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• Daily tech links for .net and related technologies - June 8-11, 2010

  - by SanjeevAgarwal

  Daily tech links for .net and related technologies - June 8-11, 2010 Web Development ASPNET MVC: Handling Multiple Buttons on a Form with jQuery - Donn Building a MVC2 Template, Part 14, Logging Services - Eric Simple Accordion Menu With jQuery & ASP.NET - Steve Boschi Conditional Validation in MVC -Simonince Creating a RESTful Web Service Using ASP.Net MVC Part 23 – Bug Fixes and Area Support - Shoulders of Giants Web Design The Principles Of Cross-Browser CSS Coding - Louis Lazaris Transparency...(read more)

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• Should I choose Doctrine 2 or Propel 1.5/1.6, and why?

  - by Billy ONeal

  I'd like to hear from those who have used Doctrine 2 (or later) and Propel 1.5 (or later). Most comparisons between these two object relational mappers are based on old versions -- Doctrine 1 versus Propel 1.3/1.4, and both ORMs went through significant redesigns in their recent revisions. For example, most of the criticism of Propel seems to center around the "ModelName Peer" classes, which are deprecated in 1.5 in any case. Here's what I've accumulated so far (And I've tried to make this list as balanced as possible...): Propel Pros Extremely IDE friendly, because actual code is generated, instead of relying on PHP magic methods. This means IDE features like code completion are actually helpful. Fast (In terms of database usage -- no runtime introspection is done on the database) Clean migration between schema versions (at least in the 1.6 beta) Can generate PHP 5.3 models (i.e. namespaces) Easy to chain a lot of things into a single database query with things like useXxx methods. (See the "code completion" video above) Cons Requires an extra build step, namely building the model classes. Generated code needs rebuilt whenever Propel version is changed, a setting is changed, or the schema changes. This might be unintuitive to some and custom methods applied to the model are lost. (I think?) Some useful features (i.e. version behavior, schema migrations) are in beta status. Doctrine Pros More popular Doctrine Query Language can express potentially more complicated relationships between data than easily possible with Propel's ActiveRecord strategy. Easier to add reusable behaviors when compared with Propel. DocBlock based commenting for building the schema is embedded in the actual PHP instead of a separate XML file. Uses PHP 5.3 Namespaces everywhere Cons Requires learning an entirely new programming language (Doctrine Query Language) Implemented in terms of "magic methods" in several places, making IDE autocomplete worthless. Requires database introspection and thus is slightly slower than Propel by default; caching can remove this but the caching adds considerable complexity. Fewer behaviors are included in the core codebase. Several features Propel provides out of the box (such as Nested Set) are available only through extensions. Freakin' HUGE :) This I have gleaned though only through reading the documentation available for both tools -- I've not actually built anything yet. I'd like to hear from those who have used both tools though, to share their experience on pros/cons of each library, and what their recommendation is at this point :)

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• What are some arguments AGAINST using EntityFramework?

  - by Rachel

  The application I am currently building has been using Stored procedures and hand-crafted class models to represent database objects. Some people have suggested using Entity Framework and I am considering switching to that since I am not that far into the project. My problem is, I feel the people arguing for EF are only telling me the good side of things, not the bad side :) My main concerns are: We want Client-Side validation using DataAnnotations, and it sounds like I have to create the client-side models anyways so I am not sure that EF would save that much coding time We would like to keep the classes as small as possible when going over the network, and I have read that using EF often includes extra data that is not needed We have a complex database layer which crosses multiple databases, and I am not sure EF can handle this. We have one Common database with things like Users, StatusCodes, Types, etc and multiple instances of our main databases for different instances of the application. SELECT queries can and will query across all instances of the databases, however users can only modify objects that are in the database they are currently working on. They can switch databases without reloading the application. Object modes are very complex and there are often quite a few joins involved Arguments for EF are: Concurrency. I wouldn't have to code in checks to see if the record was updated before each save Code Generation. EF can generate partial class models and POCOs for me, however I am not positive this would really save me that much time since I think we would still need to create the client-side models for validation and some custom parsing methods. Speed of development since we wouldn't need to create the CRUD stored procedures for every database object Our current architecture consists of a WPF Service which handles database calls via parameterized Stored Procedures, POCO objects that go to/from the WCF service and the WPF client, and the WPF client itself which transforms POCOs into class Models for the purpose of Validation and DataBinding.

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• Entity Framework with large systems - how to divide models?

  - by jkohlhepp

  I'm working with a SQL Server database with 1000+ tables, another few hundred views, and several thousand stored procedures. We are looking to start using Entity Framework for our newer projects, and we are working on our strategy for doing so. The thing I'm hung up on is how best to split the tables into different models (EDMX or DbContext if we go code first). I can think of a few strategies right off the bat: Split by schema We have our tables split across probably a dozen schemas. We could do one model per schema. This isn't perfect, though, because dbo still ends up being very large, with 500+ tables / views. Another problem is that certain units of work will end up having to do transactions that span multiple models, which adds to complexity, although I assume EF makes this fairly straightforward. Split by intent Instead of worrying about schemas, split the models by intent. So we'll have different models for each application, or project, or module, or screen, depending on how granular we want to get. The problem I see with this is that there are certain tables that inevitably have to be used in every case, such as User or AuditHistory. Do we add those to every model (violates DRY I think), or are those in a separate model that is used by every project? Don't split at all - one giant model This is obviously simple from a development perspective but from my research and my intuition this seems like it could perform terribly, both at design time, compile time, and possibly run time. What is the best practice for using EF against such a large database? Specifically what strategies do people use in designing models against this volume of DB objects? Are there options that I'm not thinking of that work better than what I have above? Also, is this a problem in other ORMs such as NHibernate? If so have they come up with any better solutions than EF?

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• Entity framework support for table valued functions and thus full text

  - by simonsabin

  One of my most popular posts with over 10, 000 hits is how to enable full text when using LINQ to SQL http://sqlblogcasts.com/blogs/simons/archive/2008/12/18/LINQ-to-SQL---Enabling-Fulltext-searching.aspx , core to this is the use of a table valued function. I’m therefore interested to see that Entity Framework will support table valued functions in the next release for more details have a read of the efdesign blog http://blogs.msdn.com/b/efdesign/archive/2011/01/21/table-valued-function-support...(read more)

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• Is there really Object-relational impedance mismatch?

  - by user52763

  It is always stated that it is hard to store applications objects in relational databases - the object-relational impedance mismatch - and that is why Document databases are better. However, is there really an impedance mismatch? And object has a key (albeit it may be hidden away by the runtime as a pointer to memory), a set of values, and foreign keys to other objects. Objects are as much made up of tables as it is a document. Neither really fit. I can see a use for databases to model the data into specific shapes for scenarios in the application - e.g. to speed up database lookup and avoid joins, etc., but won't it be better to keep the data as normalized as possible at the core, and transform as required?

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• Finding a way to simplify complex queries on legacy application

  - by glenatron

  I am working with an existing application built on Rails 3.1/MySql with much of the work taking place in a JavaScript interface, although the actual platforms are not tremendously relevant here, except in that they give context. The application is powerful, handles a reasonable amount of data and works well. As the number of customers using it and the complexity of the projects they create increases, however, we are starting to run into a few performance problems. As far as I can tell, the source of these problems is that the data represents a tree and it is very hard for ActiveRecord to deterministically know what data it should be retrieving. My model has many relationships like this: Project has_many Nodes has_many GlobalConditions Node has_one Parent has_many Nodes has_many WeightingFactors through NodeFactors has_many Tags through NodeTags GlobalCondition has_many Nodes ( referenced by Id, rather than replicating tree ) WeightingFactor has_many Nodes through NodeFactors Tag has_many Nodes through NodeTags The whole system has something in the region of thirty types which optionally hang off one or many nodes in the tree. My question is: What can I do to retrieve and construct this data faster? Having worked a lot with .Net, if I was in a similar situation there, I would look at building up a Stored Procedure to pull everything out of the database in one go but I would prefer to keep my logic in the application and from what I can tell it would be hard to take the queried data and build ActiveRecord objects from it without losing their integrity, which would cause more problems than it solves. It has also occurred to me that I could bunch the data up and send some of it across asynchronously, which would not improve performance but would improve the user perception of performance. However if sections of the data appeared after page load that could also be quite confusing. I am wondering whether it would be a useful strategy to make everything aware of it's parent project, so that one could pull all the records for that project and then build up the relationships later, but given the ubiquity of complex trees in day to day programming life I wouldn't be surprised if there were some better design patterns or standard approaches to this type of situation that I am not well versed in.

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• Do you test your SQL/HQL/Criteria ?

  - by 0101

  Do you test your SQL or SQL generated by your database framework? There are frameworks like DbUnit that allow you to create real in-memory database and execute real SQL. But its very hard to use(not developer-friendly so to speak), because you need to first prepare test data(and it should not be shared between tests). P.S. I don't mean mocking database or framework's database methods, but tests that make you 99% sure that your SQL is working even after some hardcore refactoring.

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• Do ORMs enable the creation of rich domain models?

  - by Augusto

  After using Hibernate on most of my projects for about 8 years, I've landed on a company that discourages its use and wants applications to only interact with the DB through stored procedures. After doing this for a couple of weeks, I haven't been able to create a rich domain model of the application I'm starting to build, and the application just looks like a (horrible) transactional script. Some of the issues I've found are: Cannot navigate object graph as the stored procedures just load the minimum amount of data, which means that sometimes we have similar objects with different fields. One example is: we have a stored procedure to retrieve all the data from a customer, and another to retrieve account information plus a few fields from the customer. Lots of the logic ends up in helper classes, so the code becomes more structured (with entities used as old C structs). More boring scaffolding code, as there's no framework that extracts result sets from a stored procedure and puts it in an entity. My questions are: has anyone been in a similar situation and didn't agree with the store procedure approch? what did you do? Is there an actual benefit of using stored procedures? appart from the silly point of "no one can issue a drop table". Is there a way to create a rich domain using stored procedures? I know that there's the posibility of using AOP to inject DAOs/Repositories into entities to be able to navigate the object graph. I don't like this option as it's very close to voodoo.

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• What is Rainbow (not the CMS)

  - by Jeremy Thompson

  I was reading this excellent blog article regarding speeding up the badge page and in the last comment the author @waffles (a.k.a Sam Saffron) mentions these tools: dapper and a bunch of custom helpers like rainbow, sql builder etc Dapper and sql builder was easy to look up but rainbow keeps pointing me to a CMS, can someone please point me to the real source? Thanks. Obviously the architecture of these [SE] sites is uber cool and ultra fast so no comments on that thanks.

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• What are the advantages of myBatis over Hibernate?

  - by Kshitiz Sharma

  This question originates from a comment I received on one of my questions - I'd rather drop hibernate in favor of mybatis instead of jdbc I've done some research on my own and understand the basic concept. But some insights can only be gained through actual experience. What are the advantages of myBatis that would make it worth learning a new framework? In what case would you avoid using it?

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• How to get around the Circular Reference issue with JSON and Entity

  - by DanScan

  I have been experimenting with creating a website that leverages MVC with JSON for my presentation layer and Entity framework for data model/database. My Issue comes into play with serializing my Model objects into JSON. I am using the code first method to create my database. When doing the code first method a one to many relationship (parent/child) requires the child to have a reference back to the parent. (Example code my be a typo but you get the picture) class parent { public List<child> Children{get;set;} public int Id{get;set;} } class child { public int ParentId{get;set;} [ForeignKey("ParentId")] public parent MyParent{get;set;} public string name{get;set;} } When returning a "parent" object via a JsonResult a circular reference error is thrown because "child" has a property of class parent. I have tried the ScriptIgnore attribute but I lose the ability to look at the child objects. I will need to display information in a parent child view at some point. I have tried to make base classes for both parent and child that do not have a circular reference. Unfortunately when I attempt to send the baseParent and baseChild these are read by the JSON Parser as their derived classes (I am pretty sure this concept is escaping me). Base.baseParent basep = (Base.baseParent)parent; return Json(basep, JsonRequestBehavior.AllowGet); The one solution I have come up with is to create "View" Models. I create simple versions of the database models that do not include the reference to the parent class. These view models each have method to return the Database Version and a constructor that takes the database model as a parameter (viewmodel.name = databasemodel.name). This method seems forced although it works. NOTE:I am posting here because I think this is more discussion worthy. I could leverage a different design pattern to over come this issue or it could be as simple as using a different attribute on my model. In my searching I have not seen a good method to overcome this problem. My end goal would be to have a nice MVC application that heavily leverages JSON for communicating with the server and displaying data. While maintaining a consistant model across layers (or as best as I can come up with).

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• Classless tables possible with Datamapper?

  - by barerd

  I have an Item class with the following attributes: itemId,name,weight,volume,price,required_skills,required_items. Since the last two attributes are going to be multivalued, I removed them and create new schemes like: itemID,required_skill (itemID is foreign key, itemID and required_skill is primary key.) Now, I'm confused how to create/use this new table. Here are the options that came to my mind: 1) The relationship between Items and Required_skills is one-to-many, so I may create a RequiredSkill class, which belongs_to Item, which in turn has n RequiredSkills. Then I can do Item.get(1).requiredskills. This sounds most logical to me. 2) Since required_skills may well be thought of as constants (since they resemble rules), I may put them into a hash or gdbm database or another sql table and query from there, which I don't prefer. My question is: is there sth like a modelless table in datamapper, where datamapper is responsible from the creation and integrity of the table and allows me to query it in datamapper way, but does not require a class, like I may do it in sql?

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• OOP Design: relationship between entity classes

  - by beginner_

  I have at first sight a simple issue but can't wrap my head around on how to solve. I have an abstract class Compound. A Compound is made up of Structures. Then there is also a Container which holds 1 Compound. A "special" implementation of Compound has Versions. For that type of Compound I want the Container to hold the Versionof the Compound and not the Compound itself. You could say "just create an interface Containable" and a Container holds 1 Containable. However that won't work. The reason is I'm creating a framework and the main part of that framework is to simplify storing and especially searching for special data type held by Structure objects. Hence to search for Containers which contain a Compound made up of a specific Structure requires that the "Path" from Containerto Structure is well defined (Number of relationships or joins). I hope this was understandable. My question is how to design the classes and relationships to be able to do what I outlined.

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• Separating Db from business with Inherited classes using multiple views

  - by catalinux

  I have a software that has a car model that will be used in different views (listing, ads, detail page, carousel, up sell widget,etc). class CarModel extends DbModel{ } I look for a "nice way" (a combination of flexible, easy to maintain,etc) to have this used in views. I'm thinking at two different ways Having object views for each context CarViewBase{ var car;// of type CarModel function constructor(args){ //will instantienta internal variable car based on args } function getThumb(){ } function getTitle(){ } } CarListingView extends CarViewBase{ function getListing(){ } } CarAdsView extends CarViewBase{ //the busines rule changes for ads widget function getThumb(){ } } Extending directly the CarModel The challenges comes when My Car Model might need an abstract factory. Let's say I have a field on my car object that states the type of the car : a truck, or a bike, or van. How would affect that my object view? Let's say that getTitle() rule would be different for each type of it. How would you do it?

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• Should we have a database independent SQL like query language in Django? [closed]

  - by Yugal Jindle

  Note : I know we have Django ORM already that keeps things database independent and converts to the database specific SQL queries. Once things starts getting complicated it is preferred to write raw SQL queries for better efficiency. When you write raw sql queries your code gets trapped with the database you are using. I also understand its important to use the full power of your database that can-not be achieved with the django orm alone. My Question : Until I use any database specific feature, why should one be trapped with the database. For instance : We have a query with multiple joins and we decided to write a raw sql query. Now, that makes my website postgres specific. Even when I have not used any postgres specific feature. I feel there should be some fake sql language which can translate to any database's sql query. Even Django's ORM can be built over it. So, that if you go out of ORM but not database specific - you can still remain database independent. I asked the same question to Jacob Kaplan Moss (In person) : He advised me to stay with the database that I like and endure its whole power, to which I agree. But my point was not that we should be database independent. My point is we should be database independent until we use a database specific feature. Please explain, why should be there a fake sql layer over the actual sql ?

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• Using Propel ORM in my own custom classes

  - by Stick it to THE MAN

  I am refactoring a few classes I wrote a while ago, into my Symfony project (v1.3.2 with Propel ORM). The classes originally used direct connections to the database, I want to refactor those classes (stored in $(SF_LIB_DIR)) so that I can call propel and also use the ORM objects. To clarify, So for example, I want to be able to use code like this in my custom classes: try { $con = Propel::getConnection(); $c = new Criteria(); $foo = new PropelORMFooObject(); $foobar = PropelORMFooBarObjectPeer::fetch($c); //set fields etc $foo->setFooBar($foobar); // now save using obtained connection .. $foo->save($con) }catch(SomeException $e) { //deal with it } I assume that I will need to add some require_once() statements to my custom libraries, but it is not clear which files to include. Does anyone know how to do this?

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• Django ORM and multiprocessing

  - by Ankur Gupta

  Hi, I am using Django ORM in my python script in a decoupled fashion i.e. it's not running in context of a normal Django Project. I am also using the multi processing module. And different process in turn are making queries. The process ran successfully for an hr and exited with this message "IOError: [Errno 32] Broken pipe" Upon futhur diagnosis and debugging this error pops up when I call save() on the model instance. I am wondering Is Django ORM Process save ? Why would this error arise else ? Cheers Ankur

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• Entity Framework 5 vs Telerik OpenAccess ORM (specifically)

  - by dimoss

  I am starting a new project and want advice on choosing an ORM. I know this topic has been brought up before, but this topic is specific to either Entity Framework 5 (not 4) or Telerik OpenAccess ORM. The project will reside on Windows Azure and use Windows Azure SQL Database. I will migrate it to .NET 4.5 once 4.5 is live on Azure. I am currently a Telerik Ultimate Collection subscriber. Does anyone in the know have any pros/cons for this scenario? I am slightly leaning towards Telerik OpenAccess at the moment. Thanks

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• Kohana3 ORM save problem

  - by Bob0101

  Hi, Can anyone help me with Kohana ORM. I can take out name and value. I can give them new values and I try to save them back to base, but in phpmyadmin i can see still old values for these option attributes. What is wrong with this code (it works and echos right value but i can't see it in db): $option = ORM::factory('draft') ->where('user_id', '=', $user_id) ->find() ->draft_options ->where('name', '=', $_POST['name']) ->find(); $option->name = $_POST['name']; $option->value = $_POST['value']; $option->save(); if ($option->saved()) echo Kohana::debug($option->value);

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• Hibernate vs JPA vs JDO - pros and cons of each?

  - by matt b

  I'm familiar with ORM as a concept, and I've even used nHibernate several years ago for a .NET project; however, I haven't kept up with the topic of ORM in Java and haven't had a chance to use any of these tools. But, now I may have the chance to begin to use some ORM tools for one of our applications, in an attempt to move away from a series of legacy web services. I'm having a hard time telling the difference betweeen the JPA spec, what you get with the Hibernate library itself, and what JDO has to offer. So, I understand that this question is a bit open-ended, but I was hoping to get some opinions on: What are the pros and cons of each? Which would you suggest for a new project? Are there certain conditions when it would make sense to use one framework vs the other?

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• Kohana3 - ErrorException [ Notice ]: Undefined index: id - Error calling Auth::instance()

  - by ahmet2106

  Hello everybody, I've now a Problem with the newest Version of KohanaPHP (kohanaphp.com). After I've registered me and logged in into my test page, some minutes later, there is now the error: ErrorException [ Notice ]: Undefined index: id MODPATH/orm/classes/kohana/orm.php [ 1316 ] 1311 * 1312 * @return mixed primary key 1313 */ 1314 public function pk() 1315 { 1316 return $this->_object[$this->_primary_key]; 1317 } 1318 1319 /** 1320 * Returns whether or not primary key is empty 1321 * I've searched a lot in Google, but i never found an answer, the Problem now is, that I cant reloggin to get a new instance, because I've to call Auth::instance()-login() again, and Auth::instance() is not callable. Whats todo now, how can I fix it, is there already a new Version of ORM or Auth Module? Thanks everybody Ahmet

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• Use Google AppEngine datastore outside of AppEngine project

  - by Holtwick

  For my little framework Pyxer I would like to to be able to use the Google AppEngine datastores also outside of AppEngine projects, because I'm now used to this ORM pattern and for little quick hacks this is nice. I can not use Google AppEngine for all of my projects because of its's limitations in file size and number of files. A great alternative would also be, if there was a project that provides an ORM with the same naming as the AppEngine datastore. I also like the GQL approach very much, since this is a nice combination of ORM and SQL patterns. Any ideas where or how I might find such a solution? Thanks.

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• Empty dict-like collection problem in SQLAlchemy

  - by maksymko

  I have a mapping in SQLAlchemy that looks like this: t_property_value = sa.Table('property_value', MetaData, autoload = True, autoload_with = engine) orm.mapper(PropertyValue, t_property_value) t_estate = sa.Table('estate', MetaData, autoload = True, autoload_with = engine) orm.mapper(Estate, t_estate, properties = dict( property_hash = orm.relation(PropertyValue, collection_class = column_mapped_collection(t_property_value.c.property_id)) )) Now, everything seems to be fine, when I load the Estate object and it has some relations to PropertyValue objects. However, when it does not, then property_hash attribute is None, instead of being something dict-like, so I can not add new relations like this: estate.property_hash[prop_id] = PropertyValue(...) because I get the "'NoneType' object does not support item assignment" error. So, is there any way to force SQLAlchemy to create proper empty collection?

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• Use the Django ORM in a standalone script (again)

  - by Rishabh Manocha

  I'm trying to use the Django ORM in some standalone screen scraping scripts. I know this question has been asked before, but I'm unable to figure out a good solution for my particular problem. I have a Django project with defined models. What I would like to do is use these models and the ORM in my scraping script. My directory structure is something like this: project scrape #scraping scripts ... test.py web django_project settings.py ... #Django files I tried doing the following in project/scrape/test.py: print os.path.join(os.path.abspath('..'), 'web', 'django_project') sys.path.append(os.path.join(os.path.abspath('..'), 'web', 'django_project')) print sys.path print "-------" os.environ['DJANGO_SETTINGS_MODULE'] = 'django_project.settings' #print os.environ from django_project.myapp.models import MyModel print MyModel.objects.count() However, I get an ImportError when I try to run test.py: Traceback (most recent call last): File "test.py", line 12, in <module> from django_project.myapp.models import MyModel ImportError: No module named django_project.myapp.models One solution I found around this problem is to create a symbolic link to ../web/govcheck in the scrape folder: :scrape rmanocha$ ln -s ../web/govcheck ./govcheck With this, I can then run test.py just fine. However, this seems like a hack, and more importantly, is not very portable (I will have to create this symbolic link everywhere I run this code). So, I was wondering if anyone has any better solutions for my problem?

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