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  • NoSQL Java API for MySQL Cluster: Questions & Answers

    - by Mat Keep
    The MySQL Cluster engineering team recently ran a live webinar, available now on-demand demonstrating the ClusterJ and ClusterJPA NoSQL APIs for MySQL Cluster, and how these can be used in building real-time, high scale Java-based services that require continuous availability. Attendees asked a number of great questions during the webinar, and I thought it would be useful to share those here, so others are also able to learn more about the Java NoSQL APIs. First, a little bit about why we developed these APIs and why they are interesting to Java developers. ClusterJ and Cluster JPA ClusterJ is a Java interface to MySQL Cluster that provides either a static or dynamic domain object model, similar to the data model used by JDO, JPA, and Hibernate. A simple API gives users extremely high performance for common operations: insert, delete, update, and query. ClusterJPA works with ClusterJ to extend functionality, including - Persistent classes - Relationships - Joins in queries - Lazy loading - Table and index creation from object model By eliminating data transformations via SQL, users get lower data access latency and higher throughput. In addition, Java developers have a more natural programming method to directly manage their data, with a complete, feature-rich solution for Object/Relational Mapping. As a result, the development of Java applications is simplified with faster development cycles resulting in accelerated time to market for new services. MySQL Cluster offers multiple NoSQL APIs alongside Java: - Memcached for a persistent, high performance, write-scalable Key/Value store, - HTTP/REST via an Apache module - C++ via the NDB API for the lowest absolute latency. Developers can use SQL as well as NoSQL APIs for access to the same data set via multiple query patterns – from simple Primary Key lookups or inserts to complex cross-shard JOINs using Adaptive Query Localization Marrying NoSQL and SQL access to an ACID-compliant database offers developers a number of benefits. MySQL Cluster’s distributed, shared-nothing architecture with auto-sharding and real time performance makes it a great fit for workloads requiring high volume OLTP. Users also get the added flexibility of being able to run real-time analytics across the same OLTP data set for real-time business insight. OK – hopefully you now have a better idea of why ClusterJ and JPA are available. Now, for the Q&A. Q & A Q. Why would I use Connector/J vs. ClusterJ? A. Partly it's a question of whether you prefer to work with SQL (Connector/J) or objects (ClusterJ). Performance of ClusterJ will be better as there is no need to pass through the MySQL Server. A ClusterJ operation can only act on a single table (e.g. no joins) - ClusterJPA extends that capability Q. Can I mix different APIs (ie ClusterJ, Connector/J) in our application for different query types? A. Yes. You can mix and match all of the API types, SQL, JDBC, ODBC, ClusterJ, Memcached, REST, C++. They all access the exact same data in the data nodes. Update through one API and new data is instantly visible to all of the others. Q. How many TCP connections would a SessionFactory instance create for a cluster of 8 data nodes? A. SessionFactory has a connection to the mgmd (management node) but otherwise is just a vehicle to create Sessions. Without using connection pooling, a SessionFactory will have one connection open with each data node. Using optional connection pooling allows multiple connections from the SessionFactory to increase throughput. Q. Can you give details of how Cluster J optimizes sharding to enhance performance of distributed query processing? A. Each data node in a cluster runs a Transaction Coordinator (TC), which begins and ends the transaction, but also serves as a resource to operate on the result rows. While an API node (such as a ClusterJ process) can send queries to any TC/data node, there are performance gains if the TC is where most of the result data is stored. ClusterJ computes the shard (partition) key to choose the data node where the row resides as the TC. Q. What happens if we perform two primary key lookups within the same transaction? Are they sent to the data node in one transaction? A. ClusterJ will send identical PK lookups to the same data node. Q. How is distributed query processing handled by MySQL Cluster ? A. If the data is split between data nodes then all of the information will be transparently combined and passed back to the application. The session will connect to a data node - typically by hashing the primary key - which then interacts with its neighboring nodes to collect the data needed to fulfil the query. Q. Can I use Foreign Keys with MySQL Cluster A. Support for Foreign Keys is included in the MySQL Cluster 7.3 Early Access release Summary The NoSQL Java APIs are packaged with MySQL Cluster, available for download here so feel free to take them for a spin today! Key Resources MySQL Cluster on-line demo  MySQL ClusterJ and JPA On-demand webinar  MySQL ClusterJ and JPA documentation MySQL ClusterJ and JPA whitepaper and tutorial

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  • iBatis get executed sql

    - by qaxi
    Hi all. Is there any way where I can get the executed query of iBatis? I want to reuse the query for an UNION query. For example: <sqlMap namespace="userSQLMap"> <select id="getUser" resultClass="UserPackage.User"> SELECT username, password FROM table WHERE id=#value# </select> </sqlMap> And when I execute the query through int id = 1 List<User> userList = queryDAO.executeForObjectList("userSQLMap.getUser",id) I want to get SELECT username, password FROM table WHERE id=1 Is there any way I could get the query? Thanks.

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  • nHibernate Criteria API Projections

    - by Craig
    I have an entity that is like this public class Customer { public Customer() { Addresses = new List<Address>(); } public int CustomerId { get; set; } public string Name { get; set; } public IList<Address> Addresses { get; set; } } And I am trying to query it using the Criteria API like this. ICriteria query = m_CustomerRepository.Query() .CreateAlias("Address", "a", NHibernate.SqlCommand.JoinType.LeftOuterJoin); var result = query .SetProjection(Projections.Distinct( Projections.ProjectionList() .Add(Projections.Alias(Projections.Property("CustomerId"), "CustomerId")) .Add(Projections.Alias(Projections.Property("Name"), "Name")) .Add(Projections.Alias(Projections.Property("Addresses"), "Addresses")) )) .SetResultTransformer(new AliasToBeanResultTransformer(typeof(Customer))) .List<Customer>() as List<Customer>; When I run this query the Addresses property of the Customer object is null. Is there anyway to add a projection for this List property?

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  • Extreme Optimization – Numerical Algorithm Support

    - by JoshReuben
    Function Delegates Many calculations involve the repeated evaluation of one or more user-supplied functions eg Numerical integration. The EO MathLib provides delegate types for common function signatures and the FunctionFactory class can generate new delegates from existing ones. RealFunction delegate - takes one Double parameter – can encapsulate most of the static methods of the System.Math class, as well as the classes in the Extreme.Mathematics.SpecialFunctions namespace: var sin = new RealFunction(Math.Sin); var result = sin(1); BivariateRealFunction delegate - takes two Double parameters: var atan2 = new BivariateRealFunction (Math.Atan2); var result = atan2(1, 2); TrivariateRealFunction delegate – represents a function takes three Double arguments ParameterizedRealFunction delegate - represents a function taking one Integer and one Double argument that returns a real number. The Pow method implements such a function, but the arguments need order re-arrangement: static double Power(int exponent, double x) { return ElementaryFunctions.Pow(x, exponent); } ... var power = new ParameterizedRealFunction(Power); var result = power(6, 3.2); A ComplexFunction delegate - represents a function that takes an Extreme.Mathematics.DoubleComplex argument and also returns a complex number. MultivariateRealFunction delegate - represents a function that takes an Extreme.Mathematics.LinearAlgebra.Vector argument and returns a real number. MultivariateVectorFunction delegate - represents a function that takes a Vector argument and returns a Vector. FastMultivariateVectorFunction delegate - represents a function that takes an input Vector argument and an output Matrix argument – avoiding object construction  The FunctionFactory class RealFromBivariateRealFunction and RealFromParameterizedRealFunction helper methods - transform BivariateRealFunction or a ParameterizedRealFunction into a RealFunction delegate by fixing one of the arguments, and treating this as a new function of a single argument. var tenthPower = FunctionFactory.RealFromParameterizedRealFunction(power, 10); var result = tenthPower(x); Note: There is no direct way to do this programmatically in C# - in F# you have partial value functions where you supply a subset of the arguments (as a travelling closure) that the function expects. When you omit arguments, F# generates a new function that holds onto/remembers the arguments you passed in and "waits" for the other parameters to be supplied. let sumVals x y = x + y     let sumX = sumVals 10     // Note: no 2nd param supplied.     // sumX is a new function generated from partially applied sumVals.     // ie "sumX is a partial application of sumVals." let sum = sumX 20     // Invokes sumX, passing in expected int (parameter y from original)  val sumVals : int -> int -> int val sumX : (int -> int) val sum : int = 30 RealFunctionsToVectorFunction and RealFunctionsToFastVectorFunction helper methods - combines an array of delegates returning a real number or a vector into vector or matrix functions. The resulting vector function returns a vector whose components are the function values of the delegates in the array. var funcVector = FunctionFactory.RealFunctionsToVectorFunction(     new MultivariateRealFunction(myFunc1),     new MultivariateRealFunction(myFunc2));  The IterativeAlgorithm<T> abstract base class Iterative algorithms are common in numerical computing - a method is executed repeatedly until a certain condition is reached, approximating the result of a calculation with increasing accuracy until a certain threshold is reached. If the desired accuracy is achieved, the algorithm is said to converge. This base class is derived by many classes in the Extreme.Mathematics.EquationSolvers and Extreme.Mathematics.Optimization namespaces, as well as the ManagedIterativeAlgorithm class which contains a driver method that manages the iteration process.  The ConvergenceTest abstract base class This class is used to specify algorithm Termination , convergence and results - calculates an estimate for the error, and signals termination of the algorithm when the error is below a specified tolerance. Termination Criteria - specify the success condition as the difference between some quantity and its actual value is within a certain tolerance – 2 ways: absolute error - difference between the result and the actual value. relative error is the difference between the result and the actual value relative to the size of the result. Tolerance property - specify trade-off between accuracy and execution time. The lower the tolerance, the longer it will take for the algorithm to obtain a result within that tolerance. Most algorithms in the EO NumLib have a default value of MachineConstants.SqrtEpsilon - gives slightly less than 8 digits of accuracy. ConvergenceCriterion property - specify under what condition the algorithm is assumed to converge. Using the ConvergenceCriterion enum: WithinAbsoluteTolerance / WithinRelativeTolerance / WithinAnyTolerance / NumberOfIterations Active property - selectively ignore certain convergence tests Error property - returns the estimated error after a run MaxIterations / MaxEvaluations properties - Other Termination Criteria - If the algorithm cannot achieve the desired accuracy, the algorithm still has to end – according to an absolute boundary. Status property - indicates how the algorithm terminated - the AlgorithmStatus enum values:NoResult / Busy / Converged (ended normally - The desired accuracy has been achieved) / IterationLimitExceeded / EvaluationLimitExceeded / RoundOffError / BadFunction / Divergent / ConvergedToFalseSolution. After the iteration terminates, the Status should be inspected to verify that the algorithm terminated normally. Alternatively, you can set the ThrowExceptionOnFailure to true. Result property - returns the result of the algorithm. This property contains the best available estimate, even if the desired accuracy was not obtained. IterationsNeeded / EvaluationsNeeded properties - returns the number of iterations required to obtain the result, number of function evaluations.  Concrete Types of Convergence Test classes SimpleConvergenceTest class - test if a value is close to zero or very small compared to another value. VectorConvergenceTest class - test convergence of vectors. This class has two additional properties. The Norm property specifies which norm is to be used when calculating the size of the vector - the VectorConvergenceNorm enum values: EuclidianNorm / Maximum / SumOfAbsoluteValues. The ErrorMeasure property specifies how the error is to be measured – VectorConvergenceErrorMeasure enum values: Norm / Componentwise ConvergenceTestCollection class - represent a combination of tests. The Quantifier property is a ConvergenceTestQuantifier enum that specifies how the tests in the collection are to be combined: Any / All  The AlgorithmHelper Class inherits from IterativeAlgorithm<T> and exposes two methods for convergence testing. IsValueWithinTolerance<T> method - determines whether a value is close to another value to within an algorithm's requested tolerance. IsIntervalWithinTolerance<T> method - determines whether an interval is within an algorithm's requested tolerance.

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  • Visual Studio &amp; TFS 11 &ndash; List of extensions and upgrades

    - by terje
    This post is a list of the extensions I recommend for use with Visual Studio 11. It’s coming up all the time – what to install, where are the download sites, last version, etc etc, and thus I thought it better to post it here and keep it updated. The basics are Visual Studio 11 connected to a Team Foundation Server 11. Note that we now are at Beta time, and that also many live in a side-by-side environment with Visual Studio 2010.  The side-by-side is supported by VS 11. However, if you installed a component supporting VS11 before you installed VS11, then you need to reinstall it.  The VSIX installer will understand that it is to apply those only for VS11, and will not touch – nor remove – the same for VS2010. A good example here is the Power Commands. The list is more or less in priority order. The focus is to get a setup which can be used for a complete coding experience for the whole ALM process. The list of course reflects what I use for my work , so it is by no means complete, and for some of the tools there are equally useful alternatives. Many components have not yet arrived with VS11 support.  I will add them as they arrive.  The components directly associated with Visual Studio from Microsoft should be common, see the Microsoft column. If you still need the VS2010 extensions, here they are: The extensions for VS 2010.   Components ready for VS 11, both upgrades and new ones Product Notes Latest Version License Applicable to Microsoft TFS Power Tools Beta 111 Side-by-side with TFS 2010 should work, but remove the Shell Extension from the TFS 2010 power tool first. March 2012(11.0.50321.0) Free TFS integration Yes ReSharper EAP for Beta 11 (updates very often, nearly daily) 7.0.3.261 pr. 16/3/2012 Free as EAP, Licensed later Coding & Quality No Power Commands1 Just reinstall, even if you already have it for VS2010. The reinstall will then apply it to VS 11 1.0.2.3 Free Coding Yes Visualization and Modelling SDK for beta Info here and here. Another download site and info here. Also download from MSDN Subscription site. Requires VS 11 Beta SDK 11 Free now, otherwise Part of MSDN Subscription Modeling Yes Visual Studio 11 Beta SDK Published 16.2.2012     Yes Visual Studio 11 Feedback tool1 Use this to really ease the process of sending bugs back to Microsoft. 1.1 Free as prerelase Visual Studio Yes             #1 Get via Visual Studio’s Tools | Extension Manager (or The Code Gallery). (From Adam : All these are auto updated by the Extension Manager in Visual Studio) #2 Works with ultimate only Components we wait for, not yet in a VS 11 version Product Notes Latest Version License Applicable to Microsoft       Coding Yes Inmeta Build Explorer     Free TFS integration No Build Manager Community Build Manager. Info here from Jakob   Free TFS Integration No Code Contracts Coming real soon   Free Coding & Quality Yes Code Contracts Editor Extensions     Free Coding & Quality Yes Web Std Update     Free Coding (Web) Yes (MSFT) Web Essentials     Free Coding (Web) Yes (MSFT) DotPeek It says up to .Net 4.0, but some tests indicates it seems to be able to handle 4.5. 1.0.0.7999 Free Coding/Investigation No Just Decompile Also says up to .net 4.0   Free Coding/Investigation No dotTrace     Licensed Quality No NDepend   Licensed Quality No tangible T4 editor     Lite version Free (Good enough) Coding (T4 templates) No Pex Moles are now integrated and improved in VS 11 as a new library called Fakes.     Coding & Unit Testing Yes Components which are now integrated into VS 11 Product Notes Productivity Power Tools Features integrated into VS11, with a few exceptions, I don’t think you will miss those. Fakes  Was Moles in 2010. Fakes is improved and made into a product.  NuGet Manager Included in the install, but still an extension package. Info here. Product installation, upgrades and patches for VS/TFS 11   Product Notes Date Applicable to Visual Studio 11 & TFS 11 Beta This is the beta release, and you are free to download and try it out. March 2012 Visual Studio and TFS SQL Server 2008 R2 SP1 Cumulative Update 4 The TFS 11 requires the CU1 at least, but you should go up to at least CU4, since this update solves a ghost record problem that otherwise may cause your TFS database to not release records the way it should when you clean it up, see this post for more information on that issue.  Oct 2011 SQL Server 2008 R2 SP1

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  • How to send a list of object from my MainPage.xaml to another page

    - by LivingThing
    When navigating to another page how can i make my list of object available to another page. for example in my mainpage.xaml var data2 = from query in document.Descendants("weather") select new Forecast { date = (string)query.Element("date"), tempMaxC = (string)query.Element("tempMaxC"), tempMinC = (string)query.Element("tempMinC"), weatherIconUrl = (string)query.Element("weatherIconUrl"), }; forecasts = data2.ToList<Forecast>(); .... NavigationService.Navigate(new Uri("/WeatherInfoPage.xaml", UriKind.Relative)); and then in my other class, i want to make it available so that i can use it like this private void AddPageItem(List<Forecast> forecasts) { .. }

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  • Beginner SQL question: arithmetic with multiple COUNT(*) results

    - by polygenelubricants
    Continuing with the spirit of using the Stack Exchange Data Explorer to learn SQL, (see: Can we become our own “Northwind” for teaching SQL / databases?), I've decided to try to write a query to answer a simple question (on meta): What % of stackoverflow users have over 10,000 rep?. Here's what I've done: Query#1 SELECT COUNT(*) FROM Users WHERE Users.Reputation >= 10000 Result: 556 Query#2 SELECT COUNT(*) FROM USERS Result: 227691 Now, how do I put them together into one query? What is this query idiom called? What do I need to write so I can get, say, a one-row three-column result like this: 556 227691 0,00244190592

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  • iPhone Google Maps KML Search

    - by satyam
    I'm using Google maps with KML Query. But my query string is "Japanese" string "??????" I'm using http://maps.google.co.jp. When requesting data, I'm getting "0" bytes. But the same query when I put in browser, its download a KML file. My code is as follows: query = [NSString stringWithFormat:@"http://maps.google.co.jp/maps?&near=%f,%f&q=??????&output=kml&num=%d", lat,lon, num]; NSURL* url = [NSURL URLWithString:query]; NSURLRequest* request = [NSURLRequest requestWithURL:url]; NSLog(@"Quering URL = %@", url); NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] autorelease]; NSData *myData = [NSURLConnection sendSynchronousRequest:request returningResponse: &response error: nil ]; NSInteger errorcode = [response statusCode]; I'm receiving "myData" with 0 bytes. why?

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  • Linq SqlMethods.Like fails

    - by Russell Steen
    I'm following the tips here, trying to leverage the statement that the sql doesn't get created until the enumerator is tripped. However I get the following error on the code below. I'm using Linq2Entities, not linq2sql. Is there a way to do this in Linq2entities? Method 'Boolean Like(System.String, System.String)' cannot be used on the client; it is only for translation to SQL. query = db.MyTables.Where(x => astringvar.Contains(x.Field1)); if (!String.IsNullOrEmpty(typeFilter)) { if (typeFilter.Contains('*')) { typeFilter = typeFilter.Replace('*', '%'); query = query.Where(x=> SqlMethods.Like(x.Type, typeFilter)); } else { query = query.Where(x => x.Type == typeFilter); } }

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  • First Foray&ndash;About timeout

    - by SQLMonger
    It has been quite a while since I signed up for this blog site and high time that something was posted.  I have a list of topics that I will be working through and posting.  Some I am sure will have been posted by others, but I will be sticking to the technical problems and challenges that I’ve recently faced, and the solutions that worked for me.  My motto when learning something new has always been “My kingdom for an example!”, and I plan on delivering useful examples here so others can learn from my efforts, failures and successes.   A bit of background about me… My name is Clayton Groom. I am a founding partner of a consulting firm in St. Louis Missouri, Covenant Technology Partners, LLC and focus on SQL Server Data Warehouse design, Analysis Services and Enterprise Reporting solutions.  I have been working with SQL Server since the early nineties, when it still only ran on OS/2. I love solving puzzles and technical challenges.   Enough about me… On to a real problem… SSIS Connection Time outs versus Command Time outs Last week, I was working on automating the processing for a large Analysis Services cube.  I had reworked an SSIS package and script task originally posted by Vidas Matelis that automates the process of adding new and dropping old partitions to/from an Analysis Services cube.  I had the package working great, tested, and ready for deployment.  It basically performs a query against the source system to determine if there is new data in the warehouse that will require a new partition to be added to the cube, and it checks the cube to see if there are any partitions that are present that are no longer needed in a rolling 60 month window. My client uses Tivoli for running all their production jobs, and not SQL Agent, so I had to build a command line file for Tivoli to use to run the package. Everything was going great. I had tested the command file from my development workstation using an XML configuration file to pass in server-specific parameters into the package when executed using the DTExec utility. With all the pieces ready, I updated the dtsconfig file to point to the UAT environment and started working with the Tivoli developer to test the job.  On the first run, the job failed, and from what I could see in the SSIS log, it had failed because of a timeout. Other errors in the log made me think that perhaps the connection string had not been passed into the package correctly. We bumped the Connection Manager  timeout values from 20 seconds to 120 seconds and tried again. The job still failed. After changing the command line to use the /SET option instead of the /CONFIGFILE option, we tested again, and again failure. After a number more failed attempts, and getting the Teradata DBA involved to monitor and see if we were connecting and failing or just failing to connect, we determined that the job was indeed connecting to the server and then disconnecting itself after 30 seconds.  This seemed odd, as we had the timeout values for the connection manager set to 180 seconds by then.  At this point one of the DBA’s found a post on the Teradata forum that had the clues to the puzzle: There is a separate “CommandTimeout” custom property on the Data source object that may needed to be adjusted for longer running queries.  I opened up the SSIS package, opened the data flow task that generated the partition list table and right-clicked on the data source. from the context menu, I selected “Show Advanced Editor” and found the property. Sure enough, it was set to 30 seconds. The CommandTimeout property can also be edited in the SSIS Properties sheet. In order to determine how long the timeout needed to be, I ran the query from the task in the development environment and received a response in a matter of seconds.  I then tried the same query against the production database and waited several minutes for a response. This did not seem to be a reasonable response time for the query involved, and indeed it wasn’t. The Teradata DBA’s adjusted the query governor settings for the service account I was testing with, and we were able to get the response back down under a minute.  Still, I set the CommandTimeout property to a much higher value in case the job was ever started during a time of high-demand on the production server. With this change in place, the job finally completed successfully.  The lesson learned for me was two-fold: Always compare query execution times between development and production environments, and don’t assume that production will always be faster.  With higher user demands, query governors, and a whole lot more data, the execution time of even what might seem to be simple queries can vary greatly. SSIS Connection time out settings do not affect command time outs.  Connection timeouts control how long the package will wait for a response from the server before assuming the server is not available or is not responding. Command time outs control how long a task will wait for results to start being returned before deciding that the server is not responding. Both lessons seem pretty straight forward, and I felt pretty sheepish once I finally figured out what the issue was.  To be fair though, In the 5+ years that I have been working with SSIS, I could only recall one other time where I had to set the CommandTimeout property, and that memory only resurfaced while I was penning this post.

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  • TooManyRowsAffectedException with encrypted triggers

    - by Jon Masters
    I'm using nHibernate to update 2 columns in a table that has 3 encrypted triggers on it. The triggers are not owned by me and I can not make changes to them, so unfortunately I can't SET NOCOUNT ON inside of them. Is there another way to get around the TooManyRowsAffectedException that is thrown on commit? Update 1 So far only way I've gotten around the issue is to step around the .Save routine with var query = session.CreateSQLQuery("update Orders set Notes = :Notes, Status = :Status where OrderId = :Order"); query.SetString("Notes", orderHeader.Notes); query.SetString("Status", orderHeader.OrderStatus); query.SetInt32("Order", orderHeader.OrderHeaderId); query.ExecuteUpdate(); It feels dirty and is not easily to extend, but it doesn't crater.

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  • How do these user/userParam references relate to the Customer and Account lookups?

    - by plath
    In the following code example how do the user/userParam references relate to the Customer and Account lookups and what is the relationship between Customer and Account? // PersistenceManager pm = ...; Transaction tx = pm.currentTransaction(); User user = userService.currentUser(); List<Account> accounts = new ArrayList<Account>(); try { tx.begin(); Query query = pm.newQuery("select from Customer " + "where user == userParam " + "parameters User userParam"); List<Customer> customers = (List<Customer>) query.execute(user); query = pm.newQuery("select from Account " + "where parent-pk == keyParam " + "parameters Key keyParam"); for (Customer customer : customers) { accounts.addAll((List<Account>) query.execute(customer.key)); } } finally { if (tx.isActive()) { tx.rollback(); } }

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  • How do these user/userParam references relate to the Customer and Account lookups?

    - by marmalade
    In the following code example how do the user/userParam references relate to the Customer and Account lookups and what is the relationship between Customer and Account? // PersistenceManager pm = ...; Transaction tx = pm.currentTransaction(); User user = userService.currentUser(); List<Account> accounts = new ArrayList<Account>(); try { tx.begin(); Query query = pm.newQuery("select from Customer " + "where user == userParam " + "parameters User userParam"); List<Customer> customers = (List<Customer>) query.execute(user); query = pm.newQuery("select from Account " + "where parent-pk == keyParam " + "parameters Key keyParam"); for (Customer customer : customers) { accounts.addAll((List<Account>) query.execute(customer.key)); } } finally { if (tx.isActive()) { tx.rollback(); } }

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  • Spring Data MongoDB Date between two Dates

    - by sics
    i'm using Spring Data for MongoDB and got the following classes class A { List<B> b; } class B { Date startDate; Date endDate; } when i save an object of A it gets persisted like { "_id" : "DQDVDE000VFP8E39", "b" : [ { "startDate" : ISODate("2009-10-05T22:00:00Z"), "endDate" : ISODate("2009-10-29T23:00:00Z") }, { "startDate" : ISODate("2009-11-01T23:00:00Z"), "endDate" : ISODate("2009-12-30T23:00:00Z") } ] } Now i want to query the db for documents matching entries in b where a given date is between startDate and endDate. Query query = new Query(Criteria.where("a").elemMatch( Criteria.where("startDate").gte(date) .and("endDate").lte(date) ); Which results in the following mongo query: { "margins": { "$elemMatch": { "startDate" : { "$gte" : { "$date" : "2009-11-03T23:00:00.000Z"}}, "endDate" : { "$lte" : { "$date" : "2009-11-03T23:00:00.000Z"}} } } } but returns no resulting documents. Does anybody know what i'm doing wrong? I don't get it... Thank you very much in advance!!

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  • JPA getSingleResult() or null

    - by Eugene Ramirez
    Hi. I have an insertOrUpdate method which inserts an Entity when it doesn't exist or update it if it does. To enable this, I have to findByIdAndForeignKey, if it returned null insert if not then update. The problem is how do I check if it exists? So I tried getSingleResult. But it throws an exception if the public Profile findByUserNameAndPropertyName(String userName, String propertyName) { String namedQuery = Profile.class.getSimpleName() + ".findByUserNameAndPropertyName"; Query query = entityManager.createNamedQuery(namedQuery); query.setParameter("name", userName); query.setParameter("propName", propertyName); Object result = query.getSingleResult(); if(result==null)return null; return (Profile)result; } but "getSingleResult" throws an exception. Thanks

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  • MS Access 2003 - Formatting results in a list box problem.

    - by Justin
    So I have a list box that displays averages in a table like format from a crossyab query. It's just what I need the query is right, there is just one thing. I had to set the field properties in the query as format: standard..decimal:2. Which is exactly what I needed. However..the list box will not pick up on this. First I typed the crosstab sql into the list box's properties....and then I ran into this problem. So then I actually just created the query object, saved it and set that as the rowsource for the list box. Still won't work....when I open the query it is the correct format. So is there a way to further format a text box? Is there a way tell it to limit decimal places to one or two on returned values? Thanks!

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  • JQuery and WCF - GET Method passes null

    - by user70192
    Hello, I have a WCF service that accepts requests from JQuery. Currently, I can access this service. However, the parameter value is always null. Here is my WCF Service definition: [OperationContract] [WebInvoke(Method = "GET", BodyStyle = WebMessageBodyStyle.WrappedRequest, RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)] public string ExecuteQuery(string query) { // NOTE: I get here, but the query parameter is always null string results = Engine.ExecuteQuery(query); return results; } Here is my JQuery call: var searchUrl = "/services/myService.svc/ExecuteQuery"; var json = { "query": eval("\"test query\"") }; alert(json2string(json)); // Everything is correct here if (json != null) { $.ajax({ type: "GET", url: searchUrl, contentType: "application/json; charset=utf-8", data: json2string(json), dataType: "json" }); } What am I doing wrong? It seems odd that I can call the service but the parameter is always null. Thank you

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  • Python and Plone help

    - by Grenko
    Im using the plone cms and am having trouble with a python script. I get a name error "the global name 'open' is not defined". When i put the code in a seperate python script it works fine and the information is being passed to the python script becuase i can print the query. Code is below: #Import a standard function, and get the HTML request and response objects. from Products.PythonScripts.standard import html_quote request = container.REQUEST RESPONSE = request.RESPONSE # Insert data that was passed from the form query=request.query #print query f = open("blast_query.txt","w") for i in query: f.write(i) return printed I also have a second question, can i tell python to open a file in in a certain directory for example, If the script is in a certain loaction i.e. home folder, but i want the script to open a file at home/some_directory/some_directory can it be done?

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  • Querying a Single Column with LINQ

    - by Hossein Margani
    Hi Every one! I want to fetch array of values of a single column in a table, for example, I have a table named Customer(ID,Name), and want to fetch ids of all customers. my query in LINQ is: var ids = db.Customers.Select(c=>c.ID).ToList(); The answer of this query is correct, but I ran SQL Server Profiler, and saw the query which was like this: SELECT [t0].[ID], [t0].[Name] FROM [dbo].[Customer] AS [t0] I understood that LINQ selects all columns and then creates the integer array of ID fields. How can I write a LINQ query which generates this query in SQL Server: SELECT [t0].[ID] FROM [dbo].[Customer] AS [t0] Thank you.

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  • problems with unpickling a 80 megabyte file in python

    - by tipu
    I am using the pickle module to read and write large amounts of data to a file. After writing to the file a 80 megabyte pickled file, I load it in a SocketServer using class MyTCPHandler(SocketServer.BaseRequestHandler): def handle(self): print("in handle") words_file_handler = open('/home/tipu/Dropbox/dev/workspace/search/words.db', 'rb') words = pickle.load(words_file_handler) tweets = shelve.open('/home/tipu/Dropbox/dev/workspace/search/tweets.db', 'r'); results_per_page = 25 query_details = self.request.recv(1024).strip() query_details = eval(query_details) query = query_details["query"] page = int(query_details["page"]) - 1 return_ = [] booleanquery = BooleanQuery(MyTCPHandler.words) if query.find("(") > -1: result = booleanquery.processAdvancedQuery(query) else: result = booleanquery.processQuery(query) result = list(result) i = 0 for tweet_id in result and i < 25: #return_.append(MyTCPHandler.tweets[str(tweet_id)]) return_.append(tweet_id) i += 1 self.request.send(str(return_)) However the file never seems to load after the pickle.load line and it eventually halts the connection attempt. Is there anything I can do to speed this up?

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  • What does this do and why does it require a transaction?

    - by S. Palin
    What does the following code example do and why does it require a transaction? // PersistenceManager pm = ...; Transaction tx = pm.currentTransaction(); User user = userService.currentUser(); List<Account> accounts = new ArrayList<Account>(); try { tx.begin(); Query query = pm.newQuery("select from Customer " + "where user == userParam " + "parameters User userParam"); List<Customer> customers = (List<Customer>) query.execute(user); query = pm.newQuery("select from Account " + "where parent-pk == keyParam " + "parameters Key keyParam"); for (Customer customer : customers) { accounts.addAll((List<Account>) query.execute(customer.key)); } } finally { if (tx.isActive()) { tx.rollback(); } }

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  • Filter zipcodes by proximity in Django with the Spherical Law of Cosines

    - by spiffytech
    I'm trying to handle proximity search for a basic store locater in Django. Rather than haul PostGIS around with my app just so I can use GeoDjango's distance filter, I'd like to use the Spherical Law of Cosines distance formula in a model query. I'd like all of the calculations to be done in the database in one query, for efficiency. An example MySQL query from The Internet implementing the Spherical Law of Cosines like this: SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin( radians( lat ) ) ) ) AS distance FROM stores HAVING distance < 25 ORDER BY distance LIMIT 0 , 20; The query needs to reference the Zipcode ForeignKey for each store's lat/lng values. How can I make all of this work in a Django model query?

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  • Linq to NHibernate using Queryable.Where predicate

    - by Groo
    I am querying an SQLite database using LINQ to NHibernate. Person is an entity containing an Id and a Name: public class Person { public Guid Id { get; private set; } public string Name { get; private set; } } Let's say my db table contains a single person whose name is "John". This test works as expected: var query = from item in session.Linq<Person>() where (item.Name == "Mike") select item; // no such entity should exist Assert.IsFalse(query.Any()); but this one fails: var query = from item in session.Linq<Person>() select item; query.Where(item => item.Name == "Mike"); // following line actually returns the // "John" entry Assert.IsFalse(query.Any()); What am I missing?

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  • how to have defined connection within function for pdo communication with DB

    - by Scarface
    hey guys I just started trying to convert my query structure to PDO and I have come across a weird problem. When I call a pdo query connection within a function and the connection is included outside the function, the connection becomes undefined. Anyone know what I am doing wrong here? I was just playing with it, my example is below. include("includes/connection.php"); function query(){ $user='user'; $id='100'; $sql = 'SELECT * FROM users'; $stmt = $conn->prepare($sql); $result=$stmt->execute(array($user, $id)); // now iterate over the result as if we obtained // the $stmt in a call to PDO::query() while($r = $stmt->fetch(PDO::FETCH_ASSOC)) { echo "$r[username] $r[id] \n"; } } query();

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  • GAE more than 3 attributes to filter?

    - by Vik
    Hie I am using GAE jdoql and wrote query like: Query query = pm.newQuery(BloodDonor.class); query.setFilter(" state == :stateName && district == :distName &&" + " city == :cityName && bloodGroup == :blood"); @SuppressWarnings("unchecked") List<BloodDonor> donors = (List<BloodDonor>) query.execute(state.toLowerCase(), district.toLowerCase(), city.toLowerCase(), bloodGroup.toLowerCase()); This doesnt work as execute method does not support more than 3 parameters. So how to pass more than 3

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