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  • Can I split an IEnumerable into two by a boolean criteria without two queries?

    - by SFun28
    Folks, Is it possible to split an IEnumerable into two IEnumerables using LINQ and only a single query/linq statement? In this way, I would avoid iterating through the IEnumerable twice. For example, is it possible to combine the last two statements below so allValues is only traversed once? IEnumerable<MyObj> allValues = ... List<MyObj> trues = allValues.Where( val => val.SomeProp ).ToList(); List<MyObj> falses = allValues.Where( val => !val.SomeProp ).ToList();

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  • MySQL create stored procedure fails but all internal queries succeed alone?

    - by Mark
    Hi all, I just created a simple database in MySQL, and I am learning how to write stored proc's. I'm familiar with M$SQL and as far as I can see the following should work: use mydb; -- -------------------------------------------------------------------------------- -- Routine DDL -- -------------------------------------------------------------------------------- DELIMITER // CREATE PROCEDURE mydb.doStats () BEGIN CREATE TABLE IF NOT EXISTS resultprobability ( ballNumber INT NOT NULL , probability FLOAT NULL, PRIMARY KEY (ballNumber) ); CREATE TABLE IF NOT EXISTS drawProbability ( drawDate DATE NOT NULL , ball1 INT NULL , ball2 INT NULL , ball3 INT NULL , ball4 INT NULL , ball5 INT NULL , ball6 INT NULL , ball7 INT NULL , score FLOAT NULL , PRIMARY KEY (drawDate) ); TRUNCATE TABLE resultprobability; TRUNCATE TABLE drawprobability; INSERT INTO resultprobability (ballNumber, probability) (select resultset.ballNumber ballNumber,(count(0)/(select count(0) from resultset)) probability from resultset group by resultset.ballNumber); INSERT INTO drawProbability (drawDate, ball1, ball2, ball3, ball4, ball5, ball6, ball7, score) (select distinct r.drawDate, a.ballnumber ball1, b.ballnumber ball2, c.ballnumber ball3, d.ballnumber ball4, e.ballnumber ball5, f.ballnumber ball6,g.ballnumber ball7, ((a.probability + b.probability + c.probability + d.probability + e.probability + f.probability + g.probability)/7) score from resultset r inner join (select r.drawDate, r.ballNumber, p.probability from resultset r inner join resultprobability p on p.ballNumber = r.ballNumber where r.appearence = 1) a on a.drawdate = r.drawDate inner join (select r.drawDate, r.ballNumber, p.probability from resultset r inner join resultprobability p on p.ballNumber = r.ballNumber where r.appearence = 2) b on b.drawdate = r.drawDate inner join (select r.drawDate, r.ballNumber, p.probability from resultset r inner join resultprobability p on p.ballNumber = r.ballNumber where r.appearence = 3) c on c.drawdate = r.drawDate inner join (select r.drawDate, r.ballNumber, p.probability from resultset r inner join resultprobability p on p.ballNumber = r.ballNumber where r.appearence = 4) d on d.drawdate = r.drawDate inner join (select r.drawDate, r.ballNumber, p.probability from resultset r inner join resultprobability p on p.ballNumber = r.ballNumber where r.appearence = 5) e on e.drawdate = r.drawDate inner join (select r.drawDate, r.ballNumber, p.probability from resultset r inner join resultprobability p on p.ballNumber = r.ballNumber where r.appearence = 6) f on f.drawdate = r.drawDate inner join (select r.drawDate, r.ballNumber, p.probability from resultset r inner join resultprobability p on p.ballNumber = r.ballNumber where r.appearence = 7) g on g.drawdate = r.drawDate order by score desc); END // DELIMITER ; instead i get the following Executed successfully in 0.002 s, 0 rows affected. Line 1, column 1 Error code 1064, SQL state 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 26 Line 6, column 1 Error code 1064, SQL state 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')) probability from resultset group by resultset.ballNumber); INSERT INTO d' at line 1 Line 31, column 51 Error code 1064, SQL state 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') score from resultset r inner join (select r.drawDate, r.ballNumber, p.probabi' at line 1 Line 39, column 114 Execution finished after 0.002 s, 3 error(s) occurred. What am I doing wrong? I seem to have exhausted my limited mental abilities!

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  • Get corresponding physical disk drives of mountpoints with WMI queries?

    - by Thomas
    Is there a way to retrieve a connection between a mountpoint (a volume which is mounted into the file system instead of mounted to a drive letter) and its belonging physical disk drive(s) with WMI? For example I have got a volume mountpoint on a W2K8 server which is mounted to “C:\Data\” and the mountpoint is spreaded on the physical disk drives 2, 4, and 5 of the server (the Data Management of the Server Manager shows that) but I cannot find a way to get this to know by using WMI. Volumes which have got a drive letter can be connected with the WMI-Classes Win32_DiskDrive -- Win32_DiskDriveToDiskPartition -- Win32_DiskPartition -- Win32_LogicalDiskToPartition -- Win32_LogicalDisk – but the problem is, that volume mountpoints aren’t listed in the class Win32_LogicalDisk, they are only listed in Win32_Volume. And I did not find a way to connect the class Win32_Volume with the class Win32_DiskDrive – there are missing some linking classes. Does anyone know a solution?

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  • Tuning Red Gate: #3 of Lots

    - by Grant Fritchey
    I'm drilling down into the metrics about SQL Server itself available to me in the Analysis tab of SQL Monitor to see what's up with our two problematic servers. In the previous post I'd noticed that rg-sql01 had quite a few CPU spikes. So one of the first things I want to check there is how much CPU is getting used by SQL Server itself. It's possible we're looking at some other process using up all the CPU Nope, It's SQL Server. I compared this to the rg-sql02 server: You can see that there is a more, consistently low set of CPU counters there. I clearly need to look at rg-sql01 and capture more specific data around the queries running on it to identify which ones are causing these CPU spikes. I always like to look at the Batch Requests/sec on a server, not because it's an indication of a problem, but because it gives you some idea of the load. Just how much is this server getting hit? Here are rg-sql01 and rg-sql02: Of the two, clearly rg-sql01 has a lot of activity. Remember though, that's all this is a measure of, activity. It doesn't suggest anything other than what it says, the number of requests coming in. But it's the kind of thing you want to know in order to understand how the system is used. Are you seeing a correlation between the number of requests and the CPU usage, or a reverse correlation, the number of requests drops as the CPU spikes? See, it's useful. Some of the details you can look at are Compilations/sec, Compilations/Batch and Recompilations/sec. These give you some idea of how the cache is getting used within the system. None of these showed anything interesting on either server. One metric that I like (even though I know it can be controversial) is the Page Life Expectancy. On the average server I expect see a series of mountains as the PLE climbs then drops due to a data load or something along those lines. That's not the case here: Those spikes back in January suggest that the servers weren't really being used much. The PLE on the rg-sql01 seems to be somewhat consistent growing to 3 hours or so then dropping, but the rg-sql02 PLE looks like it might be all over the map. Instead of continuing to look at this high level gathering data view, I'm going to drill down on rg-sql02 and see what it's done for the last week: And now we begin to see where we might have an issue. Memory on this system is getting flushed every 1/2 hour or so. I'm going to check another metric, scans: Whoa! I'm going back to the system real quick to look at some disk information again for rg-sql02. Here is the average disk queue length on the server: and the transfers Right, I think I have a guess as to what's up here. We're seeing memory get flushed constantly and we're seeing lots of scans. The disks are queuing, especially that F drive, and there are lots of requests that correspond to the scans and the memory flushes. In short, we've got queries that are scanning the data, a lot, so we either have bad queries or bad indexes. I'm going back to the server overview for rg-sql02 and check the Top 10 expensive queries. I'm modifying it to show me the last 3 days and the totals, so I'm not looking at some maintenance routine that ran 10 minutes ago and is skewing the results: OK. I need to look into these queries that are getting executed this much. They're generating a lot of reads, but which queries are generating the most reads: Ow, all still going against the same database. This is where I'm going to temporarily leave SQL Monitor. What I want to do is connect up to the server, validate that the Warehouse database is using the F:\ drive (which I'll put money down it is) and then start seeing what's up with these queries. Part 1 of the Series Part 2 of the Series

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  • Dissection of Google indexing services

    - by Pankaj Upadhyay
    There are more than a few questions that hop into mind when someone thinks about Google's indexing services. Jeff Atwood wrote about them at The Elephant in the Room: Google Monoculture and Trouble In the House of Google. I have two questions: How does google index dynamic websites? This site has dynamic pages, QUESTIONS, TAGS, USERS, BADGES, UNANSWERED, ASK QUESTION. The content of these pages is dynamically generated, therefore we access the dynamic content and not the physical files on the server. But how does Google shows every question of the site or other dynamic websites? What does Google index and keep on its servers? Does it copy the complete page into its server or just the title, meta tags and body?

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  • Goodbye XML&hellip; Hello YAML (part 2)

    - by Brian Genisio's House Of Bilz
    Part 1 After I explained my motivation for using YAML instead of XML for my data, I got a lot of people asking me what type of tooling is available in the .Net space for consuming YAML.  In this post, I will discuss a nice tooling option as well as describe some small modifications to leverage the extremely powerful dynamic capabilities of C# 4.0.  I will be referring to the following YAML file throughout this post Recipe: Title: Macaroni and Cheese Description: My favorite comfort food. Author: Brian Genisio TimeToPrepare: 30 Minutes Ingredients: - Name: Cheese Quantity: 3 Units: cups - Name: Macaroni Quantity: 16 Units: oz Steps: - Number: 1 Description: Cook the macaroni - Number: 2 Description: Melt the cheese - Number: 3 Description: Mix the cooked macaroni with the melted cheese Tooling It turns out that there are several implementations of YAML tools out there.  The neatest one, in my opinion, is YAML for .NET, Visual Studio and Powershell.  It includes a great editor plug-in for Visual Studio as well as YamlCore, which is a parsing engine for .Net.  It is in active development still, but it is certainly enough to get you going with YAML in .Net.  Start by referenceing YamlCore.dll, load your document, and you are on your way.  Here is an example of using the parser to get the title of the Recipe: var yaml = YamlLanguage.FileTo("Data.yaml") as Hashtable; var recipe = yaml["Recipe"] as Hashtable; var title = recipe["Title"] as string; In a similar way, you can access data in the Ingredients set: var yaml = YamlLanguage.FileTo("Data.yaml") as Hashtable; var recipe = yaml["Recipe"] as Hashtable; var ingredients = recipe["Ingredients"] as ArrayList; foreach (Hashtable ingredient in ingredients) { var name = ingredient["Name"] as string; } You may have noticed that YamlCore uses non-generic Hashtables and ArrayLists.  This is because YamlCore was designed to work in all .Net versions, including 1.0.  Everything in the parsed tree is one of two things: Hashtable, ArrayList or Value type (usually String).  This translates well to the YAML structure where everything is either a Map, a Set or a Value.  Taking it further Personally, I really dislike writing code like this.  Years ago, I promised myself to never write the words Hashtable or ArrayList in my .Net code again.  They are ugly, mostly depreciated collections that existed before we got generics in C# 2.0.  Now, especially that we have dynamic capabilities in C# 4.0, we can do a lot better than this.  With a relatively small amount of code, you can wrap the Hashtables and Array lists with a dynamic wrapper (wrapper code at the bottom of this post).  The same code can be re-written to look like this: dynamic doc = YamlDoc.Load("Data.yaml"); var title = doc.Recipe.Title; And dynamic doc = YamlDoc.Load("Data.yaml"); foreach (dynamic ingredient in doc.Recipe.Ingredients) { var name = ingredient.Name; } I significantly prefer this code over the previous.  That’s not all… the magic really happens when we take this concept into WPF.  With a single line of code, you can bind to the data dynamically in the view: DataContext = YamlDoc.Load("Data.yaml"); Then, your XAML is extremely straight-forward (Nothing else.  No static types, no adapter code.  Nothing): <StackPanel> <TextBlock Text="{Binding Recipe.Title}" /> <TextBlock Text="{Binding Recipe.Description}" /> <TextBlock Text="{Binding Recipe.Author}" /> <TextBlock Text="{Binding Recipe.TimeToPrepare}" /> <TextBlock Text="Ingredients:" FontWeight="Bold" /> <ItemsControl ItemsSource="{Binding Recipe.Ingredients}" Margin="10,0,0,0"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Quantity}" /> <TextBlock Text=" " /> <TextBlock Text="{Binding Units}" /> <TextBlock Text=" of " /> <TextBlock Text="{Binding Name}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> <TextBlock Text="Steps:" FontWeight="Bold" /> <ItemsControl ItemsSource="{Binding Recipe.Steps}" Margin="10,0,0,0"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Number}" /> <TextBlock Text=": " /> <TextBlock Text="{Binding Description}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </StackPanel> This nifty XAML binding trick only works in WPF, unfortunately.  Silverlight handles binding differently, so they don’t support binding to dynamic objects as of late (March 2010).  This, in my opinion, is a major lacking feature in Silverlight and I really hope we will see this feature available to us in Silverlight 4 Release.  (I am not very optimistic for Silverlight 4, but I can hope for the feature in Silverlight 5, can’t I?) Conclusion I still have a few things I want to say about using YAML in the .Net space including de-serialization and using IronRuby for your YAML parser, but this post is hopefully enough to see how easy it is to incorporate YAML documents in your code. Codeplex Site for YAML tools Dynamic wrapper for YamlCore

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  • SQL SERVER – How to Force New Cardinality Estimation or Old Cardinality Estimation

    - by Pinal Dave
    After reading my initial two blog posts on New Cardinality Estimation, I received quite a few questions. Once I receive this question, I felt I should have clarified it earlier few things when I started to write about cardinality. Before continuing this blog, if you have not read it before I suggest you read following two blog posts. SQL SERVER – Simple Demo of New Cardinality Estimation Features of SQL Server 2014 SQL SERVER – Cardinality Estimation and Performance – SQL in Sixty Seconds #072 Q: Does new cardinality will improve performance of all of my queries? A: Remember, there is no 0 or 1 logic when it is about estimation. The general assumption is that most of the queries will be benefited by new cardinality estimation introduced in SQL Server 2014. That is why the generic advice is to set the compatibility level of the database to 120, which is for SQL Server 2014. Q: Is it possible that after changing cardinality estimation to new logic by setting the value to compatibility level to 120, I get degraded performance for few queries? A: Yes, it is possible. However, the number of the queries where this impact should be very less. Q: Can I still run my database in older compatibility level and force few queries to newer cardinality estimation logic? If yes, How? A: Yes, you can do that. You will need to force your query with trace flag 2312 to use newer cardinality estimation logic. USE AdventureWorks2014 GO -- Old Cardinality Estimation ALTER DATABASE AdventureWorks2014 SET COMPATIBILITY_LEVEL = 110 GO -- Using New Cardinality Estimation SELECT [AddressID],[AddressLine1],[City] FROM [Person].[Address] OPTION(QUERYTRACEON 2312);; -- Using Old Cardinality Estimation SELECT [AddressID],[AddressLine1],[City] FROM [Person].[Address]; GO Q: Can I run my database in newer compatibility level and force few queries to older cardinality estimation logic? If yes, How? A: Yes, you can do that. You will need to force your query with trace flag 9481 to use newer cardinality estimation logic. USE AdventureWorks2014 GO -- NEW Cardinality Estimation ALTER DATABASE AdventureWorks2014 SET COMPATIBILITY_LEVEL = 120 GO -- Using New Cardinality Estimation SELECT [AddressID],[AddressLine1],[City] FROM [Person].[Address]; -- Using Old Cardinality Estimation SELECT [AddressID],[AddressLine1],[City] FROM [Person].[Address] OPTION(QUERYTRACEON 9481); GO I guess, I have covered most of the questions so far I have received. If I have missed any questions, please send me again and I will include the same. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • NDepend 4 – First Steps

    - by Ricardo Peres
    Introduction Thanks to Patrick Smacchia I had the chance to test NDepend 4. I can only say: awesome! This will be the first of a series of posts on NDepend, where I will talk about my discoveries. Keep in mind that I am just starting to use it, so more experienced users may find these too basic, I just hope I don’t say anything foolish! I must say that I am in no way affiliated with NDepend and I never actually met Patrick. Installation No installation program – a curious decision, I’m not against it -, just unzip the files to a folder and run the executable. It will optionally register itself with Visual Studio 2008, 2010 and 11 as well as RedGate’s Reflector; also, it automatically looks for updates. NDepend can either be used as a stand-alone program (with or without a GUI) or from within Visual Studio or Reflector. Getting Started One thing that really pleases me is the Getting Started section of the stand-alone, with links to pages on NDepend’s web site, featuring detailed explanations, which usually include screenshots and small videos (<5 minutes). There’s also an How do I with hierarchical navigation that guides us to through the major features so that we can easily find what we want. Usage There are two basic ways to use NDepend: Analyze .NET solutions, projects or assemblies; Compare two versions of the same assembly. I have so far not used NDepend to compare assemblies, so I will first talk about the first option. After selecting a solution and some of its projects, it generates a single HTML page with an highly detailed report of the analysis it produced. This includes some metrics such as number of lines of code, IL instructions, comments, types, methods and properties, the calculation of the cyclomatic complexity, coupling and lots of others indicators, typically grouped by type, namespace and assembly. The HTML also includes some nice diagrams depicting assembly dependencies, type and method relative proportions (according to the number of IL instructions, I guess) and assembly analysis relating to abstractness and stability. Useful, I would say. Then there’s the rules; NDepend tests the target assemblies against a set of more than 120 rules, grouped in categories Code Quality, Object Oriented Design, Design, Architecture and Layering, Dead Code, Visibility, Naming Conventions, Source Files Organization and .NET Framework Usage. The full list can be configured on the application, and an explanation of each rule can be found on the web site. Rules can be validated, violated and violated in a critical manner, and the HTML will contain the violated rules, their queries – more on this later - and results. The HTML uses some nice JavaScript effects, which allow paging and sorting of tables, so its nice to use. Similar to the rules, there are some queries that display results for a number (about 200) questions grouped as Object Oriented Design, API Breaking Changes (for assembly version comparison), Code Diff Summary (also for version comparison) and Dead Code. The difference between queries and rules is that queries are not classified as passes, violated or critically violated, just present results. The queries and rules are expressed through CQLinq, which is a very powerful LINQ derivative specific to code analysis. All of the included rules and queries can be enabled or disabled and new ones can be added, with intellisense to help. Besides the HTML report file, the NDepend application can be used to explore all analysis results, compare different versions of analysis reports and to run custom queries. Comparison to Other Analysis Tools Unlike StyleCop, NDepend only works with assemblies, not source code, so you can’t expect it to be able to enforce brackets placement, for example. It is more similar to FxCop, but you don’t have the option to analyze at the IL level, that is, other that the number of IL instructions and the complexity. What’s Next In the next days I’ll continue my exploration with a real-life test case. References The NDepend web site is http://www.ndepend.com/. Patrick keeps an updated blog on http://codebetter.com/patricksmacchia/ and he regularly monitors StackOverflow for questions tagged NDepend, which you can find on http://stackoverflow.com/questions/tagged/ndepend. The default list of CQLinq rules, queries and statistics can be found at http://www.ndepend.com/DefaultRules/webframe.html. The syntax itself is described at http://www.ndepend.com/Doc_CQLinq_Syntax.aspx and its features at http://www.ndepend.com/Doc_CQLinq_Features.aspx.

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  • SSAS DMVs: useful links

    - by Davide Mauri
    From time to time happens that I need to extract metadata informations from Analysis Services DMVS in order to quickly get an overview of the entire situation and/or drill down to detail level. As a memo I post the link I use most when need to get documentation on SSAS Objects Data DMVs: SSAS: Using DMV Queries to get Cube Metadata http://bennyaustin.wordpress.com/2011/03/01/ssas-dmv-queries-cube-metadata/ SSAS DMV (Dynamic Management View) http://dwbi1.wordpress.com/2010/01/01/ssas-dmv-dynamic-management-view/ Use Dynamic Management Views (DMVs) to Monitor Analysis Services http://msdn.microsoft.com/en-us/library/hh230820.aspx

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  • MySQL & PHP - select/option lists and showing data to users that still allows me to generate queries

    - by Andrew Heath
    Sorry for the unclear title, an example will clear things up: TABLE: Scenario_victories ID scenid timestamp userid side playdate 1 RtBr001 2010-03-15 17:13:36 7 1 2010-03-10 2 RtBr001 2010-03-15 17:13:36 7 1 2010-03-10 3 RtBr001 2010-03-15 17:13:51 7 2 2010-03-10 ID and timestamp are auto-insertions by the database when the other 4 fields are added. The first thing to note is that a user can record multiple playings of the same scenario (scenid) on the same date (playdate) possibly with the same outcome (side = winner). Hence the need for the unique ID and timestamps for good measure. Now, on their user page, I'm displaying their recorded play history in a <select><option>... list form with 2 buttons at the end - Delete Record and Go to Scenario My script takes the scenid and after hitting a few other tables returns with something more user-friendly like: (playdate) (from scenid) (from side) ######################################################### # 2010-03-10 Road to Berlin #1 -- Germany, Hungary won # # 2010-03-10 Road to Berlin #1 -- Germany, Hungary won # # 2010-03-10 Road to Berlin #1 -- Soviet Union won # ######################################################### [Delete Record] [Go To Scenario] in HTML: <select name="history" size=3> <option>2010-03-10 Road to Berlin #1 -- Germany, Hungary won</option> <option>2010-03-10 Road to Berlin #1 -- Germany, Hungary won</option> <option>2010-03-10 Road to Berlin #1 -- Soviet Union won</option> </select> Now, if you were to highlight the first record and click Go to Scenario there is enough information there for me to parse it and produce the exact scenario you want to see. However, if you were to select Delete Record there is not - I have the playdate and I can parse the scenid and side from what's listed, but in this example all three records would have the same result. I appear to have painted myself into a corner. Does anyone have a suggestion as to how I can get some unique identifying data (ID and/or timestamp) to ride along on this form without showing it to the user? PHP-only please, I must be NoScript compliant!

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  • How can I speed up queries against tables I cannot add indexes to?

    - by RenderIn
    I access several tables remotely via DB Link. They are very normalized and the data in each is effective-dated. Of the millions of records in each table, only a subset of ~50k are current records. The tables are internally managed by a commercial product that will throw a huge fit if I add indexes or make alterations to its tables in any way. What are my options for speeding up access to these tables?

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  • Complex Rails queries across multiple tables, unions, and will_paginate. Solved.

    - by uberllama
    Hi folks. I've been working on a complex "user feed" type of functionality for a while now, and after experimenting with various union plugins, hacking named scopes, and brute force, have arrived at a solution I'm happy with. S.O. has been hugely helpful for me, so I thought I'd post it here in hopes that it might help others and also to get feedback -- it's very possible that I worked on this so long that I walked down an unnecessarily complicated road. For the sake of my example, I'll use users, groups, and articles. A user can follow other users to get a feed of their articles. They can also join groups and get a feed of articles that have been added to those groups. What I needed was a combined, pageable feed of distinct articles from a user's contacts and groups. Let's begin. user.rb has_many :articles has_many :contacts has_many :contacted_users, :through => :contacts has_many :memberships has_many :groups, :through => :memberships contact.rb belongs_to :user belongs_to :contacted_user, :class_name => "User", :foreign_key => "contacted_user_id" article.rb belongs_to :user has_many :submissions has_many :groups, :through => :submissions group.rb has_many :memberships has_many :users, :through => :memberships has_many :submissions has_many :articles, :through => :submissions Those are the basic models that define my relationships. Now, I add two named scopes to the Article model so that I can get separate feeds of both contact articles and group articles should I desire. article.rb # Get all articles by user's contacts named_scope :by_contacts, lambda {|user| {:joins => "inner join contacts on articles.user_id = contacts.contacted_user_id", :conditions => ["articles.published = 1 and contacts.user_id = ?", user.id]} } # Get all articles in user's groups. This does an additional query to get the user's group IDs, then uses those in an IN clause named_scope :by_groups, lambda {|user| {:select => "DISTINCT articles.*", :joins => :submissions, :conditions => {:submissions => {:group_id => user.group_ids}}} } Now I have to create a method that will provide a UNION of these two feeds into one. Since I'm using Rails 2.3.5, I have to use the construct_finder_sql method to render a scope into its base sql. In Rails 3.0, I could use the to_sql method. user.rb def feed "(#{Article.by_groups(self).send(:construct_finder_sql,{})}) UNION (#{Article.by_contacts(self).send(:construct_finder_sql,{})})" end And finally, I can now call this method and paginate it from my controller using will_paginate's paginate_by_sql method. HomeController.rb @articles = Article.paginate_by_sql(current_user.feed, :page => 1) And we're done! It may seem simple now, but it was a lot of work getting there. Feedback is always appreciated. In particular, it would be great to get away from some of the raw sql hacking. Cheers.

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  • How to search phrase queries in inverted index structure?

    - by Mehdi Amrollahi
    If we want to search a query like this "t1 t2 t3" (t1,t2 ,t3 must be queued) in an inverted index structure , which ways could we do ? 1-First we search the "t1" term and find all documents that contains "t1" , then do this work for "t2" and then "t3" . Then find documents that positions of "t1" , "t2" and "t3" are next to each other . 2-First we search the "t1" term and find all documents that contains "t1" , then in all documents that we found , we search the "t2" and next , in the result of this , we find documents that contains "t3" . thanks .

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  • Adventures in MVVM &ndash; My ViewModel Base &ndash; Silverlight Support!

    - by Brian Genisio's House Of Bilz
    More Adventures in MVVM In my last post, I outlined the powerful features that are available in the ViewModelSupport.  It takes advantage of the dynamic features of C# 4.0 (as well as some 3.0 goodies) to help eliminate the plumbing that often comes with writing ViewModels.  If you are interested in learning about the capabilities, please take a look at that post and look at the code on CodePlex.  When I wrote about the ViewModel base class, I complained that the features did not work in Silverlight because as of 4.0, it does not support binding to dynamic properties.  Although I still think this is a bummer, I am happy to say that I have come up with a workaround.  In the Silverlight version of my base class, I include a PropertyCollectionConverter that lets you bind to dynamic properties in the ViewModelBase, especially the convention-based commands that the base class supports. To take advantage of any properties that are not statically defined, you can bind to the Properties property of the ViewModel and pass in a converter parameter for the name of the property you want to bind. For example, a ViewModel that looks like this: public class ExampleViewModel : ViewModelBase { public void Execute_MyCommand() { Set("Text", "Foo"); } } Can bind to the dynamic property and the convention-based command with the following XAML. <TextBlock Text="{Binding Properties, Converter={StaticResource PropertiesConverter}, ConverterParameter=Text}" Margin="5" /> <Button Content="Execute MyCommand" Command="{Binding Properties, Converter={StaticResource PropertiesConverter}, ConverterParameter=MyCommand}" Margin="5" /> Of course, it is not as pretty as binding to Text and MyCommand like you can in WPF.  But, it is better than having a failed feature.  This allows you to share your ViewModels between WPF and Silverlight very easily.  <BeatDeadHorse>Hopefully, in Silverlight 5.0, we will see binding to dynamic properties more directly????</BeatDeadHorse>

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  • fitnesse test framework, arbitrary properties for test and queries/test runs based on them?

    - by Marcel
    hi, our testers have the requirement to store multiple properties for a test that are not present in the "properties". e.g. they want to store priority, a description(not in the wiki page itself) and so on. they don't want to use the tagging mechanism. is there a way to store any kind of new xml node in the properties.xml for a test? these properties should then be used to: query the fields via the search screen run tests based on the "SuiteResponder" ?suite=xxx&TAGx=abc&TAGy=cde they should be returned by "?properties" responder. they should appear in the test history of the test run in essence they want to store any kind of "meta" information in the properties.xml and work with them in all kinds of ways, search, run etc. does anybody here know if there is already something available in that direction? if not i think we have to "pimp" these features into fitnesse to make our testers happy. thanks a lot any help appreciated marcel ps: i've also posted the question in the yahoo fitnesse group

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  • How do I improve the efficiency of the queries executed by this generic Linq-to-SQL data access clas

    - by Lee D
    Hi all, I have a class which provides generic access to LINQ to SQL entities, for example: class LinqProvider<T> //where T is a L2S entity class { DataContext context; public virtual IEnumerable<T> GetAll() { return context.GetTable<T>(); } public virtual T Single(Func<T, bool> condition) { return context.GetTable<T>().SingleOrDefault(condition); } } From the front end, both of these methods appear to work as you would expect. However, when I run a trace in SQL profiler, the Single method is executing what amounts to a SELECT * FROM [Table], and then returning the single entity that meets the given condition. Obviously this is inefficient, and is being caused by GetTable() returning all rows. My question is, how do I get the query executed by the Single() method to take the form SELECT * FROM [Table] WHERE [condition], rather than selecting all rows then filtering out all but one? Is it possible in this context? Any help appreciated, Lee

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  • Project of Projects with team Foundation Server 2010

    - by Martin Hinshelwood
    It is pretty much accepted that you should use Areas instead of having many small Team Projects when you are using Team Foundation Server 2010. I have implemented this scenario many times and this is the current iteration of layout and considerations. If like me you work with many customers you will find that you get into a grove for how to set these things up to make them as easily understandable for everyone, while giving the best functionality. The trick is in making it as intuitive as possible for both you and the developers that need to work with it. There are five main places where you need to have the Product or Project name in prominence of any other value. Area Iteration Source Code Work Item Queries Build Once you decide how you are doing this in each of these places you need to keep to it religiously. Evan if you have one source code file to keep, make sure it is in the right place. This makes your developers and others working with the format familiar with where everything should go, as well as building up mussel memory. This prevents the neat system degenerating into a nasty mess. Areas Areas are traditionally used to separate out parts of your product / project so that you can see how much effort has gone into each. Figure: The top level areas are for reporting and work item separation There are massive advantages of using this method. You can: move work from one project to another rename a project / product It is far more likely that a project or product gets renamed than a department. Tip: If you have many projects, over 100, you should consider categorising them here, but make sure that the actual project name always sits at the same level so you know which is which. Figure: Always keep things that are the same at the same level Note: You may use these categories only at the Area/Iteration level to make it easier to select on drop down lists. You may not want to use them everywhere. On the other hand, for consistency it would be better to. Iterations Iterations are usually used to some sort of time based consideration. Here I am splitting into Iterations with periodic releases. Figure: Each product needs to be able to have its own cadence The ability to have each project run at its own pace and to enable them to have their own release schedule is often of paramount importance and you don’t want to fix your 100+ projects to all be released on the same date. Source Code Having a good structure for your source even if you are not branching or having multiple products under the same structure is always a good idea. Figure: Separate out your products source You need to think about both your branches as well as the structure of your source. All your code should be under “Source” and everything you need to build your solution including Build Scripts and 3rd party tools should be under your “Main” (branch) folder. This should them be branched by “Quality”, “Release” or both to get the most out of your branching structure. The important thing is to make sure you branch (or be able to branch) everything you need to build, test and deploy your application to an environment. That environment may be development, test or even production, but I can’t stress the importance of having everything your need. Note: You usually will not be able to install custom software on your build server. Store any *.dll’s or *.exe’s that you need under the “Tools\Tool1” folder. Note: Consult the Branching Guidance for Team Foundation Server 2010 for more on branching Figure: Adding category may be a necessary evil Even if you have to have a couple of categories called “Default”, it is better than not knowing the difference between a folder, Product and Branch. Work Item Queries Queries are used to load lists of Work Items out of TFS so you can see what work you have. This means that you want to also separate queries out by Product / project to make it easier to Figure: Again you have the same first level structure Having Folders also in Work Item Tracking we do the same thing. We put all the queries under a folder named for the Product / Project and change each query to have “AreaPath=[TeamProject]\[ProductX]” in the query instead of the standard “Project=@Project”. Tip: Don’t have a folder with new queries for each iteration. Instead have a single “Current” folder that has queries that point to the current iteration. Just change the queries as you move from one iteration to another. Tip: You can ctrl+drag the “Product1” folder to create your “Product2” folder. Builds You may have many builds both for individual products but also for different quality's. This can be further complicated by having some builds that action “Gated Check-In” and others that are specifically for “Release”, “Test” or another purpose. Figure: There are no folders, yet, for the builds so you need a good naming convention Its a pity that there are no folders under builds, some way to categorise would be nice. In lue of that at the moment you can use a functional naming convention that at least allows you to find what you want. Conclusion It is really easy to both achieve and to stick to this format if you take the time to do it. Unless you have 1000+ builds or 100+ Products you are unlikely run into any issues. Even then there are things you can do to mitigate the issues and I have describes some of them above. Let me know if you can think of any other things to make this easier.

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  • Are any of these SQL Queries open to SQL injection attacks?

    - by Phil
    I have re-written my code after great help from some friendly stack overflow members (big thanks to Martin B and Kev Chadders especially). I would now like to check if my code is still open to SQL Injections after this work. I believe the code is now working as it should, but any blinding errors that you see i'd love to hear about too. My code is now looking like: -code removed-

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  • How to use function to connect to database and how to work with queries?

    - by Abhilash Shukla
    I am using functions to work with database.. Now the way i have defined the functions are as follows:- /** * Database definations */ define ('db_type', 'MYSQL'); define ('db_host', 'localhost'); define ('db_port', '3306'); define ('db_name', 'database'); define ('db_user', 'root'); define ('db_pass', 'password'); define ('db_table_prefix', ''); /** * Database Connect */ function db_connect($host = db_host, $port = db_port, $username = db_user, $password = db_pass, $database = db_name) { if(!$db = @mysql_connect($host.':'.$port, $username, $password)) { return FALSE; } if((strlen($database) > 0) AND (!@mysql_select_db($database, $db))) { return FALSE; } // set the correct charset encoding mysql_query('SET NAMES \'utf8\''); mysql_query('SET CHARACTER_SET \'utf8\''); return $db; } /** * Database Close */ function db_close($identifier) { return mysql_close($identifier); } /** * Database Query */ function db_query($query, $identifier) { return mysql_query($query, $identifier); } Now i want to know whether it is a good way to do this or not..... Also, while database connect i am using $host = db_host Is it ok? Secondly how i can use these functions, these all code is in my FUNCTIONS.php The Database Definitions and also the Database Connect... will it do the needful for me... Using these functions how will i be able to connect to database and using the query function... how will i able to execute a query? VERY IMPORTANT: How can i make mysql to mysqli, is it can be done by just adding an 'i' to mysql....Like:- @mysql_connect @mysqli_connect

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  • How to handle pagination queries properly with mongodb and php?

    - by luckytaxi
    Am I doing this right? I went to look at some old PHP code w/ MySQL and I've managed to get it to work, however I'm wondering if there's a much "cleaner" and "faster" way of accomplishing this. First I would need to get the total number of "documents" $total_documents = $collection->find(array("tags" => $tag, "seeking" => $this->session->userdata('gender'), "gender" => $this->session->userdata('seeking')))->count(); $skip = (int)($docs_per_page * ($page - 1)); $limit = $docs_per_page; $total_pages = ceil($total_documents / $limit); // Query to populate array so I can display with pagination $data['result'] = $collection->find(array("tags" => $tag, "seeking" => $this->session->userdata('gender'), "gender" => $this->session->userdata('seeking')))->limit($limit)->skip($skip)->sort(array("_id" => -1)); My question is, can I run the query in one shot? I'm basically running the same query twice, except the second time I'm passing the value to skip between records.

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  • Use CompiledQuery.Compile to improve LINQ to SQL performance

    - by Michael Freidgeim
    After reading DLinq (Linq to SQL) Performance and in particular Part 4  I had a few questions. If CompiledQuery.Compile gives so much benefits, why not to do it for all Linq To Sql queries? Is any essential disadvantages of compiling all select queries? What are conditions, when compiling makes whose performance, for how much percentage? World be good to have default on application config level or on DBML level to specify are all select queries to be compiled? And the same questions about Entity Framework CompiledQuery Class. However in comments I’ve found answer  of the author ricom 6 Jul 2007 3:08 AM Compiling the query makes it durable. There is no need for this, nor is there any desire, unless you intend to run that same query many times. SQL provides regular select statements, prepared select statements, and stored procedures for a reason.  Linq now has analogs. Also from 10 Tips to Improve your LINQ to SQL Application Performance   If you are using CompiledQuery make sure that you are using it more than once as it is more costly than normal querying for the first time. The resulting function coming as a CompiledQuery is an object, having the SQL statement and the delegate to apply it.  And your delegate has the ability to replace the variables (or parameters) in the resulting query. However I feel that many developers are not informed enough about benefits of Compile. I think that tools like FxCop and Resharper should check the queries  and suggest if compiling is recommended. Related Articles for LINQ to SQL: MSDN How to: Store and Reuse Queries (LINQ to SQL) 10 Tips to Improve your LINQ to SQL Application Performance Related Articles for Entity Framework: MSDN: CompiledQuery Class Exploring the Performance of the ADO.NET Entity Framework - Part 1 Exploring the Performance of the ADO.NET Entity Framework – Part 2 ADO.NET Entity Framework 4.0: Making it fast through Compiled Query

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