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• Checkers AI Algorithm

  - by John

  I am making an AI for my checkers game and I'm trying to make it as hard as possible. Here is the current criteria for a move on the hardest difficulty: 1: Look For A Block: This is when a piece is being threatened and another piece can be moved in behind it to protect it. Here is an example: Black Moves |W| |W| |W| |W| | | |W| |W| |W| |W| |W| | | |W| |W| | | | | |W| | | | | | | | | |B| | | | | |B| | | |B| |B| |B| |B| |B| |B| | | |B| |B| |B| |B| White Blocks |W| |W| |W| |W| | | |W| | | |W| |W| |W| |W| |W| |W| | | | | |W| | | | | | | | | |B| | | | | |B| | | |B| |B| |B| |B| |B| |B| | | |B| |B| |B| |B| 2: Move pieces out of danger: if any piece is being threatened, and a piece cannot block for that piece, then it will attempt to move out of the way. If the piece cannot move out of the way without still being in danger, the computer ignores the piece. 3: If the computer player owns any kings, it will attempt to 'hunt down' enemy pieces on the board, if no moves can be made that won't in danger the king or any other pieces, the computer ignores this rule. 4: Any piece that is owned by the computer that is in column 1 or 6 will attempt to go to a side. When a piece is in column 0 or 7, it is in a very strategic position because it cannot get captured while it is in either of these columns 5: It makes an educated random move, the move will not indanger the piece that is moving or any piece that is on the board. 6: If none of the above are possible it makes a random move. This question is not really specific to any language but if all examples could be in Java that would be great, considering this app is written in android. Does anyone see any room for improvement in this algorithm? Anything that would make it better at playing checkers?

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• Panning with the OpenGL Camera / View Matrix

  - by Pris

  I'm gonna try this again I've been trying to setup a simple camera class with OpenGL but I'm completely lost and I've made zero progress creating anything useful. I'm using modern OpenGL and the glm library for matrix math. To get the most basic thing I can think of down, I'd like to pan an arbitrarily positioned camera around. That means move it along its own Up and Side axes. Here's a picture of a randomly positioned camera looking at an object: It should be clear what the Up (Green) and Side (Red) vectors on the camera are. Even though the picture shows otherwise, assume that the Model matrix is just the identity matrix. Here's what I do to try and get it to work: Step 1: Create my View/Camera matrix (going to refer to it as the View matrix from now on) using glm::lookAt(). Step 2: Capture mouse X and Y positions. Step 3: Create a translation matrix mapping changes in the X mouse position to the camera's Side vector, and mapping changes in the Y mouse position to the camera's Up vector. I get the Side vector from the first column of the View matrix. I get the Up vector from the second column of the View matrix. Step 4: Apply the translation: viewMatrix = glm::translate(viewMatrix,translationVector); But this doesn't work. I see that the mouse movement is mapped to some kind of perpendicular axes, but they're definitely not moving as you'd expect with respect to the camera. Could someone please explain what I'm doing wrong and point me in the right direction with this camera stuff?

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• SQL SERVER – Finding Size of a Columnstore Index Using DMVs

  - by pinaldave

  Columnstore Index is one of my favorite enhancement in SQL Server 2012. A columnstore index stores each column in a separate set of disk pages, rather than storing multiple rows per page as data traditionally has been stored. In case of the row store indexes multiple pages will contain multiple rows of the columns spanning across multiple pages. Whereas in case of column store indexes multiple pages will contain (multiple) single columns.  Columnstore Indexes are compressed by default and occupies much lesser space than regular row store index by default. One of the very common question I often see is need of the list of columnstore index along with their size and corresponding table name. I quickly re-wrote a script using DMVs sys.indexes and sys.dm_db_partition_stats. This script gives the size of the columnstore index on disk only. I am sure there will be advanced script to retrieve details related to components associated with the columnstore index. However, I believe following script is sufficient to start getting an idea of columnstore index size.  SELECT OBJECT_SCHEMA_NAME(i.OBJECT_ID) SchemaName, OBJECT_NAME(i.OBJECT_ID ) TableName, i.name IndexName, SUM(s.used_page_count) / 128.0 IndexSizeinMB FROM sys.indexes AS i INNER JOIN sys.dm_db_partition_stats AS S ON i.OBJECT_ID = S.OBJECT_ID AND I.index_id = S.index_id WHERE  i.type_desc = 'NONCLUSTERED COLUMNSTORE' GROUP BY i.OBJECT_ID, i.name Here is my introductory article written on SQL Server Fundamentals of Columnstore Index. Create a sample columnstore index based on the script described in the earlier article. It will give the following results. Please feel free to suggest improvement to script so I can further modify it to accommodate enhancements. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: ColumnStore Index

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• Sql Server Prevent Saving Changes That Require Table to be Re-created

  When working with SQL Server Management studio, if you use the Design view of a table and attempt to make a change that will require the table to be dropped and re-added, you may receive an error message like this one: Saving changes is not permitted.  The changes you have made require the following tables to be dropped and re-created.  You have either made changes to a table that cant be re-created or enabled the option Prevent saving changes that require the table to be re-created. In truth, its quite likely that you didnt enable such an option, despite the error dialogs accusations, as it is enabled by default when you install SQL Management Studio.  You can learn more about the issue in the KB article, Error message when you try to save a table in SQL Server 2008: Saving changes is not permitted. Warning: As the above article states, it is not recommended that you turn off this option (at least not permanently), as it will ensure that you do not accidentally change the schema of a table such that data is lost.  Do so at your peril. The simplest way to bypass this error is to go into Option Designers and uncheck the option Prevent saving changes that require table re-creation.  See the screenshot below. The main reason why you will see this error is if you attempted to do any of the following to the table whose design you are saving: Change the Allow Nulls setting for a column Reorder columns Change any columns data type Add a new column The recommended workaround is to script out the changes to a SQL file and execute them by hand, or to simply write out your own T-SQL to make the changes. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• How To Use AutoFill on a Google Docs Spreadsheet [Quick Tips]

  - by The Geek

  Have you ever wanted to fill an entire row or column with a series of values? If you’re an Excel user, you can do the same thing in Google Docs. If you haven’t used either, here’s the quick way to do it. Just type in a couple of numbers in sequence… 1 2 3 works pretty well. You could also put them across a row instead of down a column. Then move your mouse over the dot in the corner until the pointer changes, then just drag it downward (or if you are filling a row instead, you can drag it to the right). Let go of the mouse, and your data will be automatically filled in. You could also make it skip by 1 instead, like 2 4 6 8, etc… It all works the same way. Sadly there’s no really advanced options like Excel has, but for most uses, this is good enough. Also, we’re aware this is a very simple tip for most of you, but we’re trying to help the beginners out as well! Similar Articles Productive Geek Tips Integrate Google Docs with Outlook the Easy WayHow To Export Documents from Google Docs to Your ComputerHow To Monitor Sites Without an RSS Feed Using FirefoxGeek Software: Use DeliCount to Get Site-wide del.icio.us Bookmark CountsMake Excel 2007 Read Spreadsheets To You TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Combine MP3 Files Easily QuicklyCode Provides Cheatsheets & Other Programming Stuff Download Free MP3s from Amazon Awe inspiring, inter-galactic theme (Win 7) Case Study – How to Optimize Popular Wordpress Sites Restore Hidden Updates in Windows 7 & Vista

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• Computer Bugs - Etymology and Entomology

  - by PointsToShare

  Whatever bugs you My wife and I used to take some of our summer vacation I a cabin on the shore of Lake Atsion in NJ. I t is a delightful place in the Wharton forest with Brown yet fresh water, where we would canoe, swim and enjoy true rest. Alas, in the last few years, yellow flies also discovered the area’s pastoral delights and came in hoards to bug us. So much so that we had to give up. As a computer programmer I abhor bugs. The bugs that bug me – except the pesky yellow flies – are program bugs , a specific variety of computer bugs. You can find an excellent take on the etymology of the word ‘bug” in this delightful monogram: http://www.jamesshuggins.com/h/tek1/first_computer_bug.htm In my youth, I worked on Burroughs computers. Unlike their IBM brethren, the Burroughs used a 96 column card. The cards were much smaller than the 80 column IBM cards. We wrote our programs on coding sheets and then a key-punch operator transcribed them into punched cards. These were fed into a card reader and compiled. The compiler would notify us of compiler errors or bugs, but it was not always easy to get the meaning of the message. My friend Mark Wildt, also a Burroughs veteran, gave me an old punched card from one of his programs. Obviously a bug!! Here It Is!! That’s All Folks!

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• Cross Apply Ambiguity

  - by Dave Ballantyne

  Cross apply (and outer apply)  are a very welcome addition to the TSQL language.  However, today after a few hours of head scratching, I have found an simple issue which could cause big big problems. What would you expect from this statement ? select * from sys.objects b join sys.objects a on a.object_id = object_id No prizes for guessing SQL server errors with “Ambiguous column name 'object_id'”. What would you expect from this statement ? Select * from sys.objects a cross apply( Select * from sys.objects b where b.object_id = object_id) as c Surprisingly, perhaps, the result is a cross join of sys.objects.  Well, what happened there ? If you look at the apply statement, within the where clause, only one of the conditions is qualified with a table name.  This meant that is has be interpreted as “b.object_id = b.object_id” causing the cross apply to have no join the the parent sys.objects table and causing the cross join. The fix is , obviously, simple Select * from sys.objects a cross apply( Select * from sys.objects b where b.object_id = a.object_id) as c So why no “Ambiguous column name ” error ?  I’ve raised a connect item on this issue here.

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• How can I cull non-visible isometric tiles?

  - by james

  I have a problem which I am struggling to solve. I have a large map of around 100x100 tiles which form an isometric map. The user is able to move the map around by dragging the mouse. I am trying to optimize my game only to draw the visible tiles. So far my code is like this. It appears to be ok in the x direction, but as soon as one tile goes completely above the top of the screen, the entire column disappears. I am not sure how to detect that all of the tiles in a particular column are outside the visible region. double maxTilesX = widthOfScreen/ halfTileWidth + 4; double maxTilesY = heightOfScreen/ halfTileHeight + 4; int rowStart = Math.max(0,( -xOffset / halfTileWidth)) ; int colStart = Math.max(0,( -yOffset / halfTileHeight)); rowEnd = (int) Math.min(mapSize, rowStart + maxTilesX); colEnd = (int) Math.min(mapSize, colStart + maxTilesY); EDIT - I think I have solved my problem, but perhaps not in a very efficient way. I have taken the center of the screen coordinates, determined which tile this corresponds to by converting the coordinates into cartesian format. I then update the entire box around the screen.

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• Dependency Analyser

  - by tsutha

  I have been watching 3 videos put together by SSIS team on Dependency Analyser. I am happy Microsoft have made an effort to do something about it. I have been asking for this feature since SQL 2005 TAP. Still a long way to go before they catch up with competetion. It looks like it currently supports SSIS and SQL dependencies. Release note states its still in development and support only limited sets of tasks. You still would not know the impact of dropping a column on cubes, reports etc. I hope that changes by the time RTM comes out. I am struggling to understand why it is impossible to do it across the solution. Ideally if you have a BI solution which holds DB, SSIS, SSAS, SSRS & PPS projects I would like to right click and execute a dependency analyser, stating what impact would have if I drop / rename a specific column. Has anyone else looked at it and what are your thoughts? ThanksSutha  

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• Alternate method to dependent, nested if statements to check multiple states

  - by octopusgrabbus

  Is there an easier way to process multiple true/false states than using nested if statements? I think there is, and it would be to create a sequence of states, and then use a function like when to determine if all states were true, and drop out if not. I am asking the question to make sure there is not a preferred Clojure way to do this. Here is the background of my problem: I have an application that depends on quite a few input files. The application depends on .csv data reports; column headers for each report (.csv files also), so each sequence in the sequence of sequences can be zipped together with its columns for the purposes of creating a smaller sequence; and column files for output data. I use the following functions to find out if a file is present: (defn kind [filename] (let [f (File. filename)] (cond (.isFile f) "file" (.isDirectory f) "directory" (.exists f) "other" :else "(cannot be found)" ))) (defn look-for [filename expected-type] (let [find-status (kind-stat filename expected-type)] find-status)) And here are the first few lines of a multiple if which looks ugly and is hard to maintain: (defn extract-re-values "Plain old-fashioned sub-routine to process real-estate values / 3rd Q re bills extract." [opts] (if (= (utl/look-for (:ifm1 opts) "f") 0) ; got re columns? (if (= (utl/look-for (:ifn1 opts) "f") 0) ; got re data? (if (= (utl/look-for (:ifm3 opts) "f") 0) ; got re values output columns? (if (= (utl/look-for (:ifm4 opts) "f") 0) ; got re_mixed_use_ratio columns? (let [re-in-col-nams (first (utl/fetch-csv-data (:ifm1 opts))) re-in-data (utl/fetch-csv-data (:ifn1 opts)) re-val-cols-out (first (utl/fetch-csv-data (:ifm3 opts))) mu-val-cols-out (first (utl/fetch-csv-data (:ifm4 opts))) chk-results (utl/chk-seq-len re-in-col-nams (first re-in-data) re-rec-count)] I am not looking for a discussion of the best way, but what is in Clojure that facilitates solving a problem like this.

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• Grouping a comma separated value on common data [closed]

  - by Ankit

  I have a table with col1 id int, col2 as varchar (comma separated values) and column 3 for assigning group to them. Table looks like col1 col2 group .............................. 1 2,3,4 2 5,6 3 1,2,5 4 7,8 5 11,3 6 22,8 This is only the sample of real data, now I have to assign a group no to them in such a way that output looks like col1 col2 group .............................. 1 2,3,4 1 2 5,6 1 3 1,2,5 1 4 7,8 2 5 11,3 1 6 22,8 2 The logic for assigning group no is that every similar comma separated value of string in col2 have to be same group no as every where in col2 where '2' is there it has to be same group no but the complication is that 2,3,4 are together so they all three int value if found in any where in col2 will be assigned same group. The major part is 2,3,4 and 1,2,5 both in col2 have 2 so all int 1,2,3,4,5 have to assign same group no. Tried store procedure with match against on col2 but not getting desired result Most imp (I can't use normalization, because I can't afford to make new table from my original table which have millions of records), even normalization is not helpful in my context. This question is also on stackoverflow with bounty on this link Achieved so far:- I have set the group column auto increment and then wrote this procedure:- BEGIN declare cil1_new,col2_new,group_new int; declare done tinyint default 0; declare group_new varchar(100); declare cur1 cursor for select col1,col2,`group` from company ; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1; open cur1; REPEAT fetch cur1 into col1_new,col2_new,group_new; update company set group=group_new where match(col2) against(concat("'",col2_new,"'")); until done end repeat; close cur1; select * from company; END This procedure is working, no syntax mistake but the problem is that I am not achieving the desired result exactly.

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• Compute the AES-encryption key given the plaintext and its ciphertext?

  - by Null Pointers etc.

  I'm tasked with creating database tables in Oracle which contain encrypted strings (i.e., the columns are RAW). The strings are encrypted by the application (using AES, 128-bit key) and stored in Oracle, then later retrieved from Oracle and decrypted (i.e., Oracle itself never sees the unencrypted strings). I've come across this one column that will be one of two strings. I'm worried that someone will notice and presumably figure out what those two values to figure out the AES key. For example, if someone sees that the column is either Ciphertext #1 or #2: Ciphertext #1: BF,4F,8B,FE, 60,D8,33,56, 1B,F2,35,72, 49,20,DE,C6. Ciphertext #2: BC,E8,54,BD, F4,B3,36,3B, DD,70,76,45, 29,28,50,07. and knows the corresponding Plaintexts: Plaintext #1 ("Detroit"): 44,00,65,00, 74,00,72,00, 6F,00,69,00, 74,00,00,00. Plaintext #2 ("Chicago"): 43,00,68,00, 69,00,63,00, 61,00,67,00, 6F,00,00,00. can he deduce that the encryption key is "Buffalo"? 42,00,75,00, 66,00,66,00, 61,00,6C,00, 6F,00,00,00. I'm thinking that there should be only one 128-bit key that could convert Plaintext #1 to Ciphertext #1. Does this mean I should go to a 192-bit or 256-bit key instead, or find some other solution? (As an aside, here are two other ciphertexts for the same plaintexts but with a different key.) Ciphertext #1 A ("Detroit"): E4,28,29,E3, 6E,C2,64,FA, A1,F4,F4,96, FC,18,4A,C5. Ciphertext #2 A ("Chicago"): EA,87,30,F0, AC,44,5D,ED, FD,EB,A8,79, 83,59,53,B7.

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• How do I print values of an array in Three Rows?

  - by Ramkumar

  I need this output.. 1 3 5 2 4 6 I want to use array function like array(1,2,3,4,5,6). If I edit this array like array(1,2,3), it means the output need to show like 1 2 3 The concept is maximum 3 column only. If we give array(1,2,3,4,5), it means the output should be 1 3 5 2 4 Suppose we will give array(1,2,3,4,5,6,7,8,9), then it means output is 1 4 7 2 5 8 3 6 9 that is, maximum 3 column only. Depends upon the the given input, the rows will be created with 3 columns. Is this possible with PHP? I am doing small Research & Development in array functions. I think this is possible. Will you help me? For more info: * input: array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15) * output: 1 6 11 2 7 12 3 8 13 4 9 14 5 10 15

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• Visual WebGui launches a new prize-winning challenge for developers

  - by Webgui

  Gizmox is announcing a ListView Challenge where developers can participate by creating and submitting their own implementations of the new extended ListView. "its quite amazing what you can do with it. It opens a lot of new ways to present data in a better and more userfriendly way," says one of the VWG community members who built a three level hierarchal ListView. Watch the hierarchal ListView demo by Visualizer Those ListView implementations will be reviewed and rated and the winner will win a free Professional Studio license $750 worth. The 5 top rated codes will entitle their developers for a cool new T-shirt. The new v6.4 introduces new capabilities with its extended ListView Control. Enter the Challenge The Collapsible Panel enhancement of the ListView Control, along with the Column Type Control, open up the possibilities for potential usage of the ListView control for data display, data entry and as the Collapsible Panel can contain whatever control you like, it can as well contain other ListView controls, thus making it possible to create Hierarchial ListView display of unlimited number of levels. The first enhancement is the introduction of a new column type Control which opens up the possibility for a ListView cell to contain controls like CheckBox, ComboBox, ListBox or even TabControl, Form or another ListView as the contents of that particular cell. This means that the ListView is no longer a display-only control, but has the full potential of being a full blown data entry control as well. The second major enhancement is the introduction of ListViewPanelItem. The ListViewPanelItem behaves exactly the same as it‘s predecessor, the ListViewItem, and in additon it has a Panel Control attached to it, seperate panel for each row in the ListView. This new Panel can be either expanded (visible) or not (hidden) and when expanded, will fill the full width of the ListView, but has adjustable height. Watch a webcast about the extended ListView

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• Should you create a class within a method?

  - by Amndeep7

  I have made a program using Java that is an implementation of this project: http://nifty.stanford.edu/2009/stone-random-art/sml/index.html. Essentially, you create a mathematical expression and, using the pixel coordinate as input, make a picture. After I initially implemented this in serial, I then implemented it in parallel due to the fact that if the picture size is too large or if the mathematical expression is too complex (especially considering the fact that I made the expression recursively), it takes a really long time. During this process, I realized that I needed two classes which implemented the Runnable interface as I had to put in parameters for the run method, which you aren't allowed to do directly. One of these classes ended up being a medium sized static inner class (not large enough to make an independent class file for it though). The other though, just needed a few parameters to determine some indexes and the size of the for loop that I was making run in parallel - here it is: class DataConversionRunnable implements Runnable { int jj, kk, w; DataConversionRunnable(int column, int matrix, int wid) { jj = column; kk = matrix; w = wid; } public void run() { for(int i = 0; i < w; i++) colorvals[kk][jj][i] = (int) ((raw[kk][jj][i] + 1.0) * 255 / 2.0); increaseCounter(); } } My question is should I make it a static inner class or can I just create it in a method? What is the general programming convention followed in this case?

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• Recasting and Drawing in SDL

  - by user1078123

  I have some code that essentially draws a column on the screen of a wall in a raycasting-type 3d engine. I am trying to optimize it, as it takes about 10 milliseconds do draw a million pixels using this, and the vast majority of game time is spent in this loop. However, I don't quite understand what's occurring, particularly the recasting (I modified the "pixel manipulation" sample code from the SDL documentation). "canvas" is the surface I am drawing to, and "hello" is the surface containing the texture for the column. int c = (curcol)* canvas->format->BytesPerPixel; void *canvaspixels = canvas->pixels; Uint16 texpitch = hello->pitch; int lim = (drawheight +startdraw) * canvpitch +c + (int) canvaspixels; Uint8 *k = (Uint8 *)hello->pixels + (hit)* hello->format->BytesPerPixel; for (int j= (startdraw)*(canvpitch)+c + (int) canvaspixels; (j< lim); j+= canvpitch){ Uint8 *q = (Uint8 *) ((int(h))*(texpitch)+k); *(Uint32 *)j = *(Uint32 *)q; h += s; } We have void pointers (not sure how those are even represented), 8, 16, and 32 bit ints (h and s are floats), all being intermingled, and while it works, it is quite confusing.

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• Defining formula through user interface in user form

  - by BriskLabs Pakistan

  I am a student and developing a simple assignment - windows form application in visual studio 2010. The application is suppose to construct formulas as per user requirement. The process: It has to pick data from columns of Microsoft Access database and the user should be able to pick the data by column name like we do in a drop down menu. and create reusable formulas in it ( configure it once and can change it again). followings are column titles from database that can be picked for example. e.g Col -1 : Marks in Maths Col -2 : Total Marks in Maths Col -3 : Marks in science Col -4 : Total marks in science Finally we should be able to construct any formula in the UI like (Col 1 + Col 3 ) / ( col 2 + col 4) = Formula 1 once this is formula is set saved and a name is assigned to it by user. he/she can use the formula and results shall appear in a window below. i.e He would be able to calculate his desired figures (formula) by only manipulating underlying data on the UI layer....choose the data for a period and apply the formula and get the answer Problem: It looks like I have to create an app where rules are set through UI....... this means no stored procedures are required in SQL.... please suggest the right approach.

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• Execution plan warnings–All that glitters is not gold

  - by Dave Ballantyne

  In a previous post, I showed you the new execution plan warnings related to implicit and explicit warnings.  Pretty much as soon as i hit ’post’,  I noticed something rather odd happening. This statement : select top(10) SalesOrderHeader.SalesOrderID, SalesOrderNumberfrom Sales.SalesOrderHeaderjoin Sales.SalesOrderDetail on SalesOrderHeader.SalesOrderID = SalesOrderDetail.SalesOrderID   Throws the “Type conversion may affect cardinality estimation” warning.     Ive done no such conversion in my statement why would that be ?  Well, SalesOrderNumber is a computed column , “(isnull(N'SO'+CONVERT([nvarchar](23),[SalesOrderID],0),N'*** ERROR ***'))”,  so thats where the conversion is.   Wait!!! Am i saying that every type conversion will throw the warning ?  Thankfully, no.  It only appears for columns that are used in predicates ,even if the predicate / join condition is fine ,  and the column is indexed ( and/or , presumably has statistics).    Hopefully , this wont lead to to many wild goose chases, but is definitely something to bear in mind.  If you want to see this fixed then upvote my connect item here.

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• Database Migration Scripts: Getting from place A to place B

  - by Phil Factor

  We’ll be looking at a typical database ‘migration’ script which uses an unusual technique to migrate existing ‘de-normalised’ data into a more correct form. So, the book-distribution business that uses the PUBS database has gradually grown organically, and has slipped into ‘de-normalisation’ habits. What’s this? A new column with a list of tags or ‘types’ assigned to books. Because books aren’t really in just one category, someone has ‘cured’ the mismatch between the database and the business requirements. This is fine, but it is now proving difficult for their new website that allows searches by tags. Any request for history book really has to look in the entire list of associated tags rather than the ‘Type’ field that only keeps the primary tag. We have other problems. The TypleList column has duplicates in there which will be affecting the reporting, and there is the danger of mis-spellings getting there. The reporting system can’t be persuaded to do reports based on the tags and the Database developers are complaining about the unCoddly things going on in their database. In your version of PUBS, this extra column doesn’t exist, so we’ve added it and put in 10,000 titles using SQL Data Generator. /* So how do we refactor this database? firstly, we create a table of all the tags. */IF  OBJECT_ID('TagName') IS NULL OR OBJECT_ID('TagTitle') IS NULL  BEGIN  CREATE TABLE  TagName (TagName_ID INT IDENTITY(1,1) PRIMARY KEY ,     Tag VARCHAR(20) NOT NULL UNIQUE)  /* ...and we insert into it all the tags from the list (remembering to take out any leading spaces */  INSERT INTO TagName (Tag)     SELECT DISTINCT LTRIM(x.y.value('.', 'Varchar(80)')) AS [Tag]     FROM     (SELECT  Title_ID,          CONVERT(XML, '<list><i>' + REPLACE(TypeList, ',', '</i><i>') + '</i></list>')          AS XMLkeywords          FROM   dbo.titles)g    CROSS APPLY XMLkeywords.nodes('/list/i/text()') AS x ( y )  /* we can then use this table to provide a table that relates tags to articles */  CREATE TABLE TagTitle   (TagTitle_ID INT IDENTITY(1, 1),   [title_id] [dbo].[tid] NOT NULL REFERENCES titles (Title_ID),   TagName_ID INT NOT NULL REFERENCES TagName (Tagname_ID)   CONSTRAINT [PK_TagTitle]       PRIMARY KEY CLUSTERED ([title_id] ASC, TagName_ID)       ON [PRIMARY])        CREATE NONCLUSTERED INDEX idxTagName_ID  ON  TagTitle (TagName_ID)  INCLUDE (TagTitle_ID,title_id)        /* ...and it is easy to fill this with the tags for each title ... */        INSERT INTO TagTitle (Title_ID, TagName_ID)    SELECT DISTINCT Title_ID, TagName_ID      FROM        (SELECT  Title_ID,          CONVERT(XML, '<list><i>' + REPLACE(TypeList, ',', '</i><i>') + '</i></list>')          AS XMLkeywords          FROM   dbo.titles)g    CROSS APPLY XMLkeywords.nodes('/list/i/text()') AS x ( y )    INNER JOIN TagName ON TagName.Tag=LTRIM(x.y.value('.', 'Varchar(80)'))    END    /* That's all there was to it. Now we can select all titles that have the military tag, just to try things out */SELECT Title FROM titles  INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID  INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE tagname.tag='Military'/* and see the top ten most popular tags for titles */SELECT Tag, COUNT(*) FROM titles  INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID  INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  GROUP BY Tag ORDER BY COUNT(*) DESC/* and if you still want your list of tags for each title, then here they are */SELECT title_ID, title, STUFF(  (SELECT ','+tagname.tag FROM titles thisTitle    INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID    INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE ThisTitle.title_id=titles.title_ID  FOR XML PATH(''), TYPE).value('.', 'varchar(max)')  ,1,1,'')    FROM titles  ORDER BY title_ID So we’ve refactored our PUBS database without pain. We’ve even put in a check to prevent it being re-run once the new tables are created. Here is the diagram of the new tag relationship We’ve done both the DDL to create the tables and their associated components, and the DML to put the data in them. I could have also included the script to remove the de-normalised TypeList column, but I’d do a whole lot of tests first before doing that. Yes, I’ve left out the assertion tests too, which should check the edge cases and make sure the result is what you’d expect. One thing I can’t quite figure out is how to deal with an ordered list using this simple XML-based technique. We can ensure that, if we have to produce a list of tags, we can get the primary ‘type’ to be first in the list, but what if the entire order is significant? Thank goodness it isn’t in this case. If it were, we might have to revisit a string-splitter function that returns the ordinal position of each component in the sequence. You’ll see immediately that we can create a synchronisation script for deployment from a comparison tool such as SQL Compare, to change the schema (DDL). On the other hand, no tool could do the DML to stuff the data into the new table, since there is no way that any tool will be able to work out where the data should go. We used some pretty hairy code to deal with a slightly untypical problem. We would have to do this migration by hand, and it has to go into source control as a batch. If most of your database changes are to be deployed by an automated process, then there must be a way of over-riding this part of the data synchronisation process to do this part of the process taking the part of the script that fills the tables, Checking that the tables have not already been filled, and executing it as part of the transaction. Of course, you might prefer the approach I’ve taken with the script of creating the tables in the same batch as the data conversion process, and then using the presence of the tables to prevent the script from being re-run. The problem with scripting a refactoring change to a database is that it has to work both ways. If we install the new system and then have to rollback the changes, several books may have been added, or had their tags changed, in the meantime. Yes, you have to script any rollback! These have to be mercilessly tested, and put in source control just in case of the rollback of a deployment after it has been in place for any length of time. I’ve shown you how to do this with the part of the script .. /* and if you still want your list of tags for each title, then here they are */SELECT title_ID, title, STUFF(  (SELECT ','+tagname.tag FROM titles thisTitle    INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID    INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE ThisTitle.title_id=titles.title_ID  FOR XML PATH(''), TYPE).value('.', 'varchar(max)')  ,1,1,'')    FROM titles  ORDER BY title_ID …which would be turned into an UPDATE … FROM script. UPDATE titles SET  typelist= ThisTaglistFROM     (SELECT title_ID, title, STUFF(    (SELECT ','+tagname.tag FROM titles thisTitle      INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID      INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID    WHERE ThisTitle.title_id=titles.title_ID    ORDER BY CASE WHEN tagname.tag=titles.[type] THEN 1 ELSE 0  END DESC    FOR XML PATH(''), TYPE).value('.', 'varchar(max)')    ,1,1,'')  AS ThisTagList  FROM titles)fINNER JOIN Titles ON f.title_ID=Titles.title_ID You’ll notice that it isn’t quite a round trip because the tags are in a different order, though we’ve managed to make sure that the primary tag is the first one as originally. So, we’ve improved the database for the poor book distributors using PUBS. It is not a major deal but you’ve got to be prepared to provide a migration script that will go both forwards and backwards. Ideally, database refactoring scripts should be able to go from any version to any other. Schema synchronization scripts can do this pretty easily, but no data synchronisation scripts can deal with serious refactoring jobs without the developers being able to specify how to deal with cases like this.

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• Android From Local DB (DAO) to Server sync (JSON) - Design issue

  - by Taiko

  I sync data between my local DB and a Server. I'm looking for the cleanest way to modelise all of this. I have a com.something.db package That contains a Data Helper and couple of DAO classes that represents objects stored in the db (I didn't write that part) com.something.db --public DataHelper --public Employee @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary etc... (all in all 50 fields) I have a com.something.sync package That contains all the implementation detail on how to send data to the server. It boils down to a ConnectionManager that is fed by different classes that implements a 'Request' interface com.something.sync --public interface ConnectionManager --package ConnectionManagerImpl --public interface Request --package LoginRequest --package GetEmployeesRequest My issue is, at some point in the sync process, I have to JSONise and de-JSONise my data (E.g. the Employee class). But I really don't feel like having the same Employee class be responsible for both his JSONisation and his actual representation inside the local database. It really doesn't feel right, because I carefully decoupled the rest, I am only stuck on this JSON thing. What should I do ? Should I write 3 Employee classes ? EmployeeDB @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary -etc... 50 fields EmployeeInterface -getName -getSalary -etc... 50 fields EmployeeJSON -JSON_KEY_NAME = "name" The JSON key happens to be the same as the table name, but it isn't requirement -name -JSON_KEY_SALARY = "salary" -salary -etc... 50 fields It feels like a lot of duplicates. Is there a common pattern I can use there ?

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• Implementing new required feature after software release

  - by TiagoBrenck

  Fake Scenario There is a software that was released 1 year ago. The software is to map and register all kind of animals on our planet. When the software was released, the client only needed to know the scientific name of the animal, a flag if it is in risk of extinction and a scale of dangerous(that is a fake software and specification, I don't want to discuss this here). There are already 100.000 animals records saved on DB. New Feature One year later, the client wants a new feature. It is really important to him to know the animals classes, and this is a required field. So he asks me to put a field to input the animal class, and this field is required. Or maybe where this animal was discovered. Problem I have already 100.000 recorded animals without a class or where it was discovered, but I need to insert a new column to storage this information and this column can't be null. I don't have a default value for this situation (there isn't a default animal class or where it was discovered). I don't want to keep the requirement rule only on my software, my DB must have this requirement too(I like to keep business rules on DB too). What are the alternatives to solve this situation? I am on a situation that this new feature cannot be previewed or reviewed for the existing records. The time already passed and I can't go back on time to get it

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• Dreaded SQLs

  - by lavanyadeepak

  Dreaded SQLs We used to think that a SQL statement without a where clause is only dangerous right since running that on a server TSQL is just going to impact the entire table like waving the magic wand. For that reason we should cultivate the habit first to write the statement as select and then to modify the select portion as update. Within the T-SQL Window, I would normally prefer the following first: select * from employee where empid in (4,5) and then once I am satisfied with the results, I would go ahead with the following change: --select * delete from employee where empid in (4,5) Today I just discovered another coding horror. This would typically be applicable in a stored procedure and with respect to variable nomenclature. It is always desirable to have a suitable nomenclature for parameters distinct from the column names and internal variables. This would help quicker debugging of the stored procedures besides enhancing the readability. Else in a quick bout of enthusiasm a statement like   if (@CustomerID = @CustomerID) [when the latter is intended to denote the column name and there is a superflous @ prepended], zeroing in on the problem would be little tricky. Had there been a still powerful nomenclature rules then debugging would have been more straight-forward and simpler right?

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• How to handle monetary values in PHP and MySql?

  - by Songo

  I've inherited a huge pile of legacy code written in PHP on top of a MySQL database. The thing I noticed is that the application uses doubles for storage and manipulation of data. Now I came across of numerous posts mentioning how double are not suited for monetary operations because of the rounding errors. However, I have yet to come across a complete solution to how monetary values should be handled in PHP code and stored in a MySQL database. Is there a best practice when it comes to handling money specifically in PHP? Things I'm looking for are: How should the data be stored in the database? column type? size? How should the data be handling in normal addition, subtraction. multiplication or division? When should I round the values? How much rounding is acceptable if any? Is there a difference between handling large monetary values and low ones? Note: A VERY simplified sample code of how I might encounter money values in everyday life: $a= $_POST['price_in_dollars']; //-->(ex: 25.06) will be read as a string should it be cast to double? $b= $_POST['discount_rate'];//-->(ex: 0.35) value will always be less than 1 $valueToBeStored= $a * $b; //--> any hint here is welcomed $valueFromDatabase= $row['price']; //--> price column in database could be double, decimal,...etc. $priceToPrint=$valueFromDatabase * 0.25; //again cast needed or not? I hope you use this sample code as a means to bring out more use cases and not to take it literally of course. Bonus Question If I'm to use an ORM such as Doctrine or PROPEL, how different will it be to use money in my code.

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• TFS SQL Deployment Data Script

  - by Greg

  We are using TFS and SQL 2005 (looking to upgrade to SQL 2012 if that makes a difference). We store our database schema in a Visual Studio Database project (VS 2010). When code is released to live we currently use the Visual Studio Database Project to build a script for all our schema changes. The problem we have been getting is having to alter or add to that script to add/fix data for the deployment. For example if we add a new non-nullable column to an existing table we need to populate that column with data during the insert. Other times we may want to create new records in transactional tables (e.g. assign specific users to a new security access). Do Visual Studio Database Projects have a way to store these scripts that only need to be run once and somehow include them in the build? Does it know which scripts need to be run (for example if we are inserting default data we don't want to do that again a second time)? OR Is there a better way to manage these scripts?

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• PyGTK/Quickly Add string to ListStore

  - by AllRadioisDead

  I'm trying to build an application that will prompt the user for a string, and then add that string to a Scrolling Listview object using quickly and PyGTK. I've been following this tutorial: http://developer.ubuntu.com/resources/app-developer-cookbook/multimedia/creating-a-simple-media-player/ When I hit the add button, the prompt comes up properly and I'm able to enter the string. The column appears correctly but the list ends up being blank. What am I doing wrong? import gettext from gettext import gettext as _ gettext.textdomain('spiderweb') from gi.repository import Gtk # pylint: disable=E0611 import logging logger = logging.getLogger('spiderweb') from spiderweb_lib import Window from spiderweb.AboutSpiderwebDialog import AboutSpiderwebDialog from spiderweb.PreferencesSpiderwebDialog import PreferencesSpiderwebDialog from quickly import prompts from quickly.widgets.dictionary_grid import DictionaryGrid import os # See spiderweb_lib.Window.py for more details about how this class works class SpiderwebWindow(Window): __gtype_name__ = "SpiderwebWindow" def finish_initializing(self, builder): # pylint: disable=E1002 """Set up the main window""" super(SpiderwebWindow, self).finish_initializing(builder) self.AboutDialog = AboutSpiderwebDialog self.PreferencesDialog = PreferencesSpiderwebDialog # Code for other initialization actions should be added here. self.supported_web_formats = [".net",".html", ".com"] def on_addbutton_clicked(self, widget, data=None): #let the user choose a path with the directory chooser response, string = prompts.string("Enter a string", "Please enter string:", "Sample Text") #make certain the user said ok before working if response == Gtk.ResponseType.OK: #make a list of the supported media files media_files = Gtk.ListStore(str) #add a dictionary to the list of media files media_files.append({"String":string}) #remove any children in scrolled window for c in self.ui.scrolledwindow1.get_children(): self.ui.scrolledwindow1.remove(c) #create the grid with list of dictionaries #only show the File column media_grid = DictionaryGrid(media_files, keys=["File"]) #show the grid, and add it to the scrolled window media_grid.show_all() self.ui.scrolledwindow1.add(media_grid)

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