResult asyncResult) { _callback_dispatcher.BeginInvoke( () => { try { DataServiceQuery<CmsPage> query = asyncResult.AsyncState as DataServiceQuery<CmsPage>; if (query != null) { //create a tracked DataServiceCollection from the result of the asynchronous query. QueryOperationResponse<CmsPage> queryResponse = query.EndExecute(asyncResult) as QueryOperationResponse<CmsPage>; data = new DataServiceCollection<CmsPage>(queryResponse); handler(data); } } catch { handler(data); } } ); }, theQuery ); } Clearly the issue is the Expand projections that involve a self referencing relationship (pages can contain other pages). This is under SL4 or SL3 using ADONETDataServices SL3 Update CTP3. I am open to any work around or pointers to goo information, a Google search for the error results in two hits, neither particularly helpful that I can decipher. The short error is "An item could not be added to the collection. When items in a DataServiceCollection are tracked by the DataServiceContext, new items cannot be added before items have been loaded into the collection." The full error is... System.Reflection.TargetInvocationException was caught Message=Exception has been thrown by the target of an invocation. StackTrace: at System.RuntimeMethodHandle.InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeType typeOwner) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters) at System.Data.Services.Client.ClientType.ClientProperty.SetValue(Object instance, Object value, String propertyName, Boolean allowAdd) at System.Data.Services.Client.AtomMaterializer.ApplyItemsToCollection(AtomEntry entry, ClientProperty property, IEnumerable items, Uri nextLink, ProjectionPlan continuationPlan) at System.Data.Services.Client.AtomMaterializer.ApplyFeedToCollection(AtomEntry entry, ClientProperty property, AtomFeed feed, Boolean includeLinks) at System.Data.Services.Client.AtomMaterializer.MaterializeResolvedEntry(AtomEntry entry, Boolean includeLinks) at System.Data.Services.Client.AtomMaterializer.Materialize(AtomEntry entry, Type expectedEntryType, Boolean includeLinks) at System.Data.Services.Client.AtomMaterializer.DirectMaterializePlan(AtomMaterializer materializer, AtomEntry entry, Type expectedEntryType) at System.Data.Services.Client.AtomMaterializerInvoker.DirectMaterializePlan(Object materializer, Object entry, Type expectedEntryType) at System.Data.Services.Client.ProjectionPlan.Run(AtomMaterializer materializer, AtomEntry entry, Type expectedType) at System.Data.Services.Client.AtomMaterializer.Read() at System.Data.Services.Client.MaterializeAtom.MoveNextInternal() at System.Data.Services.Client.MaterializeAtom.MoveNext() at System.Linq.Enumerable.d_b11.MoveNext() at System.Data.Services.Client.DataServiceCollection1.InternalLoadCollection(IEnumerable1 items) at System.Data.Services.Client.DataServiceCollection1.StartTracking(DataServiceContext context, IEnumerable1 items, String entitySet, Func2 entityChanged, Func2 collectionChanged) at System.Data.Services.Client.DataServiceCollection1..ctor(DataServiceContext context, IEnumerable1 items, TrackingMode trackingMode, String entitySetName, Func2 entityChangedCallback, Func2 collectionChangedCallback) at System.Data.Services.Client.DataServiceCollection1..ctor(IEnumerable1 items) at Phinli.Dashboard.Silverlight.Helpers.DataHelper.<>c__DisplayClass44.<>c__DisplayClass46.<LoadAllPagesExpandAll>b__43() InnerException: System.InvalidOperationException Message=An item could not be added to the collection. When items in a DataServiceCollection are tracked by the DataServiceContext, new items cannot be added before items have been loaded into the collection. StackTrace: at System.Data.Services.Client.DataServiceCollection1.InsertItem(Int32 index, T item) at System.Collections.ObjectModel.Collection`1.Add(T item) InnerException: Thanks for any help!

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  • 3rd party data - Store in Data Warehouse or Primary database?

    - by brydgesk
    This is mostly a data warehouse philosophy question. My project involves an Oracle forms application, and a Teradata Data Warehouse for reporting and ad-hoc purposes. In addition to the primary data created by the users of our application, we also require data from various other sources. Currently, this 3rd party data comes via FTPd flat files directly to our Data Warehouse. To access the data, our users must use a series of custom BusinessObjects reports. My question is, would it make more sense for this data to be sent to our source Oracle system instead? Is it ever appropriate for a Data Warehouse to be the point of origin for users to access raw data? In short, is it more important that the operational database contain only the data created by your project, or that the data warehouse remain dedicated solely to reporting and analysis?

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  • jquery finish one animation then start the other one

    - by Emin
    I have one two divs and two seperate links that triggers slideDown and slideUp for the divs. When one of the divs are slided down and I click the other one, I hide the first div (slidingUp) and then open the other div (slidingDown) but, at the moment its like while one div is sliding down, the other, also in the same time, is sliding up. is there a way that would tell jquery to wait to finish sliding down of one div and only then start sliding up the other ?

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  • ASP.net MVC - OneToOne relationship with pluralized nomenclature

    - by ludicco
    Hi, I have an OneToOne relationship between my models Account and Company the table names are Accounts and Companies respectively. Here is a brief screenshot of the structure: http://cl.ly/1AEU Everything works well, but mysteriously when I use the OneToOne associations I have accessors like: var db = new DB(); var account = db.Accounts.First(); var company = account.Companies; // note the plural not the singular accessor So, what's happing is that even if using OneToOne association, I still get the plural accessor with "companies" and not "company", if it this is a pure object representation and not an EntitySet generated in case when it s an oneToMany relationship. Is there a way to get this nomenclature to be applied properly? Thanks a lot

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  • How to store some of the entity's values in another table using hibernate?

    - by nimcap
    Hi guys, is there a simple way to persist some of the fields in another class and table using hibernate. For example, I have a Person class with name, surname, email, address1, address2, city, country fields. I want my classes to be: public class Person { private String name; private String surname; private String email; private Address address; // .. } public class Address { private Person person; // to whom this belongs private String address1; private String address2; private String city; private Address country; // .. } and I want to store Address in another table. What is the best way to achieve this? Edit: I am using annotations. It does not have to be the way I described, I am looking for best practices. PS. If there is a way to make Address immutable (to use as a value object) that is even better, or maybe not because I thought everything from wrong perspective :)

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  • Starting to construct a data access layer. Things to consider?

    - by Phil
    Our organisation uses inline sql. We have been tasked with providing a suitable data access layer and are weighing up the pro's and cons of which way to go... Datasets ADO.net Linq Entity framework Subsonic Other? Some tutorials and articles I have been using for reference: http://www.asp.net/(S(pdfrohu0ajmwt445fanvj2r3))/learn/data-access/tutorial-01-vb.aspx http://www.simple-talk.com/dotnet/.net-framework/designing-a-data-access-layer-in-linq-to-sql/ http://msdn.microsoft.com/en-us/magazine/cc188750.aspx http://msdn.microsoft.com/en-us/library/aa697427(VS.80).aspx http://www.subsonicproject.com/ I'm extremely torn, and finding it very difficult to make a decision on which way to go. Our site is a series of 2 internal portals and a public web site. We are using vs2008 sp1 and framework version 3.5. Please can you give me advise on what factors to consider and any pro's and cons you have faced with your data access layer. Thanks.

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  • Using Core Data Concurrently and Reliably

    - by John Topley
    I'm building my first iOS app, which in theory should be pretty straightforward but I'm having difficulty making it sufficiently bulletproof for me to feel confident submitting it to the App Store. Briefly, the main screen has a table view, upon selecting a row it segues to another table view that displays information relevant for the selected row in a master-detail fashion. The underlying data is retrieved as JSON data from a web service once a day and then cached in a Core Data store. The data previous to that day is deleted to stop the SQLite database file from growing indefinitely. All data persistence operations are performed using Core Data, with an NSFetchedResultsController underpinning the detail table view. The problem I am seeing is that if you switch quickly between the master and detail screens several times whilst fresh data is being retrieved, parsed and saved, the app freezes or crashes completely. There seems to be some sort of race condition, maybe due to Core Data importing data in the background whilst the main thread is trying to perform a fetch, but I'm speculating. I've had trouble capturing any meaningful crash information, usually it's a SIGSEGV deep in the Core Data stack. The table below shows the actual order of events that happen when the detail table view controller is loaded: Main Thread Background Thread viewDidLoad Get JSON data (using AFNetworking) Create child NSManagedObjectContext (MOC) Parse JSON data Insert managed objects in child MOC Save child MOC Post import completion notification Receive import completion notification Save parent MOC Perform fetch and reload table view Delete old managed objects in child MOC Save child MOC Post deletion completion notification Receive deletion completion notification Save parent MOC Once the AFNetworking completion block is triggered when the JSON data has arrived, a nested NSManagedObjectContext is created and passed to an "importer" object that parses the JSON data and saves the objects to the Core Data store. The importer executes using the new performBlock method introduced in iOS 5: NSManagedObjectContext *child = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType]; [child setParentContext:self.managedObjectContext]; [child performBlock:^{ // Create importer instance, passing it the child MOC... }]; The importer object observes its own MOC's NSManagedObjectContextDidSaveNotification and then posts its own notification which is observed by the detail table view controller. When this notification is posted the table view controller performs a save on its own (parent) MOC. I use the same basic pattern with a "deleter" object for deleting the old data after the new data for the day has been imported. This occurs asynchronously after the new data has been fetched by the fetched results controller and the detail table view has been reloaded. One thing I am not doing is observing any merge notifications or locking any of the managed object contexts or the persistent store coordinator. Is this something I should be doing? I'm a bit unsure how to architect this all correctly so would appreciate any advice.

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