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• How do I do MongoDB console-style queries in PHP?

  - by Zoe Boles

  I'm trying to get a MongoDB query from the javascript console into my PHP app. What I'm trying to avoid is having to translate the query into the PHP "native driver"'s format... I don't want to hand build arrays and hand-chain functions any more than I want to manually build an array of MySQL's internal query structure just to get data. I already have a string producing the exact content I want in the Mongo console: db.intake.find({"processed": {"$exists": "false"}}).sort({"insert_date": "1"}).limit(10); The question is, is there a way for me to hand this string, as is, to MongoDB and have it return a cursor with the dataset I request? Right now I'm at the "write your own parser because it's not valid json to kinda turn a subset of valid Mongo queries into the format the PHP native driver wants" state, which isn't very fun. I don't want an ORM or a massive wrapper library; I just want to give a function my query string as it exists in the console and get an Iterator back that I can work with. I know there are a couple of PHP-based Mongo manager applications that apparently take console-style queries and handle them, but initial browsing through their code, I'm not sure how they handle the translation. I absolutely love working with mongo in the console, but I'm rapidly starting to loathe the thought of converting every query into the format the native writer wants...

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• Odd 'UNION' behavior in an Oracle SQL query

  - by RenderIn

  Here's my query: SELECT my_view.* FROM my_view WHERE my_view.trial in (select 2 as trial_id from dual union select 3 from dual union select 4 from dual) and my_view.location like ('123-%') When I execute this query it returns results which do not conform to the my_view.location like ('123-%') condition. It's as if that condition is being ignored completely. I can even change it to my_view.location IS NULL and it returns the same results, despite that field being not-nullable. I know this query seems ridiculous with the selects from dual, but I've structured it this way to replicate a problem I have when I use a 'WITH' clause (the results of that query are where the selects from dual inline view are). I can modify the query like so and it returns the expected results: SELECT my_view.* FROM my_view WHERE my_view.trial in (2, 3, 4) and my_view.location like ('123-%') Unfortunately I do not know the trial values up front (they are queried for in a 'WITH' clause) so I cannot structure my query this way. What am I doing wrong? I will say that the my_view view is composed of 3 other views whose results are UNION ALL and each of which retrieve some data over a DB Link. Not that I believe that should matter, but in case it does.

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• Effective Method to Manage and Search Through 100,000+ Objects Instantly? (C#)

  - by Kirk

  I'm writing a media player for enthusiasts with large collections (over 100,000 tracks) and one of my main goals is speed in search. I would like to allow the user to perform a Google-esque search of their entire music collection based on these factors: Song Path and File Name Items in ID3 Tag (Title, Artist, Album, etc.) Lyrics What is the best way for me to store this data and search through it? Currently I am storing each track in an object and iterating over an array of these objects checking each of their variables for string matches based on given search text. I've run into problems though where my search is not effective because it is always a phrase search and I'm not sure how to make it more fuzzy. Would an internal DB like SQLlite be faster than this? Any ideas on how I should structure this system? I also need playlist persistence, so that when they close the app and open the app their same playlist loads immediately. How should I store the playlist information so it can load quickly when the application starts? Currently I am JSON encoding the entire playlist, storing it in a text file, and reading it into the ListView at runtime, but it is getting sluggish over 20,000 tracks. Thanks!

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• MYSQL - SELECT ALL FROM TABLE if...

  - by hornetbzz

  Hello I have a (nice) mysql table built like this : Fields Datas id (pk) 1 2 3 4 5 6 master_id 1000 1000 1000 2000 2000 2000 ... master_name home home home shop shop shop ... type_data value common client value common client ... param_a foo_a 1 0 bar_a 0 1 ... param_b foo_b 1 0 bar_b 1 0 ... param_c foo_c 0 1 bar_c 0 1 ... ... ... ... ... ... ... ... ... All these datas are embed in a single table. Each datas are dispatched on 3 "columns" set (1 for the values, 1 for identifying if these are common values and one for identifying client values). It's not the best I got but many other scripts depends on this structure. I'd need sthg like this: SELECT parameters name (eg param_a, param_b..) and their values (eg foo_a, foo_b..) WHEN master_id=? AND type_data=(common or client) (eg for values=1 on the 2nd column) . in order to get the parameters hash like param_a => foo_a param_b => foo_b param_c => foo_c ... I could not succeed in self joining on the same table till now but I guess it should be feasible. (I'd like to avoid to do several queries) Thx in advance

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• Query broke down and left me stranded in the woods

  - by user1290323

  I am trying to execute a query that deletes all files from the images table that do not exist in the filters tables. I am skipping 3,500 of the latest files in the database as to sort of "Trim" the table back to 3,500 + "X" amount of records in the filters table. The filters table holds markers for the file, as well as the file id used in the images table. The code will run on a cron job. My Code: $sql = mysql_query("SELECT * FROM `images` ORDER BY `id` DESC") or die(mysql_error()); while($row = mysql_fetch_array($sql)){ $id = $row['id']; $file = $row['url']; $getId = mysql_query("SELECT `id` FROM `filter` WHERE `img_id` = '".$id."'") or die(mysql_error()); if(mysql_num_rows($getId) == 0){ $IdQue[] = $id; $FileQue[] = $file; } } for($i=3500; $i<$x; $i++){ mysql_query("DELETE FROM `images` WHERE id='".$IdQue[$i]."' LIMIT 1") or die("line 18".mysql_error()); unlink($FileQue[$i]) or die("file Not deleted"); } echo ($i-3500)." files deleted."; Output: 0 files deleted. Database contents: images table: 10,000 rows filters table: 63 rows Amount of rows in filters table that contain an images table id: 63 Execution time of php script: 4 seconds +/- 0.5 second Relevant DB structure TABLE: images id url etc... TABLE: filter id img_id (CONTAINS ID FROM images table) etc...

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• JSF: Avoid nested update calls

  - by dhroove

  I don't know if I am on right track or not still asking this question. I my JSF project I have this tree structure: <p:tree id="resourcesTree" value="#{someBean.root}" var="node" selectionMode="single" styleClass="no-border" selection="#{someBean.selectedNode}" dynamic="true"> <p:ajax listener="#{someBean.onNodeSelect}" update=":centerPanel :tableForm :tabForm" event="select" onstart="statusDialog.show();" oncomplete="statusDialog.hide();" /> <p:treeNode id="resourcesTreeNode" > <h:outputText value="#{node}" id="lblNode" /> </p:treeNode> </p:tree> I have to update this tree after I added something or delete something.. But whenever I update this still its nested update also call I mean to say it also call to update these components ":centerPanel :tableForm :tabForm"... This give me error that :tableForm not found in view because this forms load in my central panel and this tree is in my right panel.. So when I am doing some operation on tree is it not always that :tableForm is in my central panel.. (I mean design is something like this only) So now my question is that can I put some condition or there is any way so that I can specify when to update nested components also and when not.... In nut shell is there any way to update only :resoucesTree is such a way that nested updates are not called so that I can avoid error... Thanks in advance.

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• Java inheritance and super() isn't working as expected

  - by dwwilson66

  For a homework assignment, I'm working with the following. It's an assigned class structure, I know it's not the best design by a long shot. Class | Extends | Variables -------------------------------------------------------- Person | None | firstName, lastName, streetAddress, zipCode, phone CollegeEmployee | Person | ssn, salary,deptName Faculty | CollegeEmployee | tenure(boolean) Student | person | GPA,major So in the Faculty class... public class Faculty extends CollegeEmployee { protected String booleanFlag; protected boolean tenured; public Faculty(String firstName, String lastName, String streetAddress, String zipCode, String phoneNumber,String ssn, String department,double salary) { super(firstName,lastName,streetAddress,zipCode,phoneNumber, ssn,department,salary); String booleanFlag = JOptionPane.showInputDialog (null, "Tenured (Y/N)?"); if(booleanFlag.equals("Y")) tenured = true; else tenured = false; } } It was my understanding that super() in Faculty would allow access to the variables in CollegeEmployee as well as Person. With the code above, it compiles fine when I ONLY include the Person variables. As soon as I try to use ssn, department, or salary I get the following compile errors. Faculty.java:15: error: constructor CollegeEmployee in class CollegeEmployee can not be applied to the given types: super(firstName,lastName,streetAddress,zipCode,phoneNumber,ssn,department,salary); ^ Required: String,String,String,String,String Found: String,String,String,String,String,String,String,String reason: actual and formal argument lists differ in length I'm completely confused by this error...which is the actual and formal? Person has five arguments, CollegeEmployee has 3, so my guess is that something's funky with how the parameters are being passed...but I'm not quite sure where to begin fixing it. What am I missing?

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• Need help with a SQL CTE Query

  - by Chuck

  I have a table that I need to get some specific data from for a view. Here's the base table structure with some sample data: | UserID | ReportsToUserID | Org ID | ------------------------------------- | 1 | NULL | 1 | ------------------------------------- | 2 | 1 | 1 | ------------------------------------- | 3 | 2 | 1 | ------------------------------------- | 4 | 3 | 1 | ------------------------------------- The users will be entering reports and users can see the reports of users who report to them and any users who report to those users. Users who report to no one can see everything in their organization Given my sample data above, user 1 can see the reports of 2, 3, & 4; user 2 can see the reports of 3 & 4; and user 3 can see the reports of 4. For the view, I'd like to have the data returned as follows: | UserID | CanSeeUserID | OrgID | -------------------------------------------- | 1 | 2 | 1 | -------------------------------------------- | 1 | 3 | 1 | -------------------------------------------- | 1 | 4 | 1 | -------------------------------------------- | 2 | 3 | 1 | -------------------------------------------- etc... Below is my current code, any help is greatly appreciated. WITH CTEUsers (UserID, CanSeeUserID, OrgID) AS ( SELECT e.ID, e.ReportsToUserID, e.OrgID FROM Users e WITH(NOLOCK) WHERE COALESCE(ReportsToUserID,0) = 0 --ReportsToUserID can be NULL or 0 UNION ALL SELECT e.ReportsToUserID, e.ID,e.OrgID FROM Users e WITH(NOLOCK) JOIN CTEUsers c ON e.ID = c.UserID ) SELECT * FROM CTEUsers

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• How to render an HTML attribute from a Razor view.

  - by ProfK

  I would like to use the same partial view for create, edit, and details views, to avoid duplicating the fieldset structure for an entity. Then, depending on which view renders the partial view, I would like to add a class of "read-only" to a div surrounding my fieldset and handle making the actual input fields read-only on the client, using css or jQuery, or whatever. How can I specify from my Razor view that I need this class added to the "item-details" div? <div class="item-details"> <fieldset> <legend>Product Details</legend> @Html.HiddenFor(model => model.DetailItem.ProductId) <div class="editor-label"> @Html.LabelFor(model => model.DetailItem.Name) </div> <div class="editor-field"> @Html.EditorFor(model => model.DetailItem.Name) @Html.ValidationMessageFor(model => model.DetailItem.Name) </div> <p> <input type="submit" value="Save" /> </p> </fieldset> </div>

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• Problems with Json Serialize Dictionary<Enum, Int32>

  - by dbemerlin

  Hi, whenever i try to serialize the dictionary i get the exception: System.ArgumentException: Type 'System.Collections.Generic.Dictionary`2[[Foo.DictionarySerializationTest+TestEnum, Foo, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' is not supported for serialization/deserialization of a dictionary, keys must be strings or object My Testcase is: public class DictionarySerializationTest { private enum TestEnum { A, B, C } public void SerializationTest() { Dictionary<TestEnum, Int32> data = new Dictionary<TestEnum, Int32>(); data.Add(TestEnum.A, 1); data.Add(TestEnum.B, 2); data.Add(TestEnum.C, 3); JavaScriptSerializer serializer = new JavaScriptSerializer(); String result = serializer.Serialize(data); // Throws } public void SerializationStringTest() { Dictionary<String, Int32> data = new Dictionary<String, Int32>(); data.Add(TestEnum.A.ToString(), 1); data.Add(TestEnum.B.ToString(), 2); data.Add(TestEnum.C.ToString(), 3); JavaScriptSerializer serializer = new JavaScriptSerializer(); String result = serializer.Serialize(data); // Succeeds } } Of course i could use .ToString() whenever i enter something into the Dictionary but since it's used quite often in performance relevant methods i would prefer using the enum. My only solution is using .ToString() and converting before entering the performance critical regions but that is clumsy and i would have to change my code structure just to be able to serialize the data. Does anyone have an idea how i could serialize the dictionary as <Enum, Int32>? I use the System.Web.Script.Serialization.JavaScriptSerializer for serialization.

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• XSLT line counter - is it that hard?

  - by Mr AH

  I have cheated every time I've needed to do a line count in XSLT by using JScript, but in this case I can't do that. I simply want to write out a line counter throughout an output file. This basic example has a simple solution: <xsl:for-each select="Records/Record"> <xsl:value-of select="position()"/> </xsl:for-each> Output would be: 1 2 3 4 etc... But what if the structure is more complex with nested foreach's : <xsl:for-each select="Records/Record"> <xsl:value-of select="position()"/> <xsl:for-each select="Records/Record"> <xsl:value-of select="position()"/> </xsl:for-each> </xsl:for-each> Here, the inner foreach would just reset the counter (so you get 1, 1, 2, 3, 2, 1, 2, 3, 1, 2 etc). Does anyone know how I can output the position in the file (ie. a line count)?

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• Response.Redirect not firing due to code to prevent re-submission

  - by Marco

  I have an event which needs to contact some third party providers before performing a redirect (think 'final payment page on ecommerce site') and hence has some lag associated with its processing. It is very important that these third party providers are not contacted more than once, and sometimes impatient users may try and refresh the page (hence re-submitting the data). The general code structure is: If Session("orderStatus") <> 'processing' Then Session("orderStatus") = 'processing' DoThirdPartyStuffThatTakesSomeTime() Response.Redirect("confirmationPage.asp", True) End If The problem is, if the user refreshes the page, the response.redirect does not happen (even though the rest of the code will run before the redirect from the original submission). It seems that the new submission creates a new thread for the browser which takes precedence - it skips this bit of code obviously to prevent the third party providers being contacted a second time, and since there is no redirect, just comes back to the same page. The whole second submission may have completed before the first submission has finished its job. Any help on how I can still ignore all of the subsequent submissions of the page, but still make the redirect work...? Thanks

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• How to efficiently convert String, integer, double, datetime to binary and vica versa?

  - by Ben

  Hi, I'm quite new to C# (I'm using .NET 4.0) so please bear with me. I need to save some object properties (their properties are int, double, String, boolean, datetime) to a file. But I want to encrypt the files using my own encryption, so I can't use FileStream to convert to binary. Also I don't want to use object serialization, because of performance issues. The idea is simple, first I need to somehow convert objects (their properties) to binary (array), then encrypt (some sort of xor) the array and append it to the end of the file. When reading first decrypt the array and then somehow convert the binary array back to object properties (from which I'll generate objects). I know (roughly =) ) how to convert these things by hand and I could code it, but it would be useless (too slow). I think the best way would be just to get properties' representation in memory and save that. But I don't know how to do it using C# (maybe using pointers?). Also I though about using MemoryStream but again I think it would be inefficient. I am thinking about class Converter, but it does not support toByte(datetime) (documentation says it always throws exception). For converting back I think the only options is class Converter. Note: I know the structure of objects and they will not change, also the maximum String length is also known. Thank you for all your ideas and time. EDIT: I will be storing only parts of objects, in some cases also parts of different objects (a couple of properties from one object type and a couple from another), thus I think that serialization is not an option for me.

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• Creating futures using Apple's GCD

  - by jer

  I'm working on a library which implements the actor model on top of Grand Central Dispatch (specifically the C level API libdispatch). Basically a brief overview of my system is as such: Communication happens between actors using messages Multicast communication only (one actor to many actors) Senders and receivers are decoupled from one another using a blackboard where messages are pushed to. Messages are sent in the default queue asynchronously using dispatch_group_async() once a message gets pushed onto the blackboard. I'm trying to implement futures in the language right now, so I've created a new type which holds some information: A group of its own The value being 'returned' However, I have a problem since dispatch_block_t is of type void (^)(void) so it doesn't return anything. So my idea of in my future_new() function of setting up another group which can be used to execute a block returning a result, which I can store in my "value" member in my future_t structure, isn't going to work. The rest of the futures implementation is very clear, except it all depends on being able to get the value into the future back from the actor, acting on the message. When using the library, it would greatly reduce its usefulness if I had to ask users (and myself) to be aware when futures were going to be used by other parts of the system—It just isn't practical. I'm wondering if anyone can think of a way around this?

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• Sorting out POCO, Repository Pattern, Unit of Work, and ORM

  - by CoffeeAddict

  I'm reading a crapload on all these subjects: POCO Repository Pattern Unit of work Using an ORM mapper ok I see the basic definitions of each in books, etc. but I can't visualize this all together. Meaning an example structure (DL, BL, PL). So what, you have your DL objects that contain your CRUD methods, then your BL objects which are "mapped" using an ORM back to your DL objects? What about DTOs...they're your DL objects right? I'm confused. Can anyone really explain all this together or send me example code? I'm just trying to put this together. I am determining whether to go LINQ to SQL or EF 4 (not sure about NHibrernate yet). Just not getting the concepts as in physical layers and code layers here and what each type of object contains (just properties for DTOs, and CRUDs for your core DL classes that match the table fields???). I just need some guidance here. I'm reading Fowler's books and starting to read Evans but just not all there yet.

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• Getting registry information using Python

  - by Willy

  I am trying to pull registry info from many servers and put them all into one txt file. I got the code working fine in a .bat file. I hear that there is a way simpler way to do this in Python. I am intrigued and delighted to hear this. Can anyone help finish my code: My working bat file: echo rfsqlcl01app >> foo.txt reg query "\\rfsqlcl01app\HKEY_LOCAL_MACHINE\SOFTWARE\Network Associates\TVD\Shared Components\On Access Scanner\McShield\Configuration\Default" >> foo.txt echo GLADGSQL01 >> foo.txt reg query "\\GLADGSQL01\HKEY_LOCAL_MACHINE\SOFTWARE\Network Associates\TVD\Shared Components\On Access Scanner\McShield\Configuration\Default" >> foo.txt echo GLADGWEB01 >> foo.txt reg query "\\GLADGWEB01\HKEY_LOCAL_MACHINE\SOFTWARE\Network Associates\TVD\Shared Components\On Access Scanner\McShield\Configuration\Default" >> foo.txt echo PAPERVISION >> foo.txt My python code structure: >>> server_list = open('server_test.txt', 'r') >>> for line in server_list: print r'reg query \\%s\blah\blah\blah' % line.strip() reg query \\foo\blah\blah\blah reg query \\moo\blah\blah\blah reg query \\boo\blah\blah\blah >>> server_list.close()

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• C# - retrieve file path from config file - @ doesn't do it's magic

  - by Bart

  Hi guys, I'm currently working on a web service that retrieves an XML message, archives it and then processes it further. The archive folder is read from the Web.config. This is what the archive method looks like private void Archive(System.Xml.XmlDocument xmlDocument) { try { string directory = System.Configuration.ConfigurationManager.AppSettings.Get("ArchivePath"); ParseMessage(xmlDocument); directory = string.Format(@"{0}\{1}\{2}", @directory, _senderService, DateTime.Now.ToString("MMMyyyy")); System.IO.Directory.CreateDirectory(directory); string Id = _messageID; string senderService = _senderService; xmlDocument.Save(directory + @"\" + DateTime.Now.ToString("yyyyMMdd_") + Id + "_" + System.Guid.NewGuid().ToString().Substring(0, 13) + ".xml"); } The path structure I retrieve is C:\Program Files\Subfolder\Subfolder. In the development, QA, UAT and PRD environments everything works fine. But on another machine I now need to install the web service on (which I cannot debug, unfortunately), the directory string is 'C:Files'. Just to be sure I double checked the .NET version on the different machines (I thought perhaps the usage of @ before a string was version-dependent); all machines use 2.0.50727. Does anyone recognize this problem? Thanks in advance!

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• Querying a 3rd party website's database from my website

  - by Mong134

  The Goal: To retrieve information from a 3rd party database based off of a user's query on my ASP.NET website The Details: I need to be able to search 3rd-party websites for information relating to pharmaceutical drugs. Basically, here's what I've been tasked with: a user starts entering the name of a drug they're using in their experiments, and while they're typing a 3rd party website (e.g., here or here) is queried and suggestions are made based based off of what they've typed. Once they've made a selection, certain properties (molecular weight, chemical structure, etc) are retrieved from the 3rd party database and stored in our database. PharmaGKB.org's search bar is pretty much what I need to implement, but I need to access a 3rd party db. The site that I'm working on is ASP.NET/C#. The Problem: I don't really know where to start with this. There's a downloadable Perl example at the bottom of the page here, but it didn't really help me all that much. I'm at a loss as to how to implement this, or even find information about how to do it. The AJAX toolkit was suggested, but I'm not sure if that will solve the issue. JavaScript is also being considered, but again, I'm not sure if that will be sufficient, either. Perl Example Connection As a mentioned, here is a snippet from the Perl example given on the Pharmgkb.org site: my $call = SOAP::Lite -> readable (1) -> uri('SearchService') -> proxy('http://www.pharmgkb.org/services/SearchService') -> search ($ARGV[0]); However, I'm not sure how to implement this is C#/ASP.NET/JavaScript. There's a question on Stack Overflow about embedding Perl in C#, but it require a C wrapper as well, and I don't think that three languages is necessary or wise to solve this issue.

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• Understanding Wordpress database schema - querying from 3rd party app

  - by deceze

  Is there an easy way to grab the latest posts out of a Wordpress wp_posts table using a simple SQL query? I have a Wordpress 2.9.2 installation as part of, but separate from, a larger system. It has a customized theme to look like the rest of the site but has otherwise nothing to do with it. I want to display the latest handful of headlines of posts made using Wordpress on a site of that other system. Preferably I do not want to mess around with importing any of the Wordpress library files. Looking at the database structure I can't see an easy, straight-forward query to simply get the latest revision of the latest posts. The post_status can either be "post" or "inherit", the post_type "post" or "revision" and the parent "0" or the id of the original post of a revision. I can't figure out how to reliably filter different revisions of the same post, drafts, attachments and pages out of this mess and just get the latest revision of the latest posts. I'm aware that the database schema is subject to change in subsequent versions of Wordpress, so shouldn't be relied upon, but that's a minor concern, since it's such a minor feature that could easily be fixed. If I understood how that database is supposed to work, that is.

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• Moving information between databases

  - by williamjones

  I'm on Postgres, and have two databases on the same machine, and I'd like to move some data from database Source to database Dest. Database Source: Table User has a primary key Table Comments has a primary key Table UserComments is a join table with two foreign keys for User and Comments Dest looks just like Source in structure, but already has information in User and Comments tables that needs to be retained. I'm thinking I'll probably have to do this in a few steps. Step 1, I would dump Source using the Postgres Copy command. Step 2, In Dest I would add a temporary second_key column to both User and Comments, and a new SecondUserComments join table. Step 3, I would import the dumped file into Dest using Copy again, with the keys input into the second_key columns. Step 4, I would add rows to UserComments in Dest based on the contents of SecondUserComments, only using the real primary keys this time. Could this be done with a SQL command or would I need a script? Step 5, delete the SecondUserComments table and remove the second_key columns. Does this sound like the best way to do this, or is there a better way I'm overlooking?

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• PHP + MYSQLI: Variable parameter/result binding with prepared statements.

  - by Brian Warshaw

  In a project that I'm about to wrap up, I've written and implemented an object-relational mapping solution for PHP. Before the doubters and dreamers cry out "how on earth?", relax -- I haven't found a way to make late static binding work -- I'm just working around it in the best way that I possibly can. Anyway, I'm not currently using prepared statements for querying, because I couldn't come up with a way to pass a variable number of arguments to the bind_params() or bind_result() methods. Why do I need to support a variable number of arguments, you ask? Because the superclass of my models (think of my solution as a hacked-up PHP ActiveRecord wannabe) is where the querying is defined, and so the find() method, for example, doesn't know how many parameters it would need to bind. Now, I've already thought of building an argument list and passing a string to eval(), but I don't like that solution very much -- I'd rather just implement my own security checks and pass on statements. Does anyone have any suggestions (or success stories) about how to get this done? If you can help me solve this first problem, perhaps we can tackle binding the result set (something I suspect will be more difficult, or at least more resource-intensive if it involves an initial query to determine table structure).

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• Counting entries in a list of dictionaries: for loop vs. list comprehension with map(itemgetter)

  - by Dennis Williamson

  In a Python program I'm writing I've compared using a for loop and increment variables versus list comprehension with map(itemgetter) and len() when counting entries in dictionaries which are in a list. It takes the same time using a each method. Am I doing something wrong or is there a better approach? Here is a greatly simplified and shortened data structure: list = [ {'key1': True, 'dontcare': False, 'ignoreme': False, 'key2': True, 'filenotfound': 'biscuits and gravy'}, {'key1': False, 'dontcare': False, 'ignoreme': False, 'key2': True, 'filenotfound': 'peaches and cream'}, {'key1': True, 'dontcare': False, 'ignoreme': False, 'key2': False, 'filenotfound': 'Abbott and Costello'}, {'key1': False, 'dontcare': False, 'ignoreme': True, 'key2': False, 'filenotfound': 'over and under'}, {'key1': True, 'dontcare': True, 'ignoreme': False, 'key2': True, 'filenotfound': 'Scotch and... well... neat, thanks'} ] Here is the for loop version: #!/usr/bin/env python # Python 2.6 # count the entries where key1 is True # keep a separate count for the subset that also have key2 True key1 = key2 = 0 for dictionary in list: if dictionary["key1"]: key1 += 1 if dictionary["key2"]: key2 += 1 print "Counts: key1: " + str(key1) + ", subset key2: " + str(key2) Output for the data above: Counts: key1: 3, subset key2: 2 Here is the other, perhaps more Pythonic, version: #!/usr/bin/env python # Python 2.6 # count the entries where key1 is True # keep a separate count for the subset that also have key2 True from operator import itemgetter KEY1 = 0 KEY2 = 1 getentries = itemgetter("key1", "key2") entries = map(getentries, list) key1 = len([x for x in entries if x[KEY1]]) key2 = len([x for x in entries if x[KEY1] and x[KEY2]]) print "Counts: key1: " + str(key1) + ", subset key2: " + str(key2) Output for the data above (same as before): Counts: key1: 3, subset key2: 2 I'm a tiny bit surprised these take the same amount of time. I wonder if there's something faster. I'm sure I'm overlooking something simple. One alternative I've considered is loading the data into a database and doing SQL queries, but the data doesn't need to persist and I'd have to profile the overhead of the data transfer, etc., and a database may not always be available. I have no control over the original form of the data. The code above is not going for style points.

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• How can you trigger the viewWillAppear of a UITableView AFTER its UINavigationController?

  - by Troy Sartain

  I have a situation where I use a tab bar set up but with nav bar controllers on a couple tabs. Those tabs have table views on them. Everything works great, I can pick a tab and get a different table in a nav bar structure. The other tabs are non-nav controllers. Fine. I want to use the same table view controller and even the same detail screen since they are essentially the same format. I have two-dimensional arrays and a couple of vars tracking which tab and which table row so when I get to the detail it's all good. Now to the problem. It all seems to work just fine until I return to a tab that has already been visited. At that point, I do indeed get a viewWillAppear for both the view controller of that specific tab and the table view controller. However, I get the table view one first! It doesn't know which tab was tapped on; the other one does but that's too late to dynamically change the table! Any suggestions? Am I being too greedy about code duplication? I mean I could just make separate controllers for for each table view and then separate detail view controllers but I thought I had a good solution.

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• Are monads Writer m and Either e categorically dual?

  - by sdcvvc

  I noticed there is a dual relation between Writer m and Either e monads. If m is a monoid, then unit :: () -> m join :: (m,m) -> m can be used to form a monad: return is composition: a -> ((),a) -> (m,a) join is composition: (m,(m,a)) -> ((m,m),a) -> (m,a) The dual of () is Void (empty type), the dual of product is coproduct. Every type e can be given "comonoid" structure: unit :: Void -> e join :: Either e e -> e in the obvious way. Now, return is composition: a -> Either Void a -> Either e a join is composition: Either e (Either e a) -> Either (Either e e) a -> Either e a and this is the Either e monad. The arrows follow exactly the same pattern. Question: Is it possible to write a single generic code that will be able to perform both as Either e and as Writer m depending on the monoid given?

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• How to model a mutually exclusive relationship in sql server

  - by littlechris

  Hi, I have to add functionality to an existing application and I've run into a data situation that I'm not sure how to model. I am being restricted to the creation of new tables and code. If I need to alter the existing structure I think my client may reject the proposal..although if its the only way to get it right this is what I will have to do. I have an Item table that can me link to any number of tables, and these tables may increase over time. The Item can only me linked to one other table, but the record in the other table may have many items linked to it. Examples of the tables/entities being linked to are "Person", "Vehicle", "Building", "Office". These are all separate tables. Example of Items are "Pen", "Stapler", "Cushion", "Tyre", "A4 Paper", "Plastic Bag", "Poster", "Decoration" For instance a "Poster" may be allocated to a "Person" or "Office" or "Building". In the future if they add a "Conference Room" table it may also be added to that. My intital thoughts are: Item { ID, Name } LinkedItem { ItemID, LinkedToTableName, LinkedToID } The LinkedToTableName field will then allow me to identify the correct table to link to in my code. I'm not overly happy with this solution, but I can't quite think of anything else. Please help! :) Thanks!

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