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  • Need help with Java Producer Consumer Problem, NullPointerException

    - by absk
    This is my code: package test; import java.util.logging.Level; import java.util.logging.Logger; class Data{ int ar[]=new int[50]; int ptr; Data() { for(int i=0;i<50;i++) ar[i]=0; ptr=0; } public int produce() { if(this.ptr<50) { this.ar[this.ptr]=1; this.ptr++; return this.ptr; } else return -1; } public int consume() { if(this.ptr>0) { this.ar[this.ptr]=0; this.ptr--; return this.ptr; } else return -1; } } class Prod implements Runnable{ private Main m; Prod(Main mm) { m=mm; } public void run() { int r = m.d.produce(); if (r != -1) { System.out.println("Produced, total elements: " + r); } else { try { wait(); } catch (InterruptedException ex) { Logger.getLogger(Prod.class.getName()).log(Level.SEVERE, null, ex); } } } } class Cons implements Runnable{ private Main m; Cons(Main mm) { m=mm; } public void run() { int r=m.d.consume(); if(r!=-1) System.out.println("Consumed, total elements: " + r); else { try { wait(); } catch (InterruptedException ex) { Logger.getLogger(Prod.class.getName()).log(Level.SEVERE, null, ex); } } notify(); } } public class Main{ Data d; public static void main(String s[]) throws InterruptedException{ Main m = new Main(); Prod p = new Prod(m); Cons c = new Cons(m); new Thread(p).start(); new Thread(c).start(); } } It is giving following errors: Exception in thread "Thread-0" Exception in thread "Thread-1" java.lang.NullPointerException at test.Cons.run(Main.java:84) at java.lang.Thread.run(Thread.java:619) java.lang.NullPointerException at test.Prod.run(Main.java:58) at java.lang.Thread.run(Thread.java:619) I am new to Java. Any help will be appreciated.

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  • Ask the Readers: Backing Your Files Up – Local Storage versus the Cloud

    - by Asian Angel
    Backing up important files is something that all of us should do on a regular basis, but may not have given as much thought to as we should. This week we would like to know if you use local storage, cloud storage, or a combination of both to back your files up. Photo by camknows. For some people local storage media may be the most convenient and/or affordable way to back up their files. Having those files stored on media under your control can also provide a sense of security and peace of mind. But storing your files locally may also have drawbacks if something happens to your storage media. So how do you know whether the benefits outweigh the disadvantages or not? Here are some possible pros and cons that may affect your decision to use local storage to back up your files: Local Storage Pros You are in control of your data Your files are portable and can go with you when needed if using external or flash drives Files are accessible without an internet connection You can easily add more storage capacity as needed (additional drives, etc.) Cons You need to arrange room for your storage media (if you have multiple externals drives, etc.) Possible hardware failure No access to your files if you forget to bring your storage media with you or it is too bulky to bring along Theft and/or loss of home with all contents due to circumstances like fire If you are someone who is always on the go and needs to travel as lightly as possible, cloud storage may be the perfect way for you to back up and access your files. Perhaps your laptop has a hard-drive failure or gets stolen…unhappy events to be sure, but you will still have a copy of your files available. Perhaps a company wants to make sure their records, files, and other information are backed up off site in case of a major hardware or system failure…expensive and/or frustrating to fix if it happens, but once again there is a nice backup ready to go once things are fixed. As with local storage, here are some possible pros and cons that may influence your choice of cloud storage to back up your files: Cloud Storage Pros No need to carry around flash or bulky external drives All of your files are accessible wherever there is an internet connection No need to deal with local storage media (or its’ upkeep) Your files are still safe if your home is broken into or other unfortunate circumstances occur Cons Your files and data are not 100% under your control Possible hardware failure or loss of files on the part of your cloud storage provider (this could include a disgruntled employee wreaking havoc) No access to your files if you do not have an internet connection The cloud storage provider may eventually shutdown due to financial hardship or other unforeseen circumstances The possibility of your files and data being stolen by hackers due to a security breach on the part of your cloud storage provider You may also prefer to try and cover all of the possibilities by using both local and cloud storage to back up your files. If something happens to one, you always have the other to fall back on. Need access to those files at or away from home? As long as you have access to either your storage media or an internet connection, you are good to go. Maybe you are getting ready to choose a backup solution but are not sure which one would work better for you. Here is your chance to ask your fellow HTG readers which one they would recommend. Got a great backup solution already in place? Then be sure to share it with your fellow readers! How-To Geek Polls require Javascript. Please Click Here to View the Poll. Latest Features How-To Geek ETC The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know Winter Sunset by a Mountain Stream Wallpaper Add Sleek Style to Your Desktop with the Aston Martin Theme for Windows 7 Awesome WebGL Demo – Flight of the Navigator from Mozilla Sunrise on the Alien Desert Planet Wallpaper Add Falling Snow to Webpages with the Snowfall Extension for Opera [Browser Fun] Automatically Keep Up With the Latest Releases from Mozilla Labs in Firefox 4.0

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  • Multitenancy in SQL Azure

    - by cibrax
    If you are building a SaaS application in Windows Azure that relies on SQL Azure, it’s probably that you will need to support multiple tenants at database level. This is short overview of the different approaches you can use for support that scenario, A different database per tenant A new database is created and assigned when a tenant is provisioned. Pros Complete isolation between tenants. All the data for a tenant lives in a database only he can access. Cons It’s not cost effective. SQL Azure databases are not cheap, and the minimum size for a database is 1GB.  You might be paying for storage that you don’t really use. A different connection pool is required per database. Updates must be replicated across all the databases You need multiple backup strategies across all the databases Multiple schemas in a database shared by all the tenants A single database is shared among all the tenants, but every tenant is assigned to a different schema and database user. Pros You only pay for a single database. Data is isolated at database level. If the credentials for one tenant is compromised, the rest of the data for the other tenants is not. Cons You need to replicate all the database objects in every schema, so the number of objects can increase indefinitely. Updates must be replicated across all the schemas. The connection pool for the database must maintain a different connection per tenant (or set of credentials) A different user is required per tenant, which is stored at server level. You have to backup that user independently. Centralizing the database access with store procedures in a database shared by all the tenants A single database is shared among all the tenants, but nobody can read the data directly from the tables. All the data operations are performed through store procedures that centralize the access to the tenant data. The store procedures contain some logic to map the database user to an specific tenant. Pros You only pay for a single database. You only have a set of objects to maintain and backup. Cons There is no real isolation. All the data for the different tenants is shared in the same tables. You can not use traditional ORM like EF code first for consuming the data. A different user is required per tenant, which is stored at server level. You have to backup that user independently. SQL Federations A single database is shared among all the tenants, but a different federation is used per tenant. A federation in few words, it’s a mechanism for horizontal scaling in SQL Azure, which basically uses the idea of logical partitions to distribute data based on certain criteria. Pros You only have a single database with multiple federations. You can use filtering in the connections to pick the right federation, so any ORM could be used to consume the data. Cons There is no real isolation at that database level. The isolation is enforced programmatically with federations.

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  • Scheme Depth-first search of a graph function

    - by John Retallack
    This is a homework question,I'm trying to do a Depth-first search function in Scheme,Here's the code I've written so far: (define explore (?(node visited) (let* ([neighbors (force (cdr node))] [next (nextNode visited neighbors)] [is-visited (member? node visited)]) (cond ;if I have no unvisited neighbours print current node and go up one level [(equal? next #f) (begin (display (car node)) (display " "))] ;if current node is not visited and I have unvisited neighbors ;print current node,mark as visited and visit it's neighbors [(and (equal? is-visited #f) (not (equal? next #f))) (begin (display (car node)) (display " ") (explore next (cons node visited)))]) ;go and visit the next neighbor (if (not (equal? (nextNode (cons next visited) neighbors) #f )) (explore (nextNode (cons next visited) neighbors) (cons node visited)))))) 'node' is the current node 'visited' is a list in witch I keep track of the nodes I visited 'nextNode' is a function that returns the first unvisited neighbor if any or #f otherwise 'member?' test's if a node is in the visited list The Graph representation is using adjacent made using references to nodes with letrec so that's why I use force in 'neighbors': Eg: (letrec ([node1 (list "NY" (delay (list node2 node3)))],where node2 and node3 are defined as node1 The problem witch I'm dealing with is that my visited lists looses track of some of the nodes I visited when I come out of recursion,How can I fix this ?

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  • Scheme: what are the benefits of letrec?

    - by Ixmatus
    While reading "The Seasoned Schemer" I've begun to learn about letrec. I understand what it does (can be duplicated with a Y-Combinator) but the book is using it in lieu of recurring on the already defined function operating on arguments that remain static. An example of an old function using the defined function recurring on itself (nothing special): (define (substitute new old lat) (cond ((null? l) '()) ((eq? (car l) old) (cons new (substitute new old (cdr l)))) (else (cons (car l) (substitute new old (cdr l)))))) Now for an example of that same function but using letrec: (define (substitute new old lat) (letrec ((replace (lambda (l) (cond ((null? l) '()) ((eq? (car l) old) (cons new (replace (cdr l)))) (else (cons (car l) (replace (cdr l)))))))) (replace lat))) Aside from being slightly longer and more difficult to read I don't know why they are rewriting functions in the book to use letrec. Is there a speed enhancement when recurring over a static variable this way because you don't keep passing it?? Is this standard practice for functions with arguments that remain static but one argument that is reduced (such as recurring down the elements of a list)? Some input from more experienced Schemers/LISPers would help!

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  • Problem with circular definition in Scheme

    - by user8472
    I am currently working through SICP using Guile as my primary language for the exercises. I have found a strange behavior while implementing the exercises in chapter 3.5. I have reproduced this behavior using Guile 1.4, Guile 1.8.6 and Guile 1.8.7 on a variety of platforms and am certain it is not specific to my setup. This code works fine (and computes e): (define y (integral (delay dy) 1 0.001)) (define dy (stream-map (lambda (x) x) y)) (stream-ref y 1000) The following code should give an identical result: (define (solve f y0 dt) (define y (integral (delay dy) y0 dt)) (define dy (stream-map f y)) y) (solve (lambda (x) x) 1 0.001) But it yields the error message: standard input:7:14: While evaluating arguments to stream-map in expression (stream-map f y): standard input:7:14: Unbound variable: y ABORT: (unbound-variable) So when embedded in a procedure definition, the (define y ...) does not work, whereas outside the procedure in the global environment at the REPL it works fine. What am I doing wrong here? I can post the auxiliary code (i.e., the definitions of integral, stream-map etc.) if necessary, too. With the exception of the system-dependent code for cons-stream, they are all in the book. My own implementation of cons-stream for Guile is as follows: (define-macro (cons-stream a b) `(cons ,a (delay ,b)))

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  • SCOM 2007 versus Zenoss (or other open source)

    - by TheCleaner
    I've taken the liberty to test both SCOM 2007 and Zenoss and found the following: SCOM 2007 Pros: Great MS Windows server monitoring and reporting In-depth configuration and easily integrates into a "MS datacenter" Cons: limited network device monitoring support (without 3rd party plugins) expensive difficult learning curve Zenoss Pros: Open Source (free) decent server monitoring for Windows, great monitoring for Linux decent network device monitoring Cons: not as in-depth as SCOM (for Windows at least) So my question to you folks is this: Given the above, and given that I'm trying to monitor 55 Windows servers, 1 Linux server, 2 ESX servers, and Juniper equipment...which would you recommend?

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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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  • Single python file distribution: module or package?

    - by DanielSank
    Suppose I have a useful python function or class (or whatever) called useful_thing which exists in a single file. There are essentialy two ways to organize the source tree. The first way uses a single module: - setup.py - README.rst - ...etc... - foo.py where useful_thing is defined in foo.py. The second strategy is to make a package: - setup.py - README.rst - ...etc... - foo |-module.py |-__init__.py where useful_thing is defined in module.py. In the package case __init__.py would look like this from foo.module import useful_thing so that in both cases you can do from foo import useful_thing. Question: Which way is preferred, and why? EDIT: Since user gnat says this question is poorly formed, I'll add that the official python packaging tutorial does not seem to comment on which of the methods described above is the preferred one. I am explicitly not giving my personal list of pros and cons because I'm interested in whether there is a community preferred method, not generating a discussion of pros/cons :)

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  • Starting a career in mobile development in next 5 months?

    - by Jungle Hunter
    I will be starting my career shortly and have the opportunity to being my career in mobility. I have an option to be in more traditional fields (the ones that have been around for quite some time now like web development and Java apps development). What are the pros and cons of both? Also, if I do choose mobility, then I might be presented with the option of iOS or Android. Pros and cons of choosing each? Period: Joining in next 5 months. Mobility company profile: Major consulting company.

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  • Is ORM an Anti-Pattern?

    - by derphil
    I had a very stimulating and interessting discussion with a colleague about ORM and it's Pros and Cons. In my opinion, an ORM is useful only in the rarest cases. At least in my experience. But I don't want to list my own arguments at this time. So I ask you, what do you think about ORM? What are the Pros and the Cons? P.S. I've posted this "question" yesterday on Stackoverflow, but some of the user think, that this should better posted here.

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  • Can mass different log-in pages result in SEO duplicate and/or low quality punishments?

    - by Noam
    I have internal pages that rely on an external API which I would like to build upon user request. Two options I thought about: Make lots of 'thin' pages that specifies that if you want content about X, you need to log-in, and then the page will be built. Pros: user understands what he'll get when logging in. Cons: SEO implications of such a solution due to the mass 'low quality' and 'cross-sites duplicate content' Make them all redirect to ONE same generic log-in page. Pros: No duplicate low quality content. Cons: Lots of internal links to the same log-in page. Which would you recommend?

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  • Architecture driven by users, or by actions/content?

    - by hugerth
    I have a question about designing MVC app architecture. Let's say our application has three main categories of views (items of type 1, items of type 2...). And we have three (or more in future) types of users - Admins, let's say Moderators and typical Users. And in the future there might be more of them. Admins have full access to app, Moderators can visit only 2/3 type of items, and Users can visit only basic type of items. Should I divide my controllers/views/whatever like this: Items "A", Items "B", Items "C", then make them 100% finished and at the end add access privileges? Pros: DRY option Cons Conditional expressions in views Or another options: Items "A" / Admin, Items "A" / Moderator / Items "B" Admin ...? Pros: Divided parts of application for specific user (is that pros?) Cons: A lot of repeated code I don't have great experience in planning such things so it would nice if you can give me some tips or links to learn something about it.

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  • when should be choose simple php mail and when smpt with loggin+password?

    - by user43353
    Hi, My Case: web application that need to send 1,000 messages per day to main gmail account. (Only need to send email, not need receive emails - email client) 1. option - use php mail function + sendmail + config php.ini php example: <?php $to = '[email protected]'; $subject = 'the subject'; $message = 'hello'; $headers = 'From: [email protected]' . "\r\n" . 'Reply-To: [email protected]' . "\r\n" . 'X-Mailer: PHP/' . phpversion(); mail($to, $subject, $message, $headers); ?> php.ini config (ubuntu): sendmail_path = /usr/sbin/sendmail -t -i pros:don't need email account, easy to setup cons:? 2. option - use Zend_Mail + transport on smpt+ password auto php example(need include Zend_Mail classes): $config = array('auth' => 'login', 'username' => 'myusername', 'password' => 'password'); $transport = new Zend_Mail_Transport_Smtp('mail.server.com', $config); $mail = new Zend_Mail(); $mail->setBodyText('This is the text of the mail.'); $mail->setFrom('[email protected]', 'Some Sender'); $mail->addTo('[email protected]', 'Some Recipient'); $mail->setSubject('TestSubject'); $mail->send($transport); pros:? cons:? Questions: Can 1 option be filtered by gmail email server as spam? please can you add pros + cons to options above Thanks

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  • Upload large files via a webpage

    - by Hultner
    What way is the best way to let users upload large files from there webbrowser to a server. I'm talking 200MB+ possible up to a few gigatyes. I have been thinking of a few possible solutions to the problem (not tried them yet) and this is basically the things I came up with. Server download speed will not be a problem but the users connection possibly could. Having some sort of applet on the client side written in Java or Flash which sends the file in parts (is this possible with an applet) to a php/other script on the server and a checksum+ some other info about the file. On the server scripts all the parts and the info file is saved in a temporary directory wich has a unique name based on the checksum of the file and the ip of the user. When the last chunk is sent the applet sends a signal to the server saying it's finished and the server put the file together in the right location. If a chunk doesn't match the checksum for that part the server will send a response to the applet telling it to reupload that chunk. I don't know how important the checksum checking is since it's all tcpackages, someone with more insigth migth be able to answer on that. This is probably the worst way, changing the settings on your server to allow huge fileuploads via an inputfiel. Do it like a normal transfer. User an uploadmanager which does pretty much the same thing as applet i mentioned above. Pros of the first is probably that it would most likely be rather secure, you could show progress as well and possibly resume an upload if ip hasn't changed and do a threaded upload of the chunks. Cons of the first is that the user will need flash/java for it to work. Pros of the 2nd is that it will pretty much work for everyone but cons are big, first there's no way resuming an intruppted download and if something is wrong the whole file would have to be reuploaded is a few of cons. For the third one the pros is pretty muc the same as for the first but the cons is that the user would have to download an application to their computer and run and the application will have to be have to be compatible with their computer and OS. Another way may be a combination of two. Lets say an applet for bigger or more files and a simple input which is rather restricted to maybe max 10-20MB for smaller files and comability. There are probably other much smarter ways to tackle this and that's why I'm asking for advice here on SO.

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  • How to generate DELETE statements in PL/SQL, based on the tables FK relations?

    - by The chicken in the kitchen
    Is it possible via script/tool to generate authomatically many delete statements based on the tables fk relations, using Oracle PL/SQL? In example: I have the table: CHICKEN (CHICKEN_CODE NUMBER) and there are 30 tables with fk references to its CHICKEN_CODE that I need to delete; there are also other 150 tables foreign-key-linked to that 30 tables that I need to delete first. Is there some tool/script PL/SQL that I can run in order to generate all the necessary delete statements based on the FK relations for me? (by the way, I know about cascade delete on the relations, but please pay attention: I CAN'T USE IT IN MY PRODUCTION DATABASE, because it's dangerous!) I'm using Oracle DataBase 10G R2. This is the result I've written, but it is not recursive: This is a view I have previously written, but of course it is not recursive! CREATE OR REPLACE FORCE VIEW RUN ( OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, VINCOLO ) AS SELECT OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, '(' || LTRIM ( EXTRACT (XMLAGG (XMLELEMENT ("x", ',' || COLUMN_NAME)), '/x/text()'), ',') || ')' VINCOLO FROM ( SELECT CON1.OWNER OWNER_1, CON1.TABLE_NAME TABLE_NAME_1, CON1.CONSTRAINT_NAME CONSTRAINT_NAME_1, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME FROM DBA_CONSTRAINTS CON, DBA_CONS_COLUMNS COL, DBA_CONSTRAINTS CON1 WHERE CON.OWNER = 'TABLE_OWNER' AND CON.TABLE_NAME = 'TABLE_OWNED' AND ( (CON.CONSTRAINT_TYPE = 'P') OR (CON.CONSTRAINT_TYPE = 'U')) AND COL.TABLE_NAME = CON1.TABLE_NAME AND COL.CONSTRAINT_NAME = CON1.CONSTRAINT_NAME --AND CON1.OWNER = CON.OWNER AND CON1.R_CONSTRAINT_NAME = CON.CONSTRAINT_NAME AND CON1.CONSTRAINT_TYPE = 'R' GROUP BY CON1.OWNER, CON1.TABLE_NAME, CON1.CONSTRAINT_NAME, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME) GROUP BY OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME; ... and it contains the error of using DBA_CONSTRAINTS instead of ALL_CONSTRAINTS... Please pay attention to this: http://stackoverflow.com/questions/485581/generate-delete-statement-from-foreign-key-relationships-in-sql-2008/2677145#2677145 Another user has just written it in SQL SERVER 2008, anyone is able to convert to Oracle 10G PL/SQL? I am not able to... :-( This is the code written by another user in SQL SERVER 2008: DECLARE @COLUMN_NAME AS sysname DECLARE @TABLE_NAME AS sysname DECLARE @IDValue AS int SET @COLUMN_NAME = '<Your COLUMN_NAME here>' SET @TABLE_NAME = '<Your TABLE_NAME here>' SET @IDValue = 123456789 DECLARE @sql AS varchar(max) ; WITH RELATED_COLUMNS AS ( SELECT QUOTENAME(c.TABLE_SCHEMA) + '.' + QUOTENAME(c.TABLE_NAME) AS [OBJECT_NAME] ,c.COLUMN_NAME FROM PBANKDW.INFORMATION_SCHEMA.COLUMNS AS c WITH (NOLOCK) INNER JOIN PBANKDW.INFORMATION_SCHEMA.TABLES AS t WITH (NOLOCK) ON c.TABLE_CATALOG = t.TABLE_CATALOG AND c.TABLE_SCHEMA = t.TABLE_SCHEMA AND c.TABLE_NAME = t.TABLE_NAME AND t.TABLE_TYPE = 'BASE TABLE' INNER JOIN ( SELECT rc.CONSTRAINT_CATALOG ,rc.CONSTRAINT_SCHEMA ,lkc.TABLE_NAME ,lkc.COLUMN_NAME FROM PBANKDW.INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc WITH (NOLOCK) INNER JOIN PBANKDW.INFORMATION_SCHEMA.KEY_COLUMN_USAGE lkc WITH (NOLOCK) ON lkc.CONSTRAINT_CATALOG = rc.CONSTRAINT_CATALOG AND lkc.CONSTRAINT_SCHEMA = rc.CONSTRAINT_SCHEMA AND lkc.CONSTRAINT_NAME = rc.CONSTRAINT_NAME INNER JOIN PBANKDW.INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc WITH (NOLOCK) ON rc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG AND rc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA AND rc.UNIQUE_CONSTRAINT_NAME = tc.CONSTRAINT_NAME INNER JOIN PBANKDW.INFORMATION_SCHEMA.KEY_COLUMN_USAGE rkc WITH (NOLOCK) ON rkc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG AND rkc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA AND rkc.CONSTRAINT_NAME = tc.CONSTRAINT_NAME WHERE rkc.COLUMN_NAME = @COLUMN_NAME AND rkc.TABLE_NAME = @TABLE_NAME ) AS j ON j.CONSTRAINT_CATALOG = c.TABLE_CATALOG AND j.CONSTRAINT_SCHEMA = c.TABLE_SCHEMA AND j.TABLE_NAME = c.TABLE_NAME AND j.COLUMN_NAME = c.COLUMN_NAME ) SELECT @sql = COALESCE(@sql, '') + 'DELETE FROM ' + [OBJECT_NAME] + ' WHERE ' + [COLUMN_NAME] + ' = ' + CONVERT(varchar, @IDValue) + CHAR(13) + CHAR(10) FROM RELATED_COLUMNS PRINT @sql Thank to Charles, this is the latest not working release of the software, I have added a parameter with the OWNER because the referential integrities propagate through about 5 other Oracle users (!!!): CREATE OR REPLACE PROCEDURE delete_cascade ( parent_table VARCHAR2, parent_table_owner VARCHAR2) IS cons_name VARCHAR2 (30); tab_name VARCHAR2 (30); tab_name_owner VARCHAR2 (30); parent_cons VARCHAR2 (30); parent_col VARCHAR2 (30); delete1 VARCHAR (500); delete2 VARCHAR (500); delete_command VARCHAR (4000); CURSOR cons_cursor IS SELECT constraint_name, r_constraint_name, table_name, constraint_type FROM all_constraints WHERE constraint_type = 'R' AND r_constraint_name IN (SELECT constraint_name FROM all_constraints WHERE constraint_type IN ('P', 'U') AND table_name = parent_table AND owner = parent_table_owner) AND delete_rule = 'NO ACTION'; CURSOR tabs_cursor IS SELECT DISTINCT table_name FROM all_cons_columns WHERE constraint_name = cons_name; CURSOR child_cols_cursor IS SELECT column_name, position FROM all_cons_columns WHERE constraint_name = cons_name AND table_name = tab_name; BEGIN FOR cons IN cons_cursor LOOP cons_name := cons.constraint_name; parent_cons := cons.r_constraint_name; SELECT DISTINCT table_name, owner INTO tab_name, tab_name_owner FROM all_cons_columns WHERE constraint_name = cons_name; delete_cascade (tab_name, tab_name_owner); delete_command := ''; delete1 := ''; delete2 := ''; FOR col IN child_cols_cursor LOOP SELECT DISTINCT column_name INTO parent_col FROM all_cons_columns WHERE constraint_name = parent_cons AND position = col.position; IF delete1 IS NULL THEN delete1 := col.column_name; ELSE delete1 := delete1 || ', ' || col.column_name; END IF; IF delete2 IS NULL THEN delete2 := parent_col; ELSE delete2 := delete2 || ', ' || parent_col; END IF; END LOOP; delete_command := 'delete from ' || tab_name_owner || '.' || tab_name || ' where (' || delete1 || ') in (select ' || delete2 || ' from ' || parent_table_owner || '.' || parent_table || ');'; INSERT INTO ris VALUES (SEQUENCE_COMANDI.NEXTVAL, delete_command); COMMIT; END LOOP; END; / In the cursor CONS_CURSOR I have added the condition: AND delete_rule = 'NO ACTION'; in order to avoid deletion in case of referential integrities with DELETE_RULE = 'CASCADE' or DELETE_RULE = 'SET NULL'. Now I have tried to turn from stored procedure to stored function, but the delete statements are not correct: CREATE OR REPLACE FUNCTION deletecascade ( parent_table VARCHAR2, parent_table_owner VARCHAR2) RETURN VARCHAR2 IS cons_name VARCHAR2 (30); tab_name VARCHAR2 (30); tab_name_owner VARCHAR2 (30); parent_cons VARCHAR2 (30); parent_col VARCHAR2 (30); delete1 VARCHAR (500); delete2 VARCHAR (500); delete_command VARCHAR (4000); AT_LEAST_ONE_ITERATION NUMBER DEFAULT 0; CURSOR cons_cursor IS SELECT constraint_name, r_constraint_name, table_name, constraint_type FROM all_constraints WHERE constraint_type = 'R' AND r_constraint_name IN (SELECT constraint_name FROM all_constraints WHERE constraint_type IN ('P', 'U') AND table_name = parent_table AND owner = parent_table_owner) AND delete_rule = 'NO ACTION'; CURSOR tabs_cursor IS SELECT DISTINCT table_name FROM all_cons_columns WHERE constraint_name = cons_name; CURSOR child_cols_cursor IS SELECT column_name, position FROM all_cons_columns WHERE constraint_name = cons_name AND table_name = tab_name; BEGIN FOR cons IN cons_cursor LOOP AT_LEAST_ONE_ITERATION := 1; cons_name := cons.constraint_name; parent_cons := cons.r_constraint_name; SELECT DISTINCT table_name, owner INTO tab_name, tab_name_owner FROM all_cons_columns WHERE constraint_name = cons_name; delete1 := ''; delete2 := ''; FOR col IN child_cols_cursor LOOP SELECT DISTINCT column_name INTO parent_col FROM all_cons_columns WHERE constraint_name = parent_cons AND position = col.position; IF delete1 IS NULL THEN delete1 := col.column_name; ELSE delete1 := delete1 || ', ' || col.column_name; END IF; IF delete2 IS NULL THEN delete2 := parent_col; ELSE delete2 := delete2 || ', ' || parent_col; END IF; END LOOP; delete_command := 'delete from ' || tab_name_owner || '.' || tab_name || ' where (' || delete1 || ') in (select ' || delete2 || ' from ' || parent_table_owner || '.' || parent_table || ');' || deletecascade (tab_name, tab_name_owner); INSERT INTO ris VALUES (SEQUENCE_COMANDI.NEXTVAL, delete_command); COMMIT; END LOOP; IF AT_LEAST_ONE_ITERATION = 1 THEN RETURN ' where COD_CHICKEN = V_CHICKEN AND COD_NATION = V_NATION;'; ELSE RETURN NULL; END IF; END; / Please assume that V_CHICKEN and V_NATION are the criteria to select the CHICKEN to delete from the root table: the condition is: "where COD_CHICKEN = V_CHICKEN AND COD_NATION = V_NATION" on the root table.

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  • When should I use MySQL compressed protocol?

    - by ento
    I've learned that MySQL can compress communication between servers and clients. Compression is used if both client and server support zlib compression, and the client requests compression. (from MySQL Forge Wiki) The most obvious pros and cons are pros: Reduced payload size cons: Increased computation time So, is compressed protocol something I should enable whenever I can afford servers with adequate specs? Are there other factors I should consider?

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  • dirname(__FILE__) VS setting global variable to directories

    - by SAFAD
    what are the pros and cons of using this : $globals['server_url'] = dirname(__FILE__); $globals['mainfiles'] = dirname(__FILE__).'/main'; and the pros and cons of using this : $globals['server_url'] = '/srv/www/htdocs/somwhere/'; $globals['mainfiles'] = '/srv/www/htdocs/somwhere/main'; And what do you suggest. by the way: these are set in config.php file which is called by other files as well, to stop directory conflicts when including files we use it like this : require_once($globals['server_url'].'/test.php');

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  • SQL Server 2008 : Standard or SQL Express

    - by dr
    Which is a better choice on a development box if you primarily develop Asp.Net applications and SSRS reports. I have never had to use the Express editions, so I don't really know the pros or cons. The cons I have listed for Standard+ editions are: toll it takes on system resources pain to attach database for projects pain to detach unused databases $$$ Pros: You have everything you need Management Studio features Easy move to production

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  • Why or why not use a DataSource to fill ASP controls?

    - by Brad8118
    So we have a GridView asp control and one of my coworkers doesn't like to use an DataSource to fill the GridView. I wasn't sure if/what the pros and cons are of using one. I don't mind using going through the wizard to set the type, and the select/update methods. Besides using the wizard are there pros and cons?

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  • Contracting as a Software Developer in the UK

    - by Frez
    Normal 0 false false false EN-GB X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} Having had some 15 years’ experience of working as a software contractor, I am often asked by developers who work as permanent employees (permies) about the pros and cons of working as a software consultant through my own limited company and whether the move would be a good one for them. Whilst it is possible to contract using other financial vehicles such as umbrella companies, this article will only consider limited companies as that is what I have experience of using. Contracting or consultancy requires a different mind-set from being a permanent member of staff, and not all developers are capable of this shift in attitude. Whilst you can look forward to an increase in the money you take home, there are real risks and expenses you would not normally be exposed to as a permie. So let us have a look at the pros and cons: Pros: More money There is no doubt that whilst you are working on contracts you will earn significantly more than you would as a permanent employee. Furthermore, working through a limited company is more tax efficient. Less politics You really have no need to involve yourself in office politics. When the end of the day comes you can go home and not think or worry about the power struggles within the company you are contracted to. Your career progression is not tied to the company. Expenses from gross income All your expenses of trading as a business will come out of your company’s gross income, i.e. before tax. This covers travelling expenses provided you have not been at the same client/location for more than two years, internet subscriptions, professional subscriptions, software, hardware, accountancy services and so on. Cons: Work is more transient Contracts typically range from a couple of weeks to a year, although will most likely start at 3 months. However, most contracts are extended either because the project you have been brought in to help with takes longer to deliver than expected, the client decides they can use you on other aspects of the project, or the client decides they would like to use you on other projects. The temporary nature of the work means that you will have down-time between contracts while you secure new opportunities during which time your company will have no income. You may need to attend several interviews before securing a new contract. Accountancy expenses Your company is a separate entity and there are accountancy requirements which, unless you like paperwork, means your company will need to appoint an accountant to prepare your company’s accounts. It may also be worth purchasing some accountancy software, so talk to your accountant about this as they may prefer you to use a particular software package so they can integrate it with their systems. VAT You will need to register your company for VAT. This is tax neutral for you as the VAT you charge your clients you will pass onto the government less any VAT you are reclaiming from expenses, but it is additional paperwork to undertake each quarter. It is worth checking out the Fixed Rate VAT Scheme that is available, particularly after the initial expenses of setting up your company are over. No training Clients take you on based on your skills, not to train you when they will lose that investment at the end of the contract, so understand that it is unlikely you will receive any training funded by a client. However, learning new skills during a contract is possible and you may choose to accept a contract on a lower rate if this is guaranteed as it will help secure future contracts. No financial extras You will have no free pension, life, accident, sickness or medical insurance unless you choose to purchase them yourself. A financial advisor can give you all the necessary advice in this area, and it is worth taking seriously. A year after I started as a consultant I contracted a serious illness, this kept me off work for over two months, my client was very understanding and it could have been much worse, so it is worth considering what your options might be in the case of illness, death and retirement. Agencies Whilst it is possible to work directly for end clients there are pros and cons of working through an agency.  The main advantage is cash flow, you invoice the agency and they typically pay you within a week, whereas working directly for a client could have you waiting up to three months to be paid. The downside of working for agencies, especially in the current difficult times, is that they may go out of business and you then have difficulty getting the money you are owed. Tax investigation It is possible that the Inland Revenue may decide to investigate your company for compliance with tax law. Insurance is available to cover you for this. My personal recommendation would be to join the PCG as this insurance is included as a benefit of membership, Professional Indemnity Some agencies require that you are covered by professional indemnity insurance; this is a cost you would not incur as a permie. Travel Unless you live in an area that has an abundance of opportunities, such as central London, it is likely that you will be travelling further, longer and with more expense than if you were permanently employed at a local company. This not only affects you monetarily, but also your quality of life and the ability to keep fit and healthy. Obtaining finance If you want to secure a mortgage on a property it can be more difficult or expensive, especially if you do not have three years of audited accounts to show a mortgage lender.   Caveat This post is my personal opinion and should not be used as a definitive guide or recommendation to contracting and whether it is suitable for you as an individual, i.e. I accept no responsibility if you decide to take up contracting based on this post and you fare badly for whatever reason.

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  • What's up with LDoms: Part 5 - A few Words about Consoles

    - by Stefan Hinker
    Back again to look at a detail of LDom configuration that is often forgotten - the virtual console server. Remember, LDoms are SPARC systems.  As such, each guest will have it's own OBP running.  And to connect to that OBP, the administrator will need a console connection.  Since it's OBP, and not some x86 BIOS, this console will be very serial in nature ;-)  It's really very much like in the good old days, where we had a terminal concentrator where all those serial cables ended up in.  Just like with other components in LDoms, the virtualized solution looks very similar. Every LDom guest requires exactly one console connection.  Envision this similar to the RS-232 port on older SPARC systems.  The LDom framework provides one or more console services that provide access to these connections.  This would be the virtual equivalent of a network terminal server (NTS), where all those serial cables are plugged in.  In the physical world, we'd have a list somewhere, that would tell us which TCP-Port of the NTS was connected to which server.  "ldm list" does just that: root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- UART 16 7680M 0.4% 27d 8h 22m jupiter bound ------ 5002 20 8G mars active -n---- 5000 2 8G 0.5% 55d 14h 10m venus active -n---- 5001 2 8G 0.5% 56d 40m pluto inactive ------ 4 4G The column marked "CONS" tells us, where to reach the console of each domain. In the case of the primary domain, this is actually a (more) physical connection - it's the console connection of the physical system, which is either reachable via the ILOM of that system, or directly via the serial console port on the chassis. All the other guests are reachable through the console service which we created during the inital setup of the system.  Note that pluto does not have a port assigned.  This is because pluto is not yet bound.  (Binding can be viewed very much as the assembly of computer parts - CPU, Memory, disks, network adapters and a serial console cable are all put together when binding the domain.)  Unless we set the port number explicitly, LDoms Manager will do this on a first come, first serve basis.  For just a few domains, this is fine.  For larger deployments, it might be a good idea to assign these port numbers manually using the "ldm set-vcons" command.  However, there is even better magic associated with virtual consoles. You can group several domains into one console group, reachable through one TCP port of the console service.  This can be useful when several groups of administrators are to be given access to different domains, or for other grouping reasons.  Here's an example: root@sun # ldm set-vcons group=planets service=console jupiter root@sun # ldm set-vcons group=planets service=console pluto root@sun # ldm bind jupiter root@sun # ldm bind pluto root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- UART 16 7680M 6.1% 27d 8h 24m jupiter bound ------ 5002 200 8G mars active -n---- 5000 2 8G 0.6% 55d 14h 12m pluto bound ------ 5002 4 4G venus active -n---- 5001 2 8G 0.5% 56d 42m root@sun # telnet localhost 5002 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. sun-vnts-planets: h, l, c{id}, n{name}, q:l DOMAIN ID DOMAIN NAME DOMAIN STATE 2 jupiter online 3 pluto online sun-vnts-planets: h, l, c{id}, n{name}, q:npluto Connecting to console "pluto" in group "planets" .... Press ~? for control options .. What I did here was add the two domains pluto and jupiter to a new console group called "planets" on the service "console" running in the primary domain.  Simply using a group name will create such a group, if it doesn't already exist.  By default, each domain has its own group, using the domain name as the group name.  The group will be available on port 5002, chosen by LDoms Manager because I didn't specify it.  If I connect to that console group, I will now first be prompted to choose the domain I want to connect to from a little menu. Finally, here's an example how to assign port numbers explicitly: root@sun # ldm set-vcons port=5044 group=pluto service=console pluto root@sun # ldm bind pluto root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- UART 16 7680M 3.8% 27d 8h 54m jupiter active -t---- 5002 200 8G 0.5% 30m mars active -n---- 5000 2 8G 0.6% 55d 14h 43m pluto bound ------ 5044 4 4G venus active -n---- 5001 2 8G 0.4% 56d 1h 13m With this, pluto would always be reachable on port 5044 in its own exclusive console group, no matter in which order other domains are bound. Now, you might be wondering why we always have to mention the console service name, "console" in all the examples here.  The simple answer is because there could be more than one such console service.  For all "normal" use, a single console service is absolutely sufficient.  But the system is flexible enough to allow more than that single one, should you need them.  In fact, you could even configure such a console service on a domain other than the primary (or control domain), which would make that domain a real console server.  I actually have a customer who does just that - they want to separate console access from the control domain functionality.  But this is definately a rather sophisticated setup. Something I don't want to go into in this post is access control.  vntsd, which is the daemon providing all these console services, is fully RBAC-aware, and you can configure authorizations for individual users to connect to console groups or individual domain's consoles.  If you can't wait until I get around to security, check out the man page of vntsd. Further reading: The Admin Guide is rather reserved on this subject.  I do recommend to check out the Reference Manual. The manpage for vntsd will discuss all the control sequences as well as the grouping and authorizations mentioned here.

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  • Question on the implementation of my Entity System

    - by miguel.martin
    I am currently creating an Entity System, in C++, it is almost completed (I have all the code there, I just have to add a few things and test it). The only thing is, I can't figure out how to implement some features. This Entity System is based off a bit from the Artemis framework, however it is different. I'm not sure if I'll be able to type this out the way my head processing it. I'm going to basically ask whether I should do something over something else. Okay, now I'll give a little detail on my Entity System itself. Here are the basic classes that my Entity System uses to actually work: Entity - An Id (and some methods to add/remove/get/etc Components) Component - An empty abstract class ComponentManager - Manages ALL components for ALL entities within a Scene EntitySystem - Processes entities with specific components Aspect - The class that is used to help determine what Components an Entity must contain so a specific EntitySystem can process it EntitySystemManager - Manages all EntitySystems within a Scene EntityManager - Manages entities (i.e. holds all Entities, used to determine whether an Entity has been changed, enables/disables them, etc.) EntityFactory - Creates (and destroys) entities and assigns an ID to them Scene - Contains an EntityManager, EntityFactory, EntitySystemManager and ComponentManager. Has functions to update and initialise the scene. Now in order for an EntitySystem to efficiently know when to check if an Entity is valid for processing (so I can add it to a specific EntitySystem), it must recieve a message from the EntityManager (after a call of activate(Entity& e)). Similarly the EntityManager must know when an Entity is destroyed from the EntityFactory in the Scene, and also the ComponentManager must know when an Entity is created AND destroyed. I do have a Listener/Observer pattern implemented at the moment, but with this pattern I may remove a Listener (which is this case is dependent on the method being called). I mainly have this implemented for specific things related to a game, i.e. Teams, Tagging of entities, etc. So... I was thinking maybe I should call a private method (using friend classes) to send out when an Entity has been activated, deleted, etc. i.e. taken from my EntityFactory void EntityFactory::killEntity(Entity& e) { // if the entity doesn't exsist in the entity manager within the scene if(!getScene()->getEntityManager().doesExsist(e)) { return; // go back to the caller! (should throw an exception or something..) } // tell the ComponentManager and the EntityManager that we killed an Entity getScene()->getComponentManager().doOnEntityWillDie(e); getScene()->getEntityManager().doOnEntityWillDie(e); // notify the listners for(Mouth::iterator i = getMouth().begin(); i != getMouth().end(); ++i) { (*i)->onEntityWillDie(*this, e); } _idPool.addId(e.getId()); // add the ID to the pool delete &e; // delete the entity } As you can see on the lines where I am telling the ComponentManager and the EntityManager that an Entity will die, I am calling a method to make sure it handles it appropriately. Now I realise I could do this without calling it explicitly, with the help of that for loop notifying all listener objects connected to the EntityFactory's Mouth (an object used to tell listeners that there's an event), however is this a good idea (good design, or what)? I've gone over the PROS and CONS, I just can't decide what I want to do. Calling Explicitly: PROS Faster? Since these functions are explicitly called, they can't be "removed" CONS Not flexible Bad design? (friend functions) Calling through Listener objects (i.e. ComponentManager/EntityManager inherits from a EntityFactoryListener) PROS More Flexible? Better Design? CONS Slower? (virtual functions) Listeners can be removed, i.e. may be removed and not get called again during the program, which could cause in a crash. P.S. If you wish to view my current source code, I am hosting it on BitBucket.

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  • Is this over-abstraction? (And is there a name for it?)

    - by mwhite
    I work on a large Django application that uses CouchDB as a database and couchdbkit for mapping CouchDB documents to objects in Python, similar to Django's default ORM. It has dozens of model classes and a hundred or two CouchDB views. The application allows users to register a "domain", which gives them a unique URL containing the domain name that gives them access to a project whose data has no overlap with the data of other domains. Each document that is part of a domain has its domain property set to that domain's name. As far as relationships between the documents go, all domains are effectively mutually exclusive subsets of the data, except for a few edge cases (some users can be members of more than one domain, and there are some administrative reports that include all domains, etc.). The code is full of explicit references to the domain name, and I'm wondering if it would be worth the added complexity to abstract this out. I'd also like to know if there's a name for the sort of bound property approach I'm taking here. Basically, I have something like this in mind: Before in models.py class User(Document): domain = StringProperty() class Group(Document): domain = StringProperty() name = StringProperty() user_ids = StringListProperty() # method that returns related document set def users(self): return [User.get(id) for id in self.user_ids] # method that queries a couch view optimized for a specific lookup @classmethod def by_name(cls, domain, name): # the view method is provided by couchdbkit and handles # wrapping json CouchDB results as Python objects, and # can take various parameters modifying behavior return cls.view('groups/by_name', key=[domain, name]) # method that creates a related document def get_new_user(self): user = User(domain=self.domain) user.save() self.user_ids.append(user._id) return user in views.py: from models import User, Group # there are tons of views like this, (request, domain, ...) def create_new_user_in_group(request, domain, group_name): group = Group.by_name(domain, group_name)[0] user = User(domain=domain) user.save() group.user_ids.append(user._id) group.save() in group/by_name/map.js: function (doc) { if (doc.doc_type == "Group") { emit([doc.domain, doc.name], null); } } After models.py class DomainDocument(Document): domain = StringProperty() @classmethod def domain_view(cls, *args, **kwargs): kwargs['key'] = [cls.domain.default] + kwargs['key'] return super(DomainDocument, cls).view(*args, **kwargs) @classmethod def get(cls, *args, **kwargs, validate_domain=True): ret = super(DomainDocument, cls).get(*args, **kwargs) if validate_domain and ret.domain != cls.domain.default: raise Exception() return ret def models(self): # a mapping of all models in the application. accessing one returns the equivalent of class BoundUser(User): domain = StringProperty(default=self.domain) class User(DomainDocument): pass class Group(DomainDocument): name = StringProperty() user_ids = StringListProperty() def users(self): return [self.models.User.get(id) for id in self.user_ids] @classmethod def by_name(cls, name): return cls.domain_view('groups/by_name', key=[name]) def get_new_user(self): user = self.models.User() user.save() views.py @domain_view # decorator that sets request.models to the same sort of object that is returned by DomainDocument.models and removes the domain argument from the URL router def create_new_user_in_group(request, group_name): group = request.models.Group.by_name(group_name) user = request.models.User() user.save() group.user_ids.append(user._id) group.save() (Might be better to leave the abstraction leaky here in order to avoid having to deal with a couchapp-style //! include of a wrapper for emit that prepends doc.domain to the key or some other similar solution.) function (doc) { if (doc.doc_type == "Group") { emit([doc.name], null); } } Pros and Cons So what are the pros and cons of this? Pros: DRYer prevents you from creating related documents but forgetting to set the domain. prevents you from accidentally writing a django view - couch view execution path that leads to a security breach doesn't prevent you from accessing underlying self.domain and normal Document.view() method potentially gets rid of the need for a lot of sanity checks verifying whether two documents whose domains we expect to be equal are. Cons: adds some complexity hides what's really happening requires no model modules to have classes with the same name, or you would need to add sub-attributes to self.models for modules. However, requiring project-wide unique class names for models should actually be fine because they correspond to the doc_type property couchdbkit uses to decide which class to instantiate them as, which should be unique. removes explicit dependency documentation (from group.models import Group)

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  • A layout for maven project with a patched dependency

    - by zamza
    Suppose, I have an opensource project that depends on some library, that must be patched in order to fix some issues. How do I do that? My ideas are: Have that library sources set up as a module, keep them in my vcs. Pros: simple. Cons: some third party sources in my repo, might slow down build process, hard to find a patched place (though can be fixed in README) Have a module, like in 1, but keep patched source files only, compile them with orignal library jar in classpath and somehow replace *.class files in library jar on build. Pros: builds faster, easy to find patched places. Cons: hard to configure, that jar hackery is non-obvious (library jar in repository and in my project assembly would be different) Keep patched *.class files in main/resources, and replace on packaging like in 2). Pros: almost none. Cons: binaries in vcs, hard to recompile a patched class as patch compilation is not automated. One nice solution is to create a distinct project with patched library sources, and deploy it on local/enterprise repository with -patched qualifier. But that would not fit for an opensourced project that is meant to be easily buildable by anyone who checks out its sources. Or should I just say "and also, before you build my project, please check out that stuff and run mvn install".

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