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  • Scene Graph as Object Container?

    - by Bunkai.Satori
    Scene graph contains game nodes representing game objects. At a first glance, it might seem practical to use Scene Graph as physical container for in game objects, instead of std::vector< for example. My question is, is it practical to use Scene Graph to contain the game objects, or should it be used only to define scene objects/nodes linkages, while keepig the objects stored in separate container, such as std::vector<?

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  • DNRTV: Developing for SharePoint &ndash; Part 2

    - by Sahil Malik
    Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). Carl and I got together a couple of weeks ago and chatted about the various interesting facilities in SharePoint 2010 – especially around some real practical challenges that we faced with SharePoint 2007. We talked about a number of indepth practical stuff, such as scalability and performance in SP2010. The latest episode is now online for your viewing pleasure. Comment on the article ....

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  • Is it OK to write a programming language in Jython? [closed]

    - by Christopher
    I've been looking at the tools for writing a programming language and I had a bizarre idea. What If I wrote a full blown programming language in Jython? Is that a practical solution? Will distribution and bundling be a problem? Can that make or break the language's success? In other words, I'm asking if writing a programing language written in Jython is a practical solution for production enviroments?

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  • SQL SERVER – Quiz and Video – Introduction to SQL Server Security

    - by pinaldave
    This blog post is inspired from Beginning SQL Joes 2 Pros: The SQL Hands-On Guide for Beginners – SQL Exam Prep Series 70-433 – Volume 1. [Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to SQL Server Security – A Primer. In the article we discussed various basics terminology of the security. The article further covers following important concepts of security. Granting Permissions Denying Permissions Revoking Permissions Above three are the most important concepts related to security and SQL Server.  There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced  concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1) If you granted Phil control to the server, but denied his ability to create databases, what would his effective permissions be? Phil can do everything. Phil can do nothing. Phil can do everything except create databases. 2) If you granted Phil control to the server and revoked his ability to create databases, what would his effective permissions be? Phil can do everything. Phil can do nothing. Phil can do everything except create databases. 3) You have a login named James who has Control Server permission. You want to elimintate his ability to create databases without affecting any other permissions. What SQL statement would you use? ALTER LOGIN James DISABLE DROP LOGIN James DENY CREATE DATABASE To James REVOKE CREATE DATABASE To James GRANT CREATE DATABASE To James Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 3 2) 1 3) 3 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Quiz and Video – Introduction to Basics of a Query Hint

    - by pinaldave
    This blog post is inspired from SQL Architecture Basics Joes 2 Pros: Core Architecture concepts – SQL Exam Prep Series 70-433 – Volume 3. [Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to Basics of a Query Hint – A Primer. In the article we discussed various basics terminology of the query hints. The article further covers following important concepts of query hints. Expecting Seek and getting a Scan Creating an index for improved optimization Implementing the query hint Above three are the most important concepts related to query hint and SQL Server.  There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced  concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1) You have the following query: DECLARE @UlaChoice TinyInt SET @Type = 1 SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice You have a nonclustered index named IX_Legal_Ula on the UlaChoice field. The Primary key is on the ID field and called PK_Legal_ID 99% of the time the value of the @UlaChoice is set to ‘YP101′. What query will achieve the best optimization for this query? SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice WITH(INDEX(X_Legal_Ula)) SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice WITH(INDEX(PK_Legal_ID)) SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice OPTION (Optimize FOR(@UlaChoice = ‘YP101′)) 2) You have the following query: SELECT * FROM CurrentProducts WHERE ShortName = ‘Yoga Trip’ You have a nonclustered index on the ShortName field and the query runs an efficient index seek. You change your query to use a variable for ShortName and now you are using a slow index scan. What query hint can you use to get the same execution time as before? WITH LOCK FAST OPTIMIZE FOR MAXDOP READONLY Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 3 2) 4 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Quiz and Video – Introduction to SQL Error Actions

    - by pinaldave
    This blog post is inspired from SQL Programming Joes 2 Pros: Programming and Development for Microsoft SQL Server 2008 – SQL Exam Prep Series 70-433 – Volume 4. [Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to SQL Error Actions – A Primer. In the article we discussed various basics terminology of the error handling. The article further covers following important concepts of error handling. Introduction to SQL Error Actions Statement Termination Scope Abortion Batch Termination Above three are the most important concepts related to error handling and SQL Server.  There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1.) Which SQL Server error action happens for errors with a severity of 11-16 when you set the XACT_ABORT setting to ON? You will get Statement Termination. You will get Scope Abortion. You will get Batch Abortion. You will get Connection Termination. SQL Server will pick the error action. 2.) Which SQL Server error action happens for errors with a severity of 11-16 when you set the XACT_ABORT setting to OFF? You will get Statement Termination You will get Scope Abortion You will get Batch Abortion You will get Connection Termination SQL Server will pick the error action Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 3 2) 5 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Quiz and Video – Introduction to Discovering XML Data Type Methods

    - by pinaldave
    This blog post is inspired from SQL Interoperability Joes 2 Pros: A Guide to Integrating SQL Server with XML, C#, and PowerShell – SQL Exam Prep Series 70-433 – Volume 5. [Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to Discovering XML Data Type Methods – A Primer. In the article we discussed various basics terminology of the XML. The article further covers following important concepts of XML. What are XML Data Type Methods The query() Method The value() Method The exist() Method The modify() Method Above five are the most important concepts related to XML and SQL Server. There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced  concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1.) Which method returns an XML fragment from the source XML? query( ) value( ) exist( ) modify( ) All of them Only query( ) and value( ) 2.) Which XML data type method returns a “1” if found and “0” if the specified XPath is not found in the source XML? query( ) value( ) exist( ) modify( ) All of them Only query( ) and value( ) 3.) Which XML data type method allows you to pick the data type of the value that is returned from the source XML? query( ) value( ) exist( ) modify( ) All of them Only query( ) and value( ) 4.) Which method will not work with a SQL SELECT statement? query( ) value( ) exist( ) modify( ) All of them Only query( ) and value( ) Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 1 2) 3 3) 2 4) 4 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • php if clause inside foreach not retrieving data correctly

    - by Mike
    Here's my issue: In my controller, I want to grab user input from a form. I then parse the input, and compare it to database values to ensure I'm grabbing the correct input. I simply want to match the user's answers to the question, grab the user ID, the question ID, and then determine if the answer applies to a multiple choice or checkbox question, or something else. I take those values and insert them into the answer table. Ignore the waiver stuff. I'll test that once I get the answers input correctly. // add answers and waiver consent records try { $answerArray = array(); $waiverArray = array(); // retrieve answers, waiver consents, and the question ID's from form object foreach ($formData as $key => $value) { $parts = explode("_", $key); if ($parts[0] == 'question') { array_push($answerArray, $value); } if ($parts[0] == 'waiverTitle') { array_push($waiverArray, $value); } } $questions = new Model_DbTable_Questions(); $questionResults = $questions->getQuestionResults($session->idEvent); foreach ( $questionResults as $qr ) { if ($qr ['questionType'] == 'multipleChoice' || $qr ['questionType'] == 'checkBox') { foreach ( $answerArray as $aa ) { $answerData = $answers->addAnswer ( $lastUserID, $qr ['idQuestion'], null, $aa ); echo count ( $answerData ) . ', ' . $qr ['questionType'] . ', ' . $aa . '<br />'; } } else { foreach ( $answerArray as $aa ) { $answerData = $answers->addAnswer ( $lastUserID, $qr ['idQuestion'], $aa, null ); echo count ( $answerData ) . ', ' . $qr ['questionType'] . ', ' . $aa . '<br />'; } } } } catch (Zend_Db_Statement_Exception $e) { $e->getMessage(); throw $e; } From my test data, I expect to get 2 records that match the multiple choice and checkbox criteria, and 1 record for text in the ELSE clause like this: 3, checkbox, 1 3, multipleChoice, 1 3, text, question_2 What I get is a 3x3 Cartesian product, 3 question elements each with the 3 possible answers like this output from the echo statements: 4, checkBox, 1 4, checkBox, 1 4, checkBox, question_2 4, multipleChoice, 1 4, multipleChoice, 1 4, multipleChoice, question_2 4, text, 1 4, text, 1 4, text, question_2 I've tried placing the IF clause inside the inner foreach, but I get the same results. I've been staring at this problem for way too long and cannot see what I'm doing wrong. Your kind assistance would be greatly appreciated. Please let me know if my request requires more clarification.

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  • how to get the result query one by one in jsp and mysql

    - by user261002
    I am trying to implement as Online Mock exam in JSP, but I have a problem to get the questions one by one, it get connceted for the first time, and show me the first question and answers, but when I click on "next" again, it still show me the first question, I think by clicking on "next" it start querying again. please help me. this is my bean : database.SQLSelectStatement sqlselect; database.SQLSelectStatement sqlselect2; static ResultSet questions; static ResultSetMetaData rsm; static ResultSet answers; public void setConnection() throws SQLException { if (database.DatabaseManager.getInstance().connectionOK()) { sqlselect = new database.SQLSelectStatement("question", "question", "0"); sqlselect2 = new database.SQLSelectStatement("answers", "question_id", "0"); questions = sqlselect.executeWithNoCondition(); } } public int i=0; public String getQuestions() throws SQLException { String result = ""; rsm = questions.getMetaData(); for (int i = 0; i < rsm.getColumnCount(); i++) { result += "<th>" + rsm.getColumnName(i + 1) + "</th>"; } if (!questions.isLast()) { questions.next(); System.out.println(i+1); result += "<tr>"; result += "<td>" + questions.getInt(1) + "</td>"; result += "<td>" + questions.getString(2) + "</td>"; result += "</tr>"; result += "<tr>"; sqlselect2.setValue(String.valueOf(questions.getInt(1))); answers = sqlselect2.Execute(); while (answers.next()) { result += "<tr> <td colspan='2'><input type='radio' name='answer' value='" + answers.getString(2) + "'> " + answers.getString(2) + "</td></tr>"; } result += "</tr>"; answers.close(); } return result; } this is the HTML: <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>JSP Page</title> </head> <body> <h1>JSP Page</h1> <jsp:useBean id="exam" class="exam.ExamQuestions"></jsp:useBean> <% exam.setConnection(); %> <form method="post"> <table > <%=exam.getQuestions()%> </table> <input type="submit" name="action" value="next"/> </form> <% String action = request.getParameter("action"); if ("next".equals(action)) { out.println(request.getParameter("answer")); } %> </body> </html>

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  • Install wireless router with cable modem - need authentication server?

    - by Paul
    I've bought a wireless router which I'm installing with a Telstra BigPond cable modem for a friend. As part of the setup I've got to a screen requesting username / password / authentication server for the cable modem They have contacted Telstra who supply the username / password and say that is all they need. They dont know anything about an authentication server. There are a couple of answers up on Whirlpool forum found through google but those answers are 4 years old. http://forums.whirlpool.net.au/forum-replies-archive.cfm/475258.html http://forums.whirlpool.net.au/forum-replies-archive.cfm/479615.html I havent tried them yet as I hoped to get actual answers before trundling over to my friends house again. Can anyone suggest, How to get information from Telstra support? (I realise this question maybe impossible to answer) What is the authentication server for Telstra BigPond for a user in Sydney Australia Are those whirlpool forum answers still valid? I guess if I dont get anything more here I'll try what it says on whirlpool and see what happens.

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  • Install wireless router with cable modem - need authentication server?

    - by Paul
    I've bought a wireless router which I'm installing with a Telstra BigPond cable modem for a friend. As part of the setup I've got to a screen requesting username / password / authentication server for the cable modem They have contacted Telstra who supply the username / password and say that is all they need. They dont know anything about an authentication server. There are a couple of answers up on Whirlpool forum found through google but those answers are 4 years old. http://forums.whirlpool.net.au/forum-replies-archive.cfm/475258.html http://forums.whirlpool.net.au/forum-replies-archive.cfm/479615.html I havent tried them yet as I hoped to get actual answers before trundling over to my friends house again. Can anyone suggest, How to get information from Telstra support? (I realise this question maybe impossible to answer) What is the authentication server for Telstra BigPond for a user in Sydney Australia Are those whirlpool forum answers still valid? I guess if I dont get anything more here I'll try what it says on whirlpool and see what happens.

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  • Use autocomplete in dropdown cells with Excel 2007?

    - by Martin
    I want to make a survey with Excel and I therefore have defined the cells for the answers as a dropdown cell which only accepts answers from a certain list, e. g.: The two Lists List1 and List2 (yellow cells) are the possible answers for the questions in Block 1.x resp. 2.x (blue) . There might be a block 4 with more questions, which again use List1 for their possible answers. My problem is: I'd like to be able to use the autocompleate feature to fill in the blue cells with the dropdown menu, so that the user only types 5 and it automatically expands to "5: extremely important" or "5: extremely difficult". According to my research on the www, this should be possible if I add the list with possible answers directly above the cells where autocomplete should work (I did this with the green helper cells which could be hidden) . But I have to enter at least 4 characters 5: e to get the autocompleted suggestion. Is there a way to make autocomplete already replace a "5" by the corresponding valid term? As the survey file shall be distributed to a lot of people "outside", I can not use VBA magic because it may be blocked on their computer and might not work. EDIT: it seems to have to do with the numbers I use: If I'd start my List items with A, B, C instead of 1, 2, 3, it would work perfectly. Excel seems to ignore the pure numbers when they are entered and does not try to autocomplete them.. is there a workaround? (I hope it is clear what I want, it seems a little difficult to explain.)

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  • Resolve Instructional Webcast Series

    - by Get Proactive Customer Adoption Team
    Untitled Document Catch the Express—Register for an Instructional Webcast Oracle Proactive Support’s ‘Get Proactive’ message to customers underscores the benefits they’ll obtain by leveraging the Prevent, Resolve and Upgrade capabilities available across the suite of Oracle Products. Our goal in Proactive Support is to show customers how to ‘Get Proactive’ and achieve success by leveraging the latest tools, knowledge, and best practices available to manage your applications and technology more proactively. Most importantly, we want to ensure that customers are proficient in the use of these proactive capabilities. To help you gain this proficiency, we’ve recently launched a series of instructional webcasts that we call the “Resolve Series.” This series consists of both live and on-demand webcasts, and features some of the key proactive capabilities that customers can leverage to resolve their own problems. We launched the first phase of the series in July, and focused on finding answers using the My Oracle Support portal. Among the topics covered in those sessions were best practices for searching the knowledge base, leveraging communities to find answers faster, and other proactive features of My Oracle Support The second phase of the series is set to kick off in September. This phase will include product specific sessions designed to provide customers who use the product with the skills and knowledge required to leverage some of the most important capabilities found under the “RESOLVE” category of our proactive portfolio on My Oracle Support. These webcasts will feature Subject Matter Experts demonstrating how to use the tools and capabilities, discussing best practices, and providing answers to any questions you might have. In addition, hands-on labs will be included in some of the sessions, allowing you to practice applying what you’ve just learned. Whether you are a new customer or you’ve worked with Oracle Support for years, you’ll discover new information and techniques to help you work more efficiently and keep your systems running smoothly. Leverage this opportunity to learn best practices and get the inside track on finding answers fast by using the right tools at the right time. Make sure to take advantage of these webcasts and maximize the value you receive from your Oracle Premier Support investment. See the full schedule of events and register for sessions.

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  • How can I make myself better at programming working at a shi* job ?

    - by Scrooge
    I recently graduated with an Engineering degree in Computer Science, but my employer (a mid-sized software company) is not using my logical and programming skills. I want to move to a better opportunity but how do I do that since my experience here is not going to count as much? How do I get a better programming job? The worst part is that I am still reading from books (and not writing code myself) even after I have started working. They are paying me a standard entry level Indian IT job rate but I really dont care. It's not worth it. Please advise as to how I can do something worthwhile. (I have studied C++; Core Java; Ruby On Rails ..made a couple of academic projects but no relevant practical real world experience). Just to make things easier .. let me list a few basic queries How I get better at programming without a good project at my company? Please suggest projects where I can learn to write practical code (platform doesn't matter) Best place to take part in open source development? Is it possible that I earn slightly more while I learn? (apart from my sh** job I mean) What kind of practical projects are best suited for me? (ie for an entry level programmer)

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  • Why is math taught "backwards"? [closed]

    - by Yorirou
    A friend of mine showed me a pretty practical Java example. It was a riddle. I got excited and quickly solved the problem. After it, he showed me the mathematical explanation of my solution (he proved why is it good), and it was completely clear for me. This seems like natural approach for me: solve problems, and generalize. This is very familiar to me, I do it all the time when I am programming: I write a function. When I have to write a similar function, I generalize the problem, grab the generic parts, and refactor them to a function, and solve the original problems as a specialization of the general function. At the university (or at least where I study), things work backwards. The professors shows just the highest possible level of the solutions ("cryptic" mathematical formulas). My problem is that this is too abstract for me. There is no connection of my previous knowledge (== reality in my sense), so even if I can understand it, I can't really learn it properly. Others are learning these formulas word-by-word, and get good grades, since they can write exactly the same to the test, but this is not an option for me. I am a curious person, I can learn interesting things, but I can't learn just text. My brain is for storing toughts, not strings. There are proofs for the theories, but they are also really hard to understand because of this, and in most of the cases they are omitted. What is the reason for this? I don't understand why is it a good idea to show the really high level of abstraction and then leave the practical connections (or some important ideas / practical motivations) out?

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  • SQL SERVER – 3 Simple Puzzles – Need Your Suggestions

    - by pinaldave
    Last Month, I have posted three Simple Puzzles and I got very good response. I think there can be many interesting answers there. I would like to request all of you to take part the puzzles and provide your answer. I plant to consolidate answers and publish all the valid answers on this blog with due credit. SQL SERVER – Challenge – Puzzle – Usage of FAST Hint SQL SERVER – Puzzle – Challenge – Error While Converting Money to Decimal SQL SERVER – Challenge – Puzzle – Why does RIGHT JOIN Exists I am also thinking that after such a long time we should have word Database Developer (DBD) just like Database Administrator (DBA) in our dictionary. I have also created pole where I talk about this subject. SQL SERVER – Are you a Database Administrator or a Database Developer? ?Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Oracle Utilities Framework Batch Easy Steps

    - by ACShorten
    Oracle Support have compiled a list of common Questions and Answers for Batch Processing in Oracle Utilities Application Framework. Customers and partners should take a look at these questions and answers before posting any question to support to save time. The Knowledge Base article is available from My Oracle Support under FW - Oracle Utilities Framework Batch Easy Steps (Doc ID 1306282.1). This article answers the questions but also posts links to other documents including the Batch Best Practices for Oracle Utilities Application Framework based products (Doc Id: 836362.1) and Oracle Utilities CCB Batch Operations And Configuration Guide (Doc Id: 753301.1) for more detailed information and explanation. Customers of Oracle Utilities Meter Data Management V2.0 and above, Oracle Utilities Mobile Workforce Management V2.0 and above, Oracle Enterprise Taxation and Policy Management V2.0 and above, and Oracle Utilities Smart Grid Gateway V2.0 (all editions) and above should refer to the Batch Server Administration Guide shipped with their products on eDelivery instead of using Doc Id: 753301.1.

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  • How to code review without offending other developers [duplicate]

    - by Justin984
    This question already has an answer here: How to deal with someone who dislikes the idea of code reviews? 6 answers How can I tactfully suggest improvements to others' badly designed code during review? 14 answers How do I approach a coworker about his or her code quality? 12 answers I work on a team that does frequent code reviews. But it seems like more of a formality than anything. No one really points out problems in the code for fear of offending other developers. The few times I've tried to ask for changes were met with very defensive and reluctant attitudes. This is of course not good. Not only are we spending the time to code review, but we're getting literally zero value from it. Is this an issue that needs to be addressed by individual developers, or are there techniques for suggesting changes without stepping on other people's toes?

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  • Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

    - by Mike
    EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

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  • how useful is Turing completeness? are neural nets turing complete?

    - by Albert
    While reading some papers about the Turing completeness of recurrent neural nets (for example: Turing computability with neural nets, Hava T. Siegelmann and Eduardo D. Sontag, 1991), I got the feeling that the proof which was given there was not really that practical. For example the referenced paper needs a neural network which neuron activity must be of infinity exactness (to reliable represent any rational number). Other proofs need a neural network of infinite size. Clearly, that is not really that practical. But I started to wonder now if it does make sense at all to ask for Turing completeness. By the strict definition, no computer system nowadays is Turing complete because none of them will be able to simulate the infinite tape. Interestingly, programming language specification leaves it most often open if they are turing complete or not. It all boils down to the question if they will always be able to allocate more memory and if the function call stack size is infinite. Most specification don't really specify this. Of course all available implementations are limited here, so all practical implementations of programming languages are not Turing complete. So, what you can say is that all computer systems are just equally powerful as finite state machines and not more. And that brings me to the question: How useful is the term Turing complete at all? And back to neural nets: For any practical implementation of a neural net (including our own brain), they will not be able to represent an infinite number of states, i.e. by the strict definition of Turing completeness, they are not Turing complete. So does the question if neural nets are Turing complete make sense at all? The question if they are as powerful as finite state machines was answered already much earlier (1954 by Minsky, the answer of course: yes) and also seems easier to answer. I.e., at least in theory, that was already the proof that they are as powerful as any computer.

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  • SQL SERVER – Quiz and Video – Introduction to Hierarchical Query using a Recursive CTE

    - by pinaldave
    This blog post is inspired from SQL Queries Joes 2 Pros: SQL Query Techniques For Microsoft SQL Server 2008 – SQL Exam Prep Series 70-433 – Volume 2.[Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to Hierarchical Query using a Recursive CTE – A Primer. In the article we discussed various basics terminology of the CTE. The article further covers following important concepts of common table expression. What is a Common Table Expression (CTE) Building a Recursive CTE Identify the Anchor and Recursive Query Add the Anchor and Recursive query to a CTE Add an expression to track hierarchical level Add a self-referencing INNER JOIN statement Above six are the most important concepts related to CTE and SQL Server.  There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced  concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1) You have an employee table with the following data. EmpID FirstName LastName MgrID 1 David Kennson 11 2 Eric Bender 11 3 Lisa Kendall 4 4 David Lonning 11 5 John Marshbank 4 6 James Newton 3 7 Sally Smith NULL You need to write a recursive CTE that shows the EmpID, FirstName, LastName, MgrID, and employee level. The CEO should be listed at Level 1. All people who work for the CEO will be listed at Level 2. All of the people who work for those people will be listed at Level 3. Which CTE code will achieve this result? WITH EmpList AS (SELECT Boss.EmpID, Boss.FName, Boss.LName, Boss.MgrID, 1 AS Lvl FROM Employee AS Boss WHERE Boss.MgrID IS NULL UNION ALL SELECT E.EmpID, E.FirstName, E.LastName, E.MgrID, EmpList.Lvl + 1 FROM Employee AS E INNER JOIN EmpList ON E.MgrID = EmpList.EmpID) SELECT * FROM EmpList WITH EmpListAS (SELECT EmpID, FirstName, LastName, MgrID, 1 as Lvl FROM Employee WHERE MgrID IS NULL UNION ALL SELECT EmpID, FirstName, LastName, MgrID, 2 as Lvl ) SELECT * FROM BossList WITH EmpList AS (SELECT EmpID, FirstName, LastName, MgrID, 1 as Lvl FROM Employee WHERE MgrID is NOT NULL UNION SELECT EmpID, FirstName, LastName, MgrID, BossList.Lvl + 1 FROM Employee INNER JOIN EmpList BossList ON Employee.MgrID = BossList.EmpID) SELECT * FROM EmpList 2) You have a table named Employee. The EmployeeID of each employee’s manager is in the ManagerID column. You need to write a recursive query that produces a list of employees and their manager. The query must also include the employee’s level in the hierarchy. You write the following code segment: WITH EmployeeList (EmployeeID, FullName, ManagerName, Level) AS ( –PICK ANSWER CODE HERE ) SELECT EmployeeID, FullName, ” AS [ManagerID], 1 AS [Level] FROM Employee WHERE ManagerID IS NULL UNION ALL SELECT emp.EmployeeID, emp.FullName mgr.FullName, 1 + 1 AS [Level] FROM Employee emp JOIN Employee mgr ON emp.ManagerID = mgr.EmployeeId SELECT EmployeeID, FullName, ” AS [ManagerID], 1 AS [Level] FROM Employee WHERE ManagerID IS NULL UNION ALL SELECT emp.EmployeeID, emp.FullName, mgr.FullName, mgr.Level + 1 FROM EmployeeList mgr JOIN Employee emp ON emp.ManagerID = mgr.EmployeeId Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 1 2) 2 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Select distinct from multiple fields using sql

    - by Bryan
    I have 5 columns corresponding to answers in a trivia game database - right, wrong1, wrong2, wrong3, wrong4 I want to return all possible answers without duplicates. I was hoping to accomplish this without using a temp table. Is it possible to use something similar to this?: select c1, c2, count(*) from t group by c1, c2 But this returns 3 columns. I would like one column of distinct answers. Thanks for your time

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  • how do I update the date type column?

    - by Muhammad Hammad
    update answers a1 set a1.FilingDate=( select date_sub( a2.FilingDate ,Interval 1000 Year) as FilingDate from answers a2 where Year(a2.FilingDate)>=3000 ) where Year(a1.FilingDate)>=3000 but it gives me the following error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'update answers a1 set a1.FilingDate=( select date_sub(a2.FilingDate,Interval 10' at line 1 Can anyone tell me about the issue and its solution?

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  • MYSQL Convert rows to columns performance problem

    - by Tarski
    I am doing a query that converts rows to columns similar to this post but have encountered a performance problem. Here is the query:- SELECT Info.Customer, Answers.Answer, Answers.AnswerDescription, Details.Code1, Details.Code2, Details.Code3 FROM Info LEFT OUTER JOIN Answers ON Info.AnswerID = Answers.AnswerID LEFT OUTER JOIN (SELECT ReferenceNo, MAX(CASE DetailsIndicator WHEN 'cde1' THEN DetailsCode ELSE NULL END ) Code1, MAX(CASE DetailsIndicator WHEN 'cde2' THEN DetailsCode ELSE NULL END ) Code2, MAX(CASE DetailsIndicator WHEN 'cde3' THEN DetailsCode ELSE NULL END ) Code3 FROM DetailsData GROUP BY ReferenceNo) Details ON Info.ReferenceNo = Details.ReferenceNo There are less than 300 rows returned, but the Details table is about 180 thousand rows. The query takes 45 seconds to run and needs to take only a few seconds. When I type show processlist; into MYSQL it is hanging on "Sending Data". Any thoughts as to what the performance problem might be?

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