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  • Rails: How to name and create unique divs within a loop?

    - by sscirrus
    I have a view with a div that is looped many times. Each of the created divs need to have a unique ID so I can access them specifically (at the moment, all my divs have the same ID specified in html so whenever I try to access a specific div it just finds the first one). This is the version that I currently have (multiple 'rowBox'es are not discernible). <% @customers.each do |customer| %> <div id="customer" class="rowBox"> ... </div> <% end %> I would like to be able to do something like: <% @customers.each do |customer| %> <div id="box<%=customer.id%>"> ... </div> <% end %> This doesn't seem to work. Any ideas on how to accomplish this?

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  • C# Method not returning a unique value when it should be.

    - by Josh King
    I have two methods, generateNounPhrase() and generateVerbPhrase(). VerbPhrase will call on NounPhrase half the time and it's output the output should be something to the effect of: the empty lot re-animates this pyramid (bold indicating where generateNounPhrase() is logically called). The true output however is in the form of: the empty lot re-animates the empty lot At first I thought my randomIndex method wasn't working as I had intended, but if I run the two methods again I do get different noun phrases but they are not unique at the beginning and end of the sentence as they should be. Any idea what I am doing wrong in order to get one method to show the same result? private string generateNounPhrase() { string nounPhraseString = ""; nounPhraseString = nounMarkersStringList[randomIndex(0,nounMarkersStringList.Count-1)]; if (included(1, 4, 2) == true) { nounPhraseString += " " + adjectivesStringList[randomIndex(0, adjectivesStringList.Count - 1)]; } nounPhraseString += " " + nounsStringList[randomIndex(0, nounsStringList.Count - 1)]; return nounPhraseString; } private string generateVerbPhrase() { string verbPhraseString = ""; if (included(1, 4, 2) == true) { verbPhraseString = intransitiveVerbsStringList[randomIndex(0, intransitiveVerbsStringList.Count - 1)]; } else { verbPhraseString = transitiveVerbsStringList[randomIndex(0, transitiveVerbsStringList.Count - 1)] + " " + generateNounPhrase(); } return verbPhraseString; }

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  • Querying for a unique value based on the aggregate of another value while grouping on a third value

    - by Justin Swartsel
    So I know this problem isn't a new one, but I'm trying to wrap my head around it and understand the best way to deal with scenarios like this. Say I have a hypothetical table 'X' that looks like this: GroupID ID (identity) SomeDateTime -------------------------------------------- 1 1000 1/1/01 1 1001 2/2/02 1 1002 3/3/03 2 1003 4/4/04 2 1004 5/5/05 I want to query it so the result set looks like this: ---------------------------------------- 1 1002 3/3/03 2 1004 5/5/05 Basically what I want is the MAX SomeDateTime value grouped by my GroupID column. The kicker is that I DON'T want to group by the ID column, I just want to know the 'ID' that corresponds to the MAX SomeDateTime. I know one pseudo-solution would be: ;WITH X1 as ( SELECT MAX(SomeDateTime) as SomeDateTime, GroupID FROM X GROUP BY GroupID ) SELECT X1.SomeDateTime, X1.GroupID, X2.ID FROM X1 INNER JOIN X as X2 ON X.DateTime = X2.DateTime But this doesn't solve the fact that a DateTime might not be unique. And it seems sloppy to join on a DateTime like that. Another pseudo-solution could be: SELECT X.GroupID, MAX(X.ID) as ID, MAX(X.SomeDateTime) as SomeDateTime FROM X GROUP BY X.GroupID But there are no guarantees that ID will actually match the row that SomeDateTime comes from. A third less useful option might be: SELECT TOP 1 X.GroupID, X.ID, X.SomeDateTime FROM X WHERE X.GroupID = 1 ORDER BY X.SomeDateTime DESC But obviously that only works with a single, known, GroupID. I want to be able to join this result set on GroupID and/or ID. Does anyone know of any clever solutions? Any good uses of windowing functions? Thanks!

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  • PHP - How do you secure a unique variable name?

    - by 102319141763223461745
    This function cropit, which I shamelessly stole off the internet, crops a 90x60 area from an existing image. In this code, when I use the function for more than one item (image) the one will display on top of the other (they come to occupy the same output space). I think this is because the function has the same (static) name ($dest) for the destination of the image when it's created (imagecopy). I tried, as you can see to include a second argument to the cropit function which would serve as the "name" of the $dest variable, but it didn't work. In the interest of full disclosure I have 22 hours of PHP experience (incidentally the same number of hours since the last I slept) and I am not that smart to begin with. Even if there's something else at work here entirely, seems to me that generally it must be useful to have a way to secure that a variable is always given a unique name. function cropit($srcimg, $dest) { $im = imagecreatefromjpeg($srcimg); $img_width = imagesx($im); $img_height = imagesy($im); $width = 90; $height = 60; $tlx = floor($img_width / 2) - floor ($width / 2); $tly = floor($img_height / 2) - floor ($height / 2); if ($tlx < 0) { $tlx = 0; } if ($tly < 0) { $tly = 0; } if (($img_width - $tlx) < $width) { $width = $img_width - $tlx; } if (($img_height - $tly) < $height) { $height = $img_height - $tly; } $dest = imagecreatetruecolor ($width, $height); imagecopy($dest, $im, 0, 0, $tlx, $tly, $width, $height); imagejpeg($dest); imagedestroy($dest); } $img = "imagefolder\imageone.jpg"; $img2 = "imagefolder\imagetwo.jpg"; cropit($img, $i1); cropit($img2, $i2); ?

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  • Is it possible to get a truly unique id for a particular JVM instance?

    - by Uri
    I need a way to uniquely and permanently identify an instance of the JVM from within Java code running in that JVM. That is, if I have two JVMs running at the same time on the same machine, each is distinguishable. It is also distinguishable from running JVMs on other machines and from future executions on the same machine even if the process id is reused. I figure I could implement something like this by identifying the start time, the machine MAC, and the process id, and combining them in some way. I'm wondering if there is some standard way to achieve this. Update: I see that everyone recommended a UUID for the entire session. That seems like a good idea though possibly a little too heavyweight. Here is my problem though: I want to use the JVM id to create multiple unique identifiers in each JVM execution that somehow incorporate the JVM instance. My understanding is that you shouldn't really mix other numbers into a UUID because uniqueness is no longer guaranteed. An alternative is to make the UUID into a string and chain it, but then it becomes too long. Any ideas on overcoming this?

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  • Data model for timesheet to task and/or timesheet to project?

    - by John
    Let's say I want to make a simple project tracking system. A manager can create a project. Then he can create tasks for that project. Team members can record the hours they work for each task or for the project as a whole. Is the following design for the t_timesheet table a good idea? timesheet_id - primary key, autoincrement project_id - not null, foreign key constraint to t_project task_id - nullable, foreign key constraint to t_task user_id - not null, foreign key constraint to t_user hours - decimal Or should I do something like this: timesheet_id - primary key, autoincrement task_id - not null, foreign key constraint to t_task user_id - not null, foreign key constraint to t_user hours - decimal In the second option, I intend to always have a record in t_task labelled "miscellaneous items" with a foreign key to the relevant t_project record. Then I'll be able to track all hours for a project that aren't for any particular task. Are any of the ideas above good? What would be better?

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  • How can I remove rows with unique values? As in only keeping rows with duplicate values?

    - by user1456405
    Here's the conundrum, I'm a complete and utter noob when it comes to programming. I understand the basics, but am still learning javascript. I have a spreadsheet of surveys, in which I need to see how particular users have varied over time. As such, I need to disregard all rows with unique values in a particular column. The data looks like this: Response Date Response_ID Account_ID Q.1 10/20/2011 12:03:43 PM 23655956 1168161 8 10/20/2011 03:52:57 PM 23660161 1168152 0 10/21/2011 10:55:54 AM 23672903 1166121 7 10/23/2011 04:28:16 PM 23694471 1144756 9 10/25/2011 06:30:52 AM 23732674 1167449 7 10/25/2011 07:52:28 AM 23734597 1087618 5 I've found a way to do so in VBA, which sucks as I have to use excel, per below: Sub Del_Unique() Application.ScreenUpdating = False Columns("B:B").Insert Shift:=xlToRight Columns("A:A").Copy Destination:=Columns("B:B") i = Application.CountIf(Range("A:A"), "<>") + 50 If i > 65536 Then i = 65536 Do If Application.CountIf(Range("B:B"), Range("A" & i)) = 1 Then Rows(i).Delete End If i = i - 1 Loop Until i = 0 Columns("B:B").Delete Application.ScreenUpdating = True End Sub But that requires mucking about. I'd really like to do it in Google Spreadsheets with a script that won't have to be changed. Closest I can get is retrieving all duplicate user ids from the range, but can't associate that with the row. That code follows: function findDuplicatesInSelection() { var activeRange = SpreadsheetApp.getActiveRange(); var values = activeRange.getValues(); // values that appear at least once var once = {}; // values that appear at least twice var twice = {}; // values that appear at least twice, stored in a pretty fashion! var final = []; for (var i = 0; i < values.length; i++) { var inner = values[i]; for (var j = 0; j < inner.length; j++) { var cell = inner[j]; if (cell == "") continue; if (once.hasOwnProperty(cell)) { if (!twice.hasOwnProperty(cell)) { final.push(cell); } twice[cell] = 1; } else { once[cell] = 1; } } } if (final.length == 0) { Browser.msgBox("No duplicates found"); } else { Browser.msgBox("Duplicates are: " + final); } } Anyhow, sorry if this is the wrong place or format, but half of what I've found so far has been from stack, I thought it was a good place to start. Thanks!

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  • How to use XSLT to tag specific nodes with unique, sequential, increasing integer ids?

    - by ~otakuj462
    Hi, I'm trying to use XSLT to transform a document by tagging a group of XML nodes with integer ids, starting at 0, and increasing by one for each node in the group. The XML passed into the stylesheet should be echoed out, but augmented to include this extra information. Just to be clear about what I am talking about, here is how this transformation would be expressed using DOM: states = document.getElementsByTagName("state"); for( i = 0; i < states.length; i++){ states.stateNum = i; } This is very simple with DOM, but I'm having much more trouble doing this with XSLT. The current strategy I've devised has been to start with the identity transformation, then create a global variable which selects and stores all of the nodes that I wish to number. I then create a template that matches that kind of node. The idea, then, is that in the template, I would look up the matched node's position in the global variable nodelist, which would give me a unique number that I could then set as an attribute. The problem with this approach is that the position function can only be used with the context node, so something like the following is illegal: <template match="state"> <variable name="stateId" select="@id"/> <variable name="uniqueStateNum" select="$globalVariable[@id = $stateId]/position()"/> </template> The same is true for the following: <template match="state"> <variable name="stateId" select="@id" <variable name="stateNum" select="position($globalVariable[@id = $stateId])/"/> </template> In order to use position() to look up the position of an element in $globalVariable, the context node must be changed. I have found a solution, but it is highly suboptimal. Basically, in the template, I use for-each to iterate through the global variable. For-each changes the context node, so this allows me to use position() in the way I described. The problem is that this turns what would normally be an O(n) operation into an O(n^2) operation, where n is the length of the nodelist, as this require iterating through the whole list whenever the template is matched. I think that there must be a more elegant solution. Altogether, here is my current (slightly simplified) xslt stylesheet: <?xml version="1.0"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:s="http://www.w3.org/2005/07/scxml" xmlns="http://www.w3.org/2005/07/scxml" xmlns:c="http://msdl.cs.mcgill.ca/" version="1.0"> <xsl:output method="xml"/> <!-- we copy them, so that we can use their positions as identifiers --> <xsl:variable name="states" select="//s:state" /> <!-- identity transform --> <xsl:template match="@*|node()"> <xsl:copy> <xsl:apply-templates select="@*|node()"/> </xsl:copy> </xsl:template> <xsl:template match="s:state"> <xsl:variable name="stateId"> <xsl:value-of select="@id"/> </xsl:variable> <xsl:copy> <xsl:apply-templates select="@*"/> <xsl:for-each select="$states"> <xsl:if test="@id = $stateId"> <xsl:attribute name="stateNum" namespace="http://msdl.cs.mcgill.ca/"> <xsl:value-of select="position()"/> </xsl:attribute> </xsl:if> </xsl:for-each> <xsl:apply-templates select="node()"/> </xsl:copy> </xsl:template> </xsl:stylesheet> I'd appreciate any advice anyone can offer. Thanks.

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  • Seeking on a Heap, and Two Useful DMVs

    - by Paul White
    So far in this mini-series on seeks and scans, we have seen that a simple ‘seek’ operation can be much more complex than it first appears.  A seek can contain one or more seek predicates – each of which can either identify at most one row in a unique index (a singleton lookup) or a range of values (a range scan).  When looking at a query plan, we will often need to look at the details of the seek operator in the Properties window to see how many operations it is performing, and what type of operation each one is.  As you saw in the first post in this series, the number of hidden seeking operations can have an appreciable impact on performance. Measuring Seeks and Scans I mentioned in my last post that there is no way to tell from a graphical query plan whether you are seeing a singleton lookup or a range scan.  You can work it out – if you happen to know that the index is defined as unique and the seek predicate is an equality comparison, but there’s no separate property that says ‘singleton lookup’ or ‘range scan’.  This is a shame, and if I had my way, the query plan would show different icons for range scans and singleton lookups – perhaps also indicating whether the operation was one or more of those operations underneath the covers. In light of all that, you might be wondering if there is another way to measure how many seeks of either type are occurring in your system, or for a particular query.  As is often the case, the answer is yes – we can use a couple of dynamic management views (DMVs): sys.dm_db_index_usage_stats and sys.dm_db_index_operational_stats. Index Usage Stats The index usage stats DMV contains counts of index operations from the perspective of the Query Executor (QE) – the SQL Server component that is responsible for executing the query plan.  It has three columns that are of particular interest to us: user_seeks – the number of times an Index Seek operator appears in an executed plan user_scans – the number of times a Table Scan or Index Scan operator appears in an executed plan user_lookups – the number of times an RID or Key Lookup operator appears in an executed plan An operator is counted once per execution (generating an estimated plan does not affect the totals), so an Index Seek that executes 10,000 times in a single plan execution adds 1 to the count of user seeks.  Even less intuitively, an operator is also counted once per execution even if it is not executed at all.  I will show you a demonstration of each of these things later in this post. Index Operational Stats The index operational stats DMV contains counts of index and table operations from the perspective of the Storage Engine (SE).  It contains a wealth of interesting information, but the two columns of interest to us right now are: range_scan_count – the number of range scans (including unrestricted full scans) on a heap or index structure singleton_lookup_count – the number of singleton lookups in a heap or index structure This DMV counts each SE operation, so 10,000 singleton lookups will add 10,000 to the singleton lookup count column, and a table scan that is executed 5 times will add 5 to the range scan count. The Test Rig To explore the behaviour of seeks and scans in detail, we will need to create a test environment.  The scripts presented here are best run on SQL Server 2008 Developer Edition, but the majority of the tests will work just fine on SQL Server 2005.  A couple of tests use partitioning, but these will be skipped if you are not running an Enterprise-equivalent SKU.  Ok, first up we need a database: USE master; GO IF DB_ID('ScansAndSeeks') IS NOT NULL DROP DATABASE ScansAndSeeks; GO CREATE DATABASE ScansAndSeeks; GO USE ScansAndSeeks; GO ALTER DATABASE ScansAndSeeks SET ALLOW_SNAPSHOT_ISOLATION OFF ; ALTER DATABASE ScansAndSeeks SET AUTO_CLOSE OFF, AUTO_SHRINK OFF, AUTO_CREATE_STATISTICS OFF, AUTO_UPDATE_STATISTICS OFF, PARAMETERIZATION SIMPLE, READ_COMMITTED_SNAPSHOT OFF, RESTRICTED_USER ; Notice that several database options are set in particular ways to ensure we get meaningful and reproducible results from the DMVs.  In particular, the options to auto-create and update statistics are disabled.  There are also three stored procedures, the first of which creates a test table (which may or may not be partitioned).  The table is pretty much the same one we used yesterday: The table has 100 rows, and both the key_col and data columns contain the same values – the integers from 1 to 100 inclusive.  The table is a heap, with a non-clustered primary key on key_col, and a non-clustered non-unique index on the data column.  The only reason I have used a heap here, rather than a clustered table, is so I can demonstrate a seek on a heap later on.  The table has an extra column (not shown because I am too lazy to update the diagram from yesterday) called padding – a CHAR(100) column that just contains 100 spaces in every row.  It’s just there to discourage SQL Server from choosing table scan over an index + RID lookup in one of the tests. The first stored procedure is called ResetTest: CREATE PROCEDURE dbo.ResetTest @Partitioned BIT = 'false' AS BEGIN SET NOCOUNT ON ; IF OBJECT_ID(N'dbo.Example', N'U') IS NOT NULL BEGIN DROP TABLE dbo.Example; END ; -- Test table is a heap -- Non-clustered primary key on 'key_col' CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, padding CHAR(100) NOT NULL DEFAULT SPACE(100), CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ; IF @Partitioned = 'true' BEGIN -- Enterprise, Trial, or Developer -- required for partitioning tests IF SERVERPROPERTY('EngineEdition') = 3 BEGIN EXECUTE (' DROP TABLE dbo.Example ; IF EXISTS ( SELECT 1 FROM sys.partition_schemes WHERE name = N''PS'' ) DROP PARTITION SCHEME PS ; IF EXISTS ( SELECT 1 FROM sys.partition_functions WHERE name = N''PF'' ) DROP PARTITION FUNCTION PF ; CREATE PARTITION FUNCTION PF (INTEGER) AS RANGE RIGHT FOR VALUES (20, 40, 60, 80, 100) ; CREATE PARTITION SCHEME PS AS PARTITION PF ALL TO ([PRIMARY]) ; CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, padding CHAR(100) NOT NULL DEFAULT SPACE(100), CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ON PS (key_col); '); END ELSE BEGIN RAISERROR('Invalid SKU for partition test', 16, 1); RETURN; END; END ; -- Non-unique non-clustered index on the 'data' column CREATE NONCLUSTERED INDEX [IX dbo.Example data] ON dbo.Example (data) ; -- Add 100 rows INSERT dbo.Example WITH (TABLOCKX) ( key_col, data ) SELECT key_col = V.number, data = V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 100 ; END; GO The second stored procedure, ShowStats, displays information from the Index Usage Stats and Index Operational Stats DMVs: CREATE PROCEDURE dbo.ShowStats @Partitioned BIT = 'false' AS BEGIN -- Index Usage Stats DMV (QE) SELECT index_name = ISNULL(I.name, I.type_desc), scans = IUS.user_scans, seeks = IUS.user_seeks, lookups = IUS.user_lookups FROM sys.dm_db_index_usage_stats AS IUS JOIN sys.indexes AS I ON I.object_id = IUS.object_id AND I.index_id = IUS.index_id WHERE IUS.database_id = DB_ID(N'ScansAndSeeks') AND IUS.object_id = OBJECT_ID(N'dbo.Example', N'U') ORDER BY I.index_id ; -- Index Operational Stats DMV (SE) IF @Partitioned = 'true' SELECT index_name = ISNULL(I.name, I.type_desc), partitions = COUNT(IOS.partition_number), range_scans = SUM(IOS.range_scan_count), single_lookups = SUM(IOS.singleton_lookup_count) FROM sys.dm_db_index_operational_stats ( DB_ID(N'ScansAndSeeks'), OBJECT_ID(N'dbo.Example', N'U'), NULL, NULL ) AS IOS JOIN sys.indexes AS I ON I.object_id = IOS.object_id AND I.index_id = IOS.index_id GROUP BY I.index_id, -- Key I.name, I.type_desc ORDER BY I.index_id; ELSE SELECT index_name = ISNULL(I.name, I.type_desc), range_scans = SUM(IOS.range_scan_count), single_lookups = SUM(IOS.singleton_lookup_count) FROM sys.dm_db_index_operational_stats ( DB_ID(N'ScansAndSeeks'), OBJECT_ID(N'dbo.Example', N'U'), NULL, NULL ) AS IOS JOIN sys.indexes AS I ON I.object_id = IOS.object_id AND I.index_id = IOS.index_id GROUP BY I.index_id, -- Key I.name, I.type_desc ORDER BY I.index_id; END; The final stored procedure, RunTest, executes a query written against the example table: CREATE PROCEDURE dbo.RunTest @SQL VARCHAR(8000), @Partitioned BIT = 'false' AS BEGIN -- No execution plan yet SET STATISTICS XML OFF ; -- Reset the test environment EXECUTE dbo.ResetTest @Partitioned ; -- Previous call will throw an error if a partitioned -- test was requested, but SKU does not support it IF @@ERROR = 0 BEGIN -- IO statistics and plan on SET STATISTICS XML, IO ON ; -- Test statement EXECUTE (@SQL) ; -- Plan and IO statistics off SET STATISTICS XML, IO OFF ; EXECUTE dbo.ShowStats @Partitioned; END; END; The Tests The first test is a simple scan of the heap table: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example'; The top result set comes from the Index Usage Stats DMV, so it is the Query Executor’s (QE) view.  The lower result is from Index Operational Stats, which shows statistics derived from the actions taken by the Storage Engine (SE).  We see that QE performed 1 scan operation on the heap, and SE performed a single range scan.  Let’s try a single-value equality seek on a unique index next: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col = 32'; This time we see a single seek on the non-clustered primary key from QE, and one singleton lookup on the same index by the SE.  Now for a single-value seek on the non-unique non-clustered index: EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data = 32'; QE shows a single seek on the non-clustered non-unique index, but SE shows a single range scan on that index – not the singleton lookup we saw in the previous test.  That makes sense because we know that only a single-value seek into a unique index is a singleton seek.  A single-value seek into a non-unique index might retrieve any number of rows, if you think about it.  The next query is equivalent to the IN list example seen in the first post in this series, but it is written using OR (just for variety, you understand): EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data = 32 OR data = 33'; The plan looks the same, and there’s no difference in the stats recorded by QE, but the SE shows two range scans.  Again, these are range scans because we are looking for two values in the data column, which is covered by a non-unique index.  I’ve added a snippet from the Properties window to show that the query plan does show two seek predicates, not just one.  Now let’s rewrite the query using BETWEEN: EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data BETWEEN 32 AND 33'; Notice the seek operator only has one predicate now – it’s just a single range scan from 32 to 33 in the index – as the SE output shows.  For the next test, we will look up four values in the key_col column: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col IN (2,4,6,8)'; Just a single seek on the PK from the Query Executor, but four singleton lookups reported by the Storage Engine – and four seek predicates in the Properties window.  On to a more complex example: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example WITH (INDEX([PK dbo.Example key_col])) WHERE key_col BETWEEN 1 AND 8'; This time we are forcing use of the non-clustered primary key to return eight rows.  The index is not covering for this query, so the query plan includes an RID lookup into the heap to fetch the data and padding columns.  The QE reports a seek on the PK and a lookup on the heap.  The SE reports a single range scan on the PK (to find key_col values between 1 and 8), and eight singleton lookups on the heap.  Remember that a bookmark lookup (RID or Key) is a seek to a single value in a ‘unique index’ – it finds a row in the heap or cluster from a unique RID or clustering key – so that’s why lookups are always singleton lookups, not range scans. Our next example shows what happens when a query plan operator is not executed at all: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col = 8 AND @@TRANCOUNT < 0'; The Filter has a start-up predicate which is always false (if your @@TRANCOUNT is less than zero, call CSS immediately).  The index seek is never executed, but QE still records a single seek against the PK because the operator appears once in an executed plan.  The SE output shows no activity at all.  This next example is 2008 and above only, I’m afraid: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example WHERE key_col BETWEEN 1 AND 30', @Partitioned = 'true'; This is the first example to use a partitioned table.  QE reports a single seek on the heap (yes – a seek on a heap), and the SE reports two range scans on the heap.  SQL Server knows (from the partitioning definition) that it only needs to look at partitions 1 and 2 to find all the rows where key_col is between 1 and 30 – the engine seeks to find the two partitions, and performs a range scan seek on each partition. The final example for today is another seek on a heap – try to work out the output of the query before running it! EXECUTE dbo.RunTest @SQL = 'SELECT TOP (2) WITH TIES * FROM Example WHERE key_col BETWEEN 1 AND 50 ORDER BY $PARTITION.PF(key_col) DESC', @Partitioned = 'true'; Notice the lack of an explicit Sort operator in the query plan to enforce the ORDER BY clause, and the backward range scan. © 2011 Paul White email: [email protected] twitter: @SQL_Kiwi

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  • Websphere 7 simple realm (like tomcat-users.xml)

    - by Heavy Bytes
    I am trying to port a J2EE app from Tomcat to Websphere and I'm not too familiar with Websphere. The only problem I am having is authorization (I use basic-authentication in my web.xml). In Tomcat I use the tomcat-users.xml file to define my users/passwords and to what roles they belong. How do I do this "simply" in Websphere? When deploying the EAR to Websphere it also asks me to map my role from web.xml to a user or group. Do I have to set up some sort of realm? Custom user registry? Thanks. UPDATE: I configured a Standalone custom registry, however I can't get a log-in prompt for username/password. It works just fine in Tomcat, and it doesn't in Websphere. Code from web.xml <security-constraint> <web-resource-collection> <web-resource-name>basic-auth security</web-resource-name> <url-pattern>/*</url-pattern> </web-resource-collection> <auth-constraint> <role-name>HELLO_USER</role-name> </auth-constraint> <user-data-constraint>NONE</user-data-constraint> </security-constraint> <login-config> <auth-method>BASIC</auth-method> </login-config> <security-role> <role-name>HELLO_USER</role-name> </security-role>

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  • Doctrine 1.2: How do i prevent a contraint from being assigned to both sides of a One-to-many relati

    - by prodigitalson
    Is there a way to prevent Doctrine from assigning a contraint on both sides of a one-to-one relationship? Ive tried moving the definition from one side to the other and using owning side but it still places a constraint on both tables. when I only want the parent table to have a constraint - ie. its possible for the parent to not have an associated child. For example iwant the following sql schema essentially: CREATE TABLE `parent_table` ( `child_id` varchar(50) NOT NULL, `id` integer UNSIGNED NOT NULL auto_increment, PRIMARY KEY (`id`) ); CREATE TABLE `child_table` ( `id` integer UNSIGNED NOT NULL auto_increment, `child_id` varchar(50) NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY (`child_id`), CONSTRAINT `parent_table_child_id_FK_child_table_child_id` FOREIGN KEY (`child_id`) REFERENCES `parent_table` (`child_id`) ); However im getting something like this: CREATE TABLE `parent_table` ( `child_id` varchar(50) NOT NULL, `id` integer UNSIGNED NOT NULL auto_increment, PRIMARY KEY (`id`), CONSTRAINT `child_table_child_id_FK_parent_table_child_id` FOREIGN KEY (`child_id`) REFERENCES `child_table` (`child_id`) ); CREATE TABLE `child_table` ( `id` integer UNSIGNED NOT NULL auto_increment, `child_id` varchar(50) NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY (`child_id`), CONSTRAINT `parent_table_child_id_FK_child_table_child_id` FOREIGN KEY (`child_id`) REFERENCES `parent_table` (`child_id`) ); I could just remove the constraint manually or modify my accessors to return/set a single entity in the collection (using a one-to-many) but it seems like there should built in way to handle this. Also im using Symfony 1.4.4 (pear installtion ATM) - in case its an sfDoctrinePlugin issue and not necessarily Doctrine itself.

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  • Creating a procedure with PLSQL

    - by user1857460
    I am trying to write a PLSQL function that implements a constraint that an employee cannot be both a driver and a mechanic at the same time, in other words, the same E# from TRKEMPLOYEE cannot be in TRKDRIVER and TRKMECHANIC at the same time. The abovementioned tables are something like as follows: TRKEMPLOYEE(E# NUMBER(12) NOT NULL CONSTRAINT TRKEMPLOYEE_PKEY PRIMARY KEY(E#)) TRKDRIVER(E# NUMBER(12) NOT NULL CONSTRAINT TRKDRIVER_PKEY PRIMARY KEY(E#), CONSTRAINT TRKDRIVER_FKEY FOREIGN KEY(E#) REFERENCES TRKEMPLOYEE(E#)) TRKMECHANIC(E# NUMBER(12) NOT NULL CONSTRAINT TRKMECHANIC_PKEY PRIMARY KEY(E#), CONSTRAINT TRKMECHANIC_FKEY FOREIGN KEY(E#) REFERENCES TRKEMPLOYEE(E#)) I have attempted to write a function but keep getting a compile error in line 1 column 7. Can someone tell me why my code doesn't work? My code is as follows CREATE OR REPLACE FUNCTION Verify() IS DECLARE E# TRKEMPLOYEE.E#%TYPE; CURSOR C1 IS SELECT E# FROM TRKEMPLOYEE; BEGIN OPEN C1; LOOP FETCH C1 INTO EMPNUM; IF(EMPNUM IN(SELECT E# FROM TRKMECHANIC )AND EMPNUM IN(SELECT E# FROM TRKDRIVER)) SELECT E#, NAME FROM TRKEMPLOYEE WHERE E#=EMPNUM; ELSE dbms_output.put_line(“OK”); ENDIF EXIT WHEN C1%NOTFOUND; END LOOP; CLOSE C1; END; / Any help would be appreciated. Thanks.

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  • Convert VARCHAR() columns to NVARCHAR()

    - by ChrisD
    We recently underwent an upgrade that required us to change our database columns from varchar to NVarchar, to support unicode characters. Digging through the internet, I found a base script which I modified to handle reserved word table names, and maintain the NULL/NotNull constraint of the columns.   I Ran this script use NWOperationalContent – Your Catalog Name here GO SELECT 'ALTER TABLE ' + isnull(schema_name(syo.id), 'dbo') + '.[' +  syo.name +'] '     + ' ALTER COLUMN [' + syc.name + '] NVARCHAR(' + case syc.length when -1 then 'MAX'         ELSE convert(nvarchar(10),syc.length) end + ') '+         case  syc.isnullable when 1 then ' NULL' ELSE ' NOT NULL' END +';'    FROM sysobjects syo    JOIN syscolumns syc ON      syc.id = syo.id    JOIN systypes syt ON      syt.xtype = syc.xtype    WHERE      syt.name = 'varchar'     and syo.xtype='U'   which produced a series of ALTER statements which I could then execute the tables.  In some cases I had to drop indexes, alter the tables, and re-create the indexes.  There might have been a better way to do that, but manually dropping them got the job done.   use NWMerchandisingContent GO ALTER TABLE Locale Drop Constraint PK_Locale ALTER TABLE Country DROP CONSTRAINT PK_Country GO ALTER TABLE dbo.[Campaign]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[BundleLocalization]  ALTER COLUMN [Locale] NVARCHAR(8)  NOT NULL; ALTER TABLE dbo.[BundleLocalization]  ALTER COLUMN [UnitOfmeasure] NVARCHAR(200)  NULL; ALTER TABLE dbo.[BundleLocalization]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [Locale] NVARCHAR(8)  NOT NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [Imperative] NVARCHAR(MAX)  NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [Instructions] NVARCHAR(MAX)  NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[BundleComponent]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Bundle]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Banner]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Video]  ALTER COLUMN [Link] NVARCHAR(512)  NOT NULL; ALTER TABLE dbo.[Video]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[ProductUsage]  ALTER COLUMN [VideoLink] NVARCHAR(512)  NOT NULL; ALTER TABLE dbo.[ProductUsage]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Thumbnail]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[SkuLocalization]  ALTER COLUMN [Locale] NVARCHAR(8)  NOT NULL; ALTER TABLE dbo.[SkuLocalization]  ALTER COLUMN [UnitOfMeasure] NVARCHAR(150)  NOT NULL; ALTER TABLE dbo.[SkuLocalization]  ALTER COLUMN [SwatchColor] NVARCHAR(50)  NOT NULL; etc.. GO ALTER TABLE Locale ADD CONSTRAINT PK_Locale PRIMARY KEY (LocaleId) ALTER TABLE Country ADD CONSTRAINT PK_Country PRIMARY KEY (CountryId) Note that this alter is non-destructive to the data.   Hope this helps.

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  • Operator of the week - Assert

    - by Fabiano Amorim
    Well my friends, I was wondering how to help you in a practical way to understand execution plans. So I think I'll talk about the Showplan Operators. Showplan Operators are used by the Query Optimizer (QO) to build the query plan in order to perform a specified operation. A query plan will consist of many physical operators. The Query Optimizer uses a simple language that represents each physical operation by an operator, and each operator is represented in the graphical execution plan by an icon. I'll try to talk about one operator every week, but so as to avoid having to continue to write about these operators for years, I'll mention only of those that are more common: The first being the Assert. The Assert is used to verify a certain condition, it validates a Constraint on every row to ensure that the condition was met. If, for example, our DDL includes a check constraint which specifies only two valid values for a column, the Assert will, for every row, validate the value passed to the column to ensure that input is consistent with the check constraint. Assert  and Check Constraints: Let's see where the SQL Server uses that information in practice. Take the following T-SQL: IF OBJECT_ID('Tab1') IS NOT NULL   DROP TABLE Tab1 GO CREATE TABLE Tab1(ID Integer, Gender CHAR(1))  GO  ALTER TABLE TAB1 ADD CONSTRAINT ck_Gender_M_F CHECK(Gender IN('M','F'))  GO INSERT INTO Tab1(ID, Gender) VALUES(1,'X') GO To the command above the SQL Server has generated the following execution plan: As we can see, the execution plan uses the Assert operator to check that the inserted value doesn't violate the Check Constraint. In this specific case, the Assert applies the rule, 'if the value is different to "F" and different to "M" than return 0 otherwise returns NULL'. The Assert operator is programmed to show an error if the returned value is not NULL; in other words, the returned value is not a "M" or "F". Assert checking Foreign Keys Now let's take a look at an example where the Assert is used to validate a foreign key constraint. Suppose we have this  query: ALTER TABLE Tab1 ADD ID_Genders INT GO  IF OBJECT_ID('Tab2') IS NOT NULL   DROP TABLE Tab2 GO CREATE TABLE Tab2(ID Integer PRIMARY KEY, Gender CHAR(1))  GO  INSERT INTO Tab2(ID, Gender) VALUES(1, 'F') INSERT INTO Tab2(ID, Gender) VALUES(2, 'M') INSERT INTO Tab2(ID, Gender) VALUES(3, 'N') GO  ALTER TABLE Tab1 ADD CONSTRAINT fk_Tab2 FOREIGN KEY (ID_Genders) REFERENCES Tab2(ID) GO  INSERT INTO Tab1(ID, ID_Genders, Gender) VALUES(1, 4, 'X') Let's look at the text execution plan to see what these Assert operators were doing. To see the text execution plan just execute SET SHOWPLAN_TEXT ON before run the insert command. |--Assert(WHERE:(CASE WHEN NOT [Pass1008] AND [Expr1007] IS NULL THEN (0) ELSE NULL END))      |--Nested Loops(Left Semi Join, PASSTHRU:([Tab1].[ID_Genders] IS NULL), OUTER REFERENCES:([Tab1].[ID_Genders]), DEFINE:([Expr1007] = [PROBE VALUE]))           |--Assert(WHERE:(CASE WHEN [Tab1].[Gender]<>'F' AND [Tab1].[Gender]<>'M' THEN (0) ELSE NULL END))           |    |--Clustered Index Insert(OBJECT:([Tab1].[PK]), SET:([Tab1].[ID] = RaiseIfNullInsert([@1]),[Tab1].[ID_Genders] = [@2],[Tab1].[Gender] = [Expr1003]), DEFINE:([Expr1003]=CONVERT_IMPLICIT(char(1),[@3],0)))           |--Clustered Index Seek(OBJECT:([Tab2].[PK]), SEEK:([Tab2].[ID]=[Tab1].[ID_Genders]) ORDERED FORWARD) Here we can see the Assert operator twice, first (looking down to up in the text plan and the right to left in the graphical plan) validating the Check Constraint. The same concept showed above is used, if the exit value is "0" than keep running the query, but if NULL is returned shows an exception. The second Assert is validating the result of the Tab1 and Tab2 join. It is interesting to see the "[Expr1007] IS NULL". To understand that you need to know what this Expr1007 is, look at the Probe Value (green text) in the text plan and you will see that it is the result of the join. If the value passed to the INSERT at the column ID_Gender exists in the table Tab2, then that probe will return the join value; otherwise it will return NULL. So the Assert is checking the value of the search at the Tab2; if the value that is passed to the INSERT is not found  then Assert will show one exception. If the value passed to the column ID_Genders is NULL than the SQL can't show a exception, in that case it returns "0" and keeps running the query. If you run the INSERT above, the SQL will show an exception because of the "X" value, but if you change the "X" to "F" and run again, it will show an exception because of the value "4". If you change the value "4" to NULL, 1, 2 or 3 the insert will be executed without any error. Assert checking a SubQuery: The Assert operator is also used to check one subquery. As we know, one scalar subquery can't validly return more than one value: Sometimes, however, a  mistake happens, and a subquery attempts to return more than one value . Here the Assert comes into play by validating the condition that a scalar subquery returns just one value. Take the following query: INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1), 'F')    INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1), 'F')    |--Assert(WHERE:(CASE WHEN NOT [Pass1016] AND [Expr1015] IS NULL THEN (0) ELSE NULL END))        |--Nested Loops(Left Semi Join, PASSTHRU:([tempdb].[dbo].[Tab1].[ID_TipoSexo] IS NULL), OUTER REFERENCES:([tempdb].[dbo].[Tab1].[ID_TipoSexo]), DEFINE:([Expr1015] = [PROBE VALUE]))              |--Assert(WHERE:([Expr1017]))             |    |--Compute Scalar(DEFINE:([Expr1017]=CASE WHEN [tempdb].[dbo].[Tab1].[Sexo]<>'F' AND [tempdb].[dbo].[Tab1].[Sexo]<>'M' THEN (0) ELSE NULL END))              |         |--Clustered Index Insert(OBJECT:([tempdb].[dbo].[Tab1].[PK__Tab1__3214EC277097A3C8]), SET:([tempdb].[dbo].[Tab1].[ID_TipoSexo] = [Expr1008],[tempdb].[dbo].[Tab1].[Sexo] = [Expr1009],[tempdb].[dbo].[Tab1].[ID] = [Expr1003]))              |              |--Top(TOP EXPRESSION:((1)))              |                   |--Compute Scalar(DEFINE:([Expr1008]=[Expr1014], [Expr1009]='F'))              |                        |--Nested Loops(Left Outer Join)              |                             |--Compute Scalar(DEFINE:([Expr1003]=getidentity((1856985942),(2),NULL)))              |                             |    |--Constant Scan              |                             |--Assert(WHERE:(CASE WHEN [Expr1013]>(1) THEN (0) ELSE NULL END))              |                                  |--Stream Aggregate(DEFINE:([Expr1013]=Count(*), [Expr1014]=ANY([tempdb].[dbo].[Tab1].[ID_TipoSexo])))             |                                       |--Clustered Index Scan(OBJECT:([tempdb].[dbo].[Tab1].[PK__Tab1__3214EC277097A3C8]))              |--Clustered Index Seek(OBJECT:([tempdb].[dbo].[Tab2].[PK__Tab2__3214EC27755C58E5]), SEEK:([tempdb].[dbo].[Tab2].[ID]=[tempdb].[dbo].[Tab1].[ID_TipoSexo]) ORDERED FORWARD)  You can see from this text showplan that SQL Server as generated a Stream Aggregate to count how many rows the SubQuery will return, This value is then passed to the Assert which then does its job by checking its validity. Is very interesting to see that  the Query Optimizer is smart enough be able to avoid using assert operators when they are not necessary. For instance: INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1 WHERE ID = 1), 'F') INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT TOP 1 ID_TipoSexo FROM Tab1), 'F')  For both these INSERTs, the Query Optimiser is smart enough to know that only one row will ever be returned, so there is no need to use the Assert. Well, that's all folks, I see you next week with more "Operators". Cheers, Fabiano

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  • C#/.NET Little Wonders: Constraining Generics with Where Clause

    - by James Michael Hare
    Back when I was primarily a C++ developer, I loved C++ templates.  The power of writing very reusable generic classes brought the art of programming to a brand new level.  Unfortunately, when .NET 1.0 came about, they didn’t have a template equivalent.  With .NET 2.0 however, we finally got generics, which once again let us spread our wings and program more generically in the world of .NET However, C# generics behave in some ways very differently from their C++ template cousins.  There is a handy clause, however, that helps you navigate these waters to make your generics more powerful. The Problem – C# Assumes Lowest Common Denominator In C++, you can create a template and do nearly anything syntactically possible on the template parameter, and C++ will not check if the method/fields/operations invoked are valid until you declare a realization of the type.  Let me illustrate with a C++ example: 1: // compiles fine, C++ makes no assumptions as to T 2: template <typename T> 3: class ReverseComparer 4: { 5: public: 6: int Compare(const T& lhs, const T& rhs) 7: { 8: return rhs.CompareTo(lhs); 9: } 10: }; Notice that we are invoking a method CompareTo() off of template type T.  Because we don’t know at this point what type T is, C++ makes no assumptions and there are no errors. C++ tends to take the path of not checking the template type usage until the method is actually invoked with a specific type, which differs from the behavior of C#: 1: // this will NOT compile! C# assumes lowest common denominator. 2: public class ReverseComparer<T> 3: { 4: public int Compare(T lhs, T rhs) 5: { 6: return lhs.CompareTo(rhs); 7: } 8: } So why does C# give us a compiler error even when we don’t yet know what type T is?  This is because C# took a different path in how they made generics.  Unless you specify otherwise, for the purposes of the code inside the generic method, T is basically treated like an object (notice I didn’t say T is an object). That means that any operations, fields, methods, properties, etc that you attempt to use of type T must be available at the lowest common denominator type: object.  Now, while object has the broadest applicability, it also has the fewest specific.  So how do we allow our generic type placeholder to do things more than just what object can do? Solution: Constraint the Type With Where Clause So how do we get around this in C#?  The answer is to constrain the generic type placeholder with the where clause.  Basically, the where clause allows you to specify additional constraints on what the actual type used to fill the generic type placeholder must support. You might think that narrowing the scope of a generic means a weaker generic.  In reality, though it limits the number of types that can be used with the generic, it also gives the generic more power to deal with those types.  In effect these constraints says that if the type meets the given constraint, you can perform the activities that pertain to that constraint with the generic placeholders. Constraining Generic Type to Interface or Superclass One of the handiest where clause constraints is the ability to specify the type generic type must implement a certain interface or be inherited from a certain base class. For example, you can’t call CompareTo() in our first C# generic without constraints, but if we constrain T to IComparable<T>, we can: 1: public class ReverseComparer<T> 2: where T : IComparable<T> 3: { 4: public int Compare(T lhs, T rhs) 5: { 6: return lhs.CompareTo(rhs); 7: } 8: } Now that we’ve constrained T to an implementation of IComparable<T>, this means that our variables of generic type T may now call any members specified in IComparable<T> as well.  This means that the call to CompareTo() is now legal. If you constrain your type, also, you will get compiler warnings if you attempt to use a type that doesn’t meet the constraint.  This is much better than the syntax error you would get within C++ template code itself when you used a type not supported by a C++ template. Constraining Generic Type to Only Reference Types Sometimes, you want to assign an instance of a generic type to null, but you can’t do this without constraints, because you have no guarantee that the type used to realize the generic is not a value type, where null is meaningless. Well, we can fix this by specifying the class constraint in the where clause.  By declaring that a generic type must be a class, we are saying that it is a reference type, and this allows us to assign null to instances of that type: 1: public static class ObjectExtensions 2: { 3: public static TOut Maybe<TIn, TOut>(this TIn value, Func<TIn, TOut> accessor) 4: where TOut : class 5: where TIn : class 6: { 7: return (value != null) ? accessor(value) : null; 8: } 9: } In the example above, we want to be able to access a property off of a reference, and if that reference is null, pass the null on down the line.  To do this, both the input type and the output type must be reference types (yes, nullable value types could also be considered applicable at a logical level, but there’s not a direct constraint for those). Constraining Generic Type to only Value Types Similarly to constraining a generic type to be a reference type, you can also constrain a generic type to be a value type.  To do this you use the struct constraint which specifies that the generic type must be a value type (primitive, struct, enum, etc). Consider the following method, that will convert anything that is IConvertible (int, double, string, etc) to the value type you specify, or null if the instance is null. 1: public static T? ConvertToNullable<T>(IConvertible value) 2: where T : struct 3: { 4: T? result = null; 5:  6: if (value != null) 7: { 8: result = (T)Convert.ChangeType(value, typeof(T)); 9: } 10:  11: return result; 12: } Because T was constrained to be a value type, we can use T? (System.Nullable<T>) where we could not do this if T was a reference type. Constraining Generic Type to Require Default Constructor You can also constrain a type to require existence of a default constructor.  Because by default C# doesn’t know what constructors a generic type placeholder does or does not have available, it can’t typically allow you to call one.  That said, if you give it the new() constraint, it will mean that the type used to realize the generic type must have a default (no argument) constructor. Let’s assume you have a generic adapter class that, given some mappings, will adapt an item from type TFrom to type TTo.  Because it must create a new instance of type TTo in the process, we need to specify that TTo has a default constructor: 1: // Given a set of Action<TFrom,TTo> mappings will map TFrom to TTo 2: public class Adapter<TFrom, TTo> : IEnumerable<Action<TFrom, TTo>> 3: where TTo : class, new() 4: { 5: // The list of translations from TFrom to TTo 6: public List<Action<TFrom, TTo>> Translations { get; private set; } 7:  8: // Construct with empty translation and reverse translation sets. 9: public Adapter() 10: { 11: // did this instead of auto-properties to allow simple use of initializers 12: Translations = new List<Action<TFrom, TTo>>(); 13: } 14:  15: // Add a translator to the collection, useful for initializer list 16: public void Add(Action<TFrom, TTo> translation) 17: { 18: Translations.Add(translation); 19: } 20:  21: // Add a translator that first checks a predicate to determine if the translation 22: // should be performed, then translates if the predicate returns true 23: public void Add(Predicate<TFrom> conditional, Action<TFrom, TTo> translation) 24: { 25: Translations.Add((from, to) => 26: { 27: if (conditional(from)) 28: { 29: translation(from, to); 30: } 31: }); 32: } 33:  34: // Translates an object forward from TFrom object to TTo object. 35: public TTo Adapt(TFrom sourceObject) 36: { 37: var resultObject = new TTo(); 38:  39: // Process each translation 40: Translations.ForEach(t => t(sourceObject, resultObject)); 41:  42: return resultObject; 43: } 44:  45: // Returns an enumerator that iterates through the collection. 46: public IEnumerator<Action<TFrom, TTo>> GetEnumerator() 47: { 48: return Translations.GetEnumerator(); 49: } 50:  51: // Returns an enumerator that iterates through a collection. 52: IEnumerator IEnumerable.GetEnumerator() 53: { 54: return GetEnumerator(); 55: } 56: } Notice, however, you can’t specify any other constructor, you can only specify that the type has a default (no argument) constructor. Summary The where clause is an excellent tool that gives your .NET generics even more power to perform tasks higher than just the base "object level" behavior.  There are a few things you cannot specify with constraints (currently) though: Cannot specify the generic type must be an enum. Cannot specify the generic type must have a certain property or method without specifying a base class or interface – that is, you can’t say that the generic must have a Start() method. Cannot specify that the generic type allows arithmetic operations. Cannot specify that the generic type requires a specific non-default constructor. In addition, you cannot overload a template definition with different, opposing constraints.  For example you can’t define a Adapter<T> where T : struct and Adapter<T> where T : class.  Hopefully, in the future we will get some of these things to make the where clause even more useful, but until then what we have is extremely valuable in making our generics more user friendly and more powerful!   Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,where,generics

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  • WPF Layout algorithm woes - control will resize, but not below some arbitrary value.

    - by Quantumplation
    I'm working on an application for a client, and one of the requirements is the ability to make appointments, and display the current week's appointments in a visual format, much like in Google Calender's or Microsoft Office. I found a great (3 part) article on codeproject, in which he builds a "RangePanel", and composes one for each "period" (for example, the work day.) You can find part 1 here: http://www.codeproject.com/KB/WPF/OutlookWpfCalendarPart1.aspx The code presents, but seems to choose an arbitrary height value overall (440.04), and won't resize below that without clipping. What I mean to say, is that the window/container will resize, but it just cuts off the bottom of the control, instead of recalculating the height of the range panels, and the controls in the range panels representing the appointment. It will resize and recalculate for greater values, but not less. Code-wise, what's happening is that when you resize below that value, first the "MeasureOverride" is called with the correct "new height". However, by the time the "ArrangeOverride" method is called, it's passing the same 440.04 value as the height to arrange to. I need to find a solution/workaround, but any information that you can provide that might direct me for things to look into would also be greatly appreciated ( I understand how frustrating it is to debug code when you don't have the codebase in front of you. :) ) The code for the various Arrange and Measure functions are provided below. The "CalendarView" control has a "CalendarViewContentPresenter", which handles several periods. Then, the periods have a "CalendarPeriodContentPresenter", which handles each "block" of appointments. Finally, the "RangePanel" has it's own implementation. (To be honest, i'm still a bit hazy on how the control works, so if my explanations are a bit hazy, the article I linked probably has a more cogent explanation. :) ) CalendarViewContentPresenter: protected override Size ArrangeOverride(Size finalSize) { int columnCount = this.CalendarView.Periods.Count; Size columnSize = new Size(finalSize.Width / columnCount, finalSize.Height); double elementX = 0; foreach (UIElement element in this.visualChildren) { element.Arrange(new Rect(new Point(elementX, 0), columnSize)); elementX = elementX + columnSize.Width; } return finalSize; } protected override Size MeasureOverride(Size constraint) { this.GenerateVisualChildren(); this.GenerateListViewItemVisuals(); // If it's coming back infinity, just return some value. if (constraint.Width == Double.PositiveInfinity) constraint.Width = 10; if (constraint.Height == Double.PositiveInfinity) constraint.Height = 10; return constraint; } CalendarViewPeriodPersenter: protected override Size ArrangeOverride(Size finalSize) { foreach (UIElement element in this.visualChildren) { element.Arrange(new Rect(new Point(0, 0), finalSize)); } return finalSize; } protected override Size MeasureOverride(Size constraint) { this.GenerateVisualChildren(); return constraint; } RangePanel: protected override Size ArrangeOverride(Size finalSize) { double containerRange = (this.Maximum - this.Minimum); foreach (UIElement element in this.Children) { double begin = (double)element.GetValue(RangePanel.BeginProperty); double end = (double)element.GetValue(RangePanel.EndProperty); double elementRange = end - begin; Size size = new Size(); size.Width = (Orientation == Orientation.Vertical) ? finalSize.Width : elementRange / containerRange * finalSize.Width; size.Height = (Orientation == Orientation.Vertical) ? elementRange / containerRange * finalSize.Height : finalSize.Height; Point location = new Point(); location.X = (Orientation == Orientation.Vertical) ? 0 : (begin - this.Minimum) / containerRange * finalSize.Width; location.Y = (Orientation == Orientation.Vertical) ? (begin - this.Minimum) / containerRange * finalSize.Height : 0; element.Arrange(new Rect(location, size)); } return finalSize; } protected override Size MeasureOverride(Size availableSize) { foreach (UIElement element in this.Children) { element.Measure(availableSize); } // Constrain infinities if (availableSize.Width == double.PositiveInfinity) availableSize.Width = 10; if (availableSize.Height == double.PositiveInfinity) availableSize.Height = 10; return availableSize; }

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  • Using DisplayTag library, I want to have the currently selected row have a unique custom class using

    - by Mary
    I have been trying to figure out how to highlight the selected row in a table. In my jsp I have jsp scriplet that can get access to the id of the row the displaytag library is creating. I want to compare it to the the id of the current row selected by the user ${currentNoteId}. Right now if the row id = 849 (hardcoded) the class "currentClass" is added to just that row of the table. I need to change the 849 for the {$currentNoteId} and I don't know how to do it. I am using java, Spring MVC. The jsp: ... <% request.setAttribute("dyndecorator", new org.displaytag.decorator.TableDecorator() { public String addRowClass() { edu.ilstu.ais.advisorApps.business.Note row = (edu.ilstu.ais.advisorApps.business.Note)getCurrentRowObject(); String rowId = row.getId(); if ( rowId.equals("849") ) { return "currentClass"; } return null; } }); %> <c:set var="currentNoteId" value="${studentNotes.currentNote.id}"/> ... <display:table id="noteTable" name="${ studentNotes.studentList }" pagesize="20" requestURI="notesView.form.html" decorator="dyndecorator"> <display:column title="Select" class="yui-button-match" href="/notesView.form.html" paramId="note.id" paramProperty="id"> <input type="button" class="yui-button-match2" name="select" value="Select"/> </display:column> <display:column property="userName" title="Created By" sortable="true"/> <display:column property="createDate" title="Created On" sortable="true" format="{0,date,MM/dd/yy hh:mm:ss a}"/> <display:column property="detail" title="Detail" sortable="true"/> </display:table> ... This could also get done using javascript and that might be best, but the documentation suggested this so I thought I would try it. I cannot find an example anywhere using the addRowClass() unless the comparison is to a field already in the row (a dollar amount is used in the documentation example) or hardcoded in like the "849" id. Thanks for any help you can provide.

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  • Is there a non-unique-key sorted list generic collection in C#?

    - by kdt
    I'm a bit surprised by System.Collections.Generic.SortedList, in that It requires me to use <key, value> instead of <value>(comparer) It only allows on entry per value These seem quirky in the way I want to use it (although I'm sure they're just right for other situations). Is there another collection that doesn't have these two characteristics?

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  • How can i count the number of unique instances of IP address in the following string in ruby

    - by kamal
    "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" "10.1.3.1" nil "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" "10.1.3.4" nil "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" "10.1.3.10" nil "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" "10.1.3.11" nil "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" "10.1.3.12" nil "10.1.3.30" "10.1.3.30" nil "10.1.3.38" "10.1.3.38" "10.1.3.38" "10.1.3.38" "10.1.3.38" nil "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" "10.1.3.55" nil "10.1.3.60" "10.1.3.60" "10.1.3.60" "10.1.3.60" "10.1.3.60" "10.1.3.60" "10.1.3.60" nil "10.1.3.66" "10.1.3.66" "10.1.3.66" "10.1.3.66" "10.1.3.66" "10.1.3.66" "10.1.3.66" nil "10.1.3.101" "10.1.3.101" nil "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" "10.1.3.102" nil "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" "10.1.3.103" nil "10.1.3.104" "10.1.3.104" nil "10.1.3.106" "10.1.3.106" nil "10.1.3.107" "10.1.3.107" "10.1.3.107" "10.1.3.107" "10.1.3.107" "10.1.3.107" "10.1.3.107" nil "10.1.3.108" "10.1.3.108" "10.1.3.108" "10.1.3.108" "10.1.3.108" "10.1.3.108" nil "10.1.3.110" "10.1.3.110" "10.1.3.110" "10.1.3.110" "10.1.3.110" nil the above string is stdout of: #!/usr/bin/ruby require "rubygems" require "fastercsv" scannedIPs = Hash.new(0) count = 0 FCSV.foreach("HOUND-1.csv", :headers => true, :skip_blanks => false) do |row| text = row[1] p text end

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  • URL length and content optimised for SEO [closed]

    - by Brendan Vogt
    Possible Duplicate: What is the best stucture of SEO friendly URL? I have done some reading on what URLS should look like for search engine optimisation, but I am curious to know how mine would like, I need some advice. I have a tutorial website, and my categories is something like: Web Development -> Client Side -> JavaScript So if I have a tutorial called "What is JavaScript?", is it good to have a URL that looks something like: www.MyWebsite.com/web-development/client-side/javascript/what-is-javascipt Or would something like this be more appropriate: www.MyWebsite.com/tutorials/what-is-javascipt Just curious because I also read that it is wise to have keywords in your URLs. Do I need to add the identifiers of each categories in the link as well, something like: www.MyWebsite.com/1/web-development/5/client-side/15/javascript/100/what-is-javascipt 1 is the unique identifier (primary key) of category web development 5 is the unique identifier (primary key) of category client side 15 is the unique identifier (primary key) of category javascript 100 is the unique identifier (primary key) of tutorial what is javascript

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  • How is my password sent across when I check gmails/access bank site [closed]

    - by learnerforever
    What encryption is used when my password is sent across in gmails/when I do online banking? RSA? DSA? Public-private key encryption?. In key encryption, which entity is assigned a public/private key? Does each unique machine with unique MAC address has a unique public/private key? Does each instance of browser have unique key? Does each user have unique private/public key? How does session key come into picture? How do machines receive their keys?

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  • Bug in CF9: values for unique struct keys referenced and overwritten by other keys.

    - by Gin Doe
    We've run into a serious issue with CF9 wherein values for certain struct keys can be referenced by other keys, despite those other keys never being set. See the following examples: Edit: Looks like it isn't just something our servers ate. This is Adobe bug-track ticket 81884: http://cfbugs.adobe.com/cfbugreport/flexbugui/cfbugtracker/main.html#bugId=81884. <cfset a = { AO = "foo" } /> <cfset b = { AO = "foo", B0 = "bar" } /> <cfoutput> The following should throw an error. Instead both keys refer to the same value. <br />Struct a: <cfdump var="#a#" /> <br />a.AO: #a.AO# <br />a.B0: #a.B0# <hr /> The following should show a struct with 2 distinct keys and values. Instead it contains a single key, "AO", with a value of "bar". <br />Struct b: <cfdump var="#b#" /> This is obviously a complete show-stopper for us. I'd be curious to know if anyone has encountered this or can reproduce this in their environment. For us, it happens 100% of the time on Apache/CF9 running on Linux, both RH4 and RH5. We're using the default JRun install on Java 1.6.0_14. To see the extent of the problem, we ran a quick loop to find other naming sequences that are affected and found hundreds of matches for 2 letter key names. A similar loop found more conflicts in 3 letter names. <cfoutput>Testing a range of affected key combinations. This found hundreds of cases on our platform. Aborting after 50 here.</cfoutput> <cfscript> teststring = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; stringlen = len(teststring); matchesfound = 0; matches = ""; for (i1 = 1; i1 <= stringlen; i1++) { symbol1 = mid(teststring, i1, 1); for (i2 = 1; i2 <= stringlen; i2++) { teststruct = structnew(); symbol2 = mid(teststring, i2, 1); symbolwhole = symbol1 & symbol2; teststruct[ symbolwhole ] = "a string"; for (q1 = 1; q1 <= stringlen; q1++) { innersymbol1 = mid(teststring, q1, 1); for (q2 = 1; q2 <= stringlen; q2++) { innersymbol2 = mid(teststring, q2, 1); innersymbolwhole = innersymbol1 & innersymbol2; if ((i1 != q1 || i2 != q2) && structkeyexists(teststruct, innersymbolwhole)) { // another affected pair of keys! writeoutput ("<br />#symbolwhole# = #innersymbolwhole#"); if (matchesfound++ > 50) { // we've seen enough abort; } } } } } } </cfscript> And edit again: This doesn't just affect struct keys but names in the variables scope as well. At least the variables scope has the presence of mind to throw an error, "can't load a null": <cfset test_b0 = "foo" /> <cfset test_ao = "bar" /> <cfoutput> test_b0: #test_b0# <br />test_ao: #test_ao# </cfoutput>

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  • Securing WebSocket applications on Glassfish

    - by Pavel Bucek
    Today we are going to cover deploying secured WebSocket applications on Glassfish and access to these services using WebSocket Client API. WebSocket server application setup Our server endpoint might look as simple as this: @ServerEndpoint("/echo") public class EchoEndpoint { @OnMessage   public String echo(String message) {     return message + " (from your server)";   } } Everything else must be configured on container level. We can start with enabling SSL, which will require web.xml to be added to your project. For starters, it might look as following: <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee">   <security-constraint>     <web-resource-collection>       <web-resource-name>Protected resource</web-resource-name>       <url-pattern>/*</url-pattern>       <http-method>GET</http-method>     </web-resource-collection>     <!-- https -->     <user-data-constraint>       <transport-guarantee>CONFIDENTIAL</transport-guarantee>     </user-data-constraint>   </security-constraint> </web-app> This is minimal web.xml for this task - web-resource-collection just defines URL pattern and HTTP method(s) we want to put a constraint on and user-data-constraint defines that constraint, which is in our case transport-guarantee. More information about these properties and security settings for web application can be found in Oracle Java EE 7 Tutorial. I have some simple webpage attached as well, so I can test my endpoint right away. You can find it (along with complete project) in Tyrus workspace: [webpage] [whole project]. After deploying this application to Glassfish Application Server, you should be able to hit it using your favorite browser. URL where my application resides is https://localhost:8181/sample-echo-https/ (may be different, depends on other configuration). My browser warns me about untrusted certificate (I use what freshly built Glassfish provides - self signed certificates) and after adding an exception for this site, I can see my webpage and I am able to securely connect to wss://localhost:8181/sample-echo-https/echo. WebSocket client Already mentioned demo application also contains test client, but execution of this is skipped for normal build. Reason for this is that Glassfish uses these self-signed "random" untrusted certificates and you are (in most cases) not able to connect to these services without any additional settings. Creating test WebSocket client is actually quite similar to server side, only difference is that you have to somewhere create client container and invoke connect with some additional info. Java API for WebSocket allows you to use annotated and programmatic way to construct endpoints. Server side shows the annotated case, so let's see how the programmatic approach will look. final WebSocketContainer client = ContainerProvider.getWebSocketContainer(); client.connectToServer(new Endpoint() {   @Override   public void onOpen(Session session, EndpointConfig EndpointConfig) {     try {       // register message handler - will just print out the       // received message on standard output.       session.addMessageHandler(new MessageHandler.Whole<String>() {       @Override         public void onMessage(String message) {          System.out.println("### Received: " + message);         }       });       // send a message       session.getBasicRemote().sendText("Do or do not, there is no try.");     } catch (IOException e) {       // do nothing     }   } }, ClientEndpointConfig.Builder.create().build(),    URI.create("wss://localhost:8181/sample-echo-https/echo")); This client should work with some secured endpoint with valid certificated signed by some trusted certificate authority (you can try that with wss://echo.websocket.org). Accessing our Glassfish instance will require some additional settings. You can tell Java which certificated you trust by adding -Djavax.net.ssl.trustStore property (and few others in case you are using linked sample). Complete command line when you are testing your service might need to look somewhat like: mvn clean test -Djavax.net.ssl.trustStore=$AS_MAIN/domains/domain1/config/cacerts.jks\ -Djavax.net.ssl.trustStorePassword=changeit -Dtyrus.test.host=localhost\ -DskipTests=false Where AS_MAIN points to your Glassfish instance. Note: you might need to setup keyStore and trustStore per client instead of per JVM; there is a way how to do it, but it is Tyrus proprietary feature: http://tyrus.java.net/documentation/1.2.1/user-guide.html#d0e1128. And that's it! Now nobody is able to "hear" what you are sending to or receiving from your WebSocket endpoint. There is always room for improvement, so the next step you might want to take is introduce some authentication mechanism (like HTTP Basic or Digest). This topic is more about container configuration so I'm not going to go into details, but there is one thing worth mentioning: to access services which require authorization, you might need to put this additional information to HTTP headers of first (Upgrade) request (there is not (yet) any direct support even for these fundamental mechanisms, user need to register Configurator and add headers in beforeRequest method invocation). I filed related feature request as TYRUS-228; feel free to comment/vote if you need this functionality.

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