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• How to Save data in txt file in MATLAB

  - by Jessy

  I have 3 txt files s1.txt, s2.txt, s3.txt.Each have the same format and number of data.I want to combine only the second column of each of the 3 files into one file. Before I combine the data, I sorted it according to the 1st column: UnSorted file: s1.txt s2.txt s3.txt 1 23 2 33 3 22 4 32 4 32 2 11 5 22 1 10 5 28 2 55 8 11 7 11 Sorted file: s1.txt s2.txt s3.txt 1 23 1 10 2 11 2 55 2 33 3 22 4 32 4 32 5 28 5 22 8 11 7 11 Here is the code I have so far: BaseFile ='s' n=3 fid=fopen('RT.txt','w'); for i=1:n %Open each file consecutively d(i)=fopen([BaseFile num2str(i)'.txt']); %read data from file A=textscan(d(i),'%f%f') a=A{1} b=A{2} ab=[a,b]; %sort the data according to the 1st column B=sortrows(ab,1); %delete the 1st column after being sorted B(:,1)=[] %write to a new file fprintf(fid,'%d\n',B'); %close (d(i)); end fclose(fid); How can I get the output in the new txt file in this format? 23 10 11 55 33 22 32 32 28 22 11 11 instead of this format? 23 55 32 22 10 33 32 11 11 22 28 11

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• How to alter Postgres table data based on its contents?

  - by williamjones

  This is probably a super simple question, but I'm struggling to come up with the right keywords to find it on Google. I have a Postgres table that has among its contents a column of type text named content_type. That stores what type of entry is stored in that row. There are only about 5 different types, and I decided I want to change one of them to display as something else in my application (I had been directly displaying these). It struck me that it's funny that my view is being dictated by my database model, and I decided I would convert the types being stored in my database as strings into integers, and enumerate the possible types in my application with constants that convert them into their display names. That way, if I ever got the urge to change any category names again, I could just change it with one alteration of a constant. I also have the hunch that storing integers might be somewhat more efficient than storing text in the database. First, a quick threshold question of, is this a good idea? Any feedback or anything I missed? Second, and my main question, what's the Postgres command I could enter to make an alteration like this? I'm thinking I could start by renaming the old content_type column to old_content_type and then creating a new integer column content_type. However, what command would look at a row's old_content_type and fill in the new content_type column based off of that?

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• Rendering partial for table row with form_tag is getting crazy!

  - by xopht

  I have 23(column)x6(row) table and change the row with link_to_remote function. each tr tag has its own id attribute. change link call change action and change action changes the row using render function wit partial. _change.html.erb <td id="row_1">1</td> . . omitted . . <td id="row_23">23</td> link_to_remote function <%= link_to_remote 'Change', :update => 'row_1', :url => change_path %> change action def change logger.debug render :partial => 'change' end If I coded like above, everything work okay. This means all changed-columns are in one row. But, if I wrap partial code with *form_for* function like below... <% form_for 'change' do %> <td id="row_1">1</td> . . omitted . . <td id="row_23">23</td> <% end %> Then, one column located in one row and that column is the first column. I've looked up the log file, but it was normal html tags. What's wrong?

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• Stop writing blank line at the end of CSV file (using MATLAB)

  - by Grant M.

  Hello all ... I'm using MATLAB to open a batch of CSV files containing column headers and data (using the 'importdata' function), then I manipulate the data a bit and write the headers and data to new CSV files using the 'dlmwrite' function. I'm using the '-append' and 'newline' attributes of 'dlmwrite' to add each line of text/data on a new line. Each of my new CSV files has a blank line at the end, whereas this blank line was not there before when I read in the data ... and I'm not using 'newline' on my final call of 'dlmwrite'. Does anyone know how I can keep from writing this blank line to the end of my CSV files? Thanks for your help, Grant EDITED 5/18/10 1:35PM CST - Added information about code and text file per request ... you'll notice after performing the procedure below that there appears to be a carriage return at the end of the last line in the new text file. Consider a text file named 'textfile.txt' that looks like this: Column1, Column2, Column3, Column4, Column 5 1, 2, 3, 4, 5 1, 2, 3, 4, 5 1, 2, 3, 4, 5 1, 2, 3, 4, 5 1, 2, 3, 4, 5 Here's a sample of the code I am using: % import data importedData = importdata('textfile.txt'); % manipulate data importedData.data(:,1) = 100; % store column headers into single comma-delimited % character array (for easy writing later) columnHeaders = importedData.textdata{1}; for counter = 2:size(importedData.textdata,2) columnHeaders = horzcat(columnHeaders,',',importedData.textdata{counter}); end % write column headers to new file dlmwrite('textfile_updated.txt',columnHeaders,'Delimiter','','newline','pc') % append all but last line of data to new file for dataCounter = 1:(size(importedData.data,2)-1) dlmwrite('textfile_updated.txt',importedData.data(dataCounter,:),'Delimiter',',','newline','pc','-append') end % append last line of data to new file, not % creating new line at end dlmwrite('textfile_updated.txt',importedData.data(end,:),'Delimiter',',','-append')

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• Using proxy models

  - by smallB

  I've created Proxy model by subclassing QAbstractProxyModel and connected it as a model to my view. I also set up source model for this proxy model. Unfortunately something is wrong because I'm not getting anything displayed on my listView (it works perfectly when I have my model supplied as a model to view but when I supply this proxy model it just doesn't work). Here are some snippets from my code: #ifndef FILES_PROXY_MODEL_H #define FILES_PROXY_MODEL_H #include <QAbstractProxyModel> #include "File_List_Model.h" class File_Proxy_Model: public QAbstractProxyModel { public: explicit File_Proxy_Model(File_List_Model* source_model) { setSourceModel(source_model); } virtual QModelIndex mapFromSource(const QModelIndex & sourceIndex) const { return index(sourceIndex.row(),sourceIndex.column()); } virtual QModelIndex mapToSource(const QModelIndex & proxyIndex) const { return index(proxyIndex.row(),proxyIndex.column()); } virtual int columnCount(const QModelIndex & parent = QModelIndex()) const { return sourceModel()->columnCount(); } virtual int rowCount(const QModelIndex & parent = QModelIndex()) const { return sourceModel()->rowCount(); } virtual QModelIndex index(int row, int column, const QModelIndex & parent = QModelIndex()) const { return createIndex(row,column); } virtual QModelIndex parent(const QModelIndex & index) const { return QModelIndex(); } }; #endif // FILES_PROXY_MODEL_H //and this is a dialog class: Line_Counter::Line_Counter(QWidget *parent) : QDialog(parent), model_(new File_List_Model(this)), proxy_model_(new File_Proxy_Model(model_)), sel_model_(new QItemSelectionModel(proxy_model_,this)) { setupUi(this); setup_mvc_(); } void Line_Counter::setup_mvc_() { listView->setModel(proxy_model_); listView->setSelectionModel(sel_model_); }

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• Performance of stored proc when updating columns selectively based on parameters?

  - by kprobst

  I'm trying to figure out if this is relatively well-performing T-SQL (this is SQL Server 2008). I need to create a stored procedure that updates a table. The proc accepts as many parameters as there are columns in the table, and with the exception of the PK column, they all default to NULL. The body of the procedure looks like this: CREATE PROCEDURE proc_repo_update @object_id bigint ,@object_name varchar(50) = NULL ,@object_type char(2) = NULL ,@object_weight int = NULL ,@owner_id int = NULL -- ...etc AS BEGIN update object_repo set object_name = ISNULL(@object_name, object_name) ,object_type = ISNULL(@object_type, object_type) ,object_weight = ISNULL(@object_weight, object_weight) ,owner_id = ISNULL(@owner_id, owner_id) -- ...etc where object_id = @object_id return @@ROWCOUNT END So basically: Update a column only if its corresponding parameter was provided, and leave the rest alone. This works well enough, but as the ISNULL call will return the value of the column if the received parameter was null, will SQL Server optimize this somehow? This might be a performance bottleneck on the application where the table might be updated heavily (insertion will be uncommon so the performance there is not a problem). So I'm trying to figure out what's the best way to do this. Is there a way to condition the column expressions with something like CASE WHEN or something? The table will be indexed up the wazoo as well for read performance. Is this the best approach? My alternative at this point is to create the UPDATE expression in code (e.g. inline SQL) and execute it against the server. This would solve my doubts about performance, but I'd rather leave this in a stored proc if possible.

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• How do I gather data from the same collumn in multiple worksheets in a single workbook?

  - by infiniteloop91

  Okay so here is what I want to accomplish. For this example I have a single workbook composed of 4 data sheets plus a totals sheet. Each of the 4 data sheets has a similar name following the same pattern where the only difference is the date. (Ex. 9854978_1009_US.txt, where 1009 is the date that changes while the rest of the file name is the same). In each of those documents column F contains a series of number that I would like to find the sum of but I will have no idea how many cells in F actually contain numbers. (However there will never be additional information below it the numbers so I could in theory just add the entire F column together). I will also add new files to the workbook over time and do not want to have to rewrite the code of which I gather my data from column F. Essentially what I would like to accomplish is for the 'totals' document to take every column F from documents in the workbook with the name of '9854978_????_US.txt', where the question marks change based on the file name. How would I go about doing this in pure Excel code?

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• Custom ADO.NET provider to intercept and modify sql queries.

  - by Faisal

  Our client has an application that stores blobs in database which has now grown enough to impact the performance of SQL Server. To overcome this issue, we are planning to offload all blobs to file system and leave the path of file in a new column in user table. Like if user has a table docs with columns id, name and content (blob); we would ask him to add a new column 'filepath' in this table. Our client is willing to make this change in this database. But when it comes to changing the sql queries to read and write into this table, they are not ready to accep this. Actually, they don't want any change that results in recompilation and deployment. Now we are planning to write a custom ADO.NET provider that will intercept the select queries add a column 'filepath' at the end of the select statement retieve the result set and modify the 'content' column value based on 'filepath' value Is there any use case that you think will certainly fail with this approach? I know this sounds dirty but do we have a better way?

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• How to further improve error messages in Scala parser-combinator based parsers?

  - by rse

  I've coded a parser based on Scala parser combinators: class SxmlParser extends RegexParsers with ImplicitConversions with PackratParsers { [...] lazy val document: PackratParser[AstNodeDocument] = ((procinst | element | comment | cdata | whitespace | text)*) ^^ { AstNodeDocument(_) } [...] } object SxmlParser { def parse(text: String): AstNodeDocument = { var ast = AstNodeDocument() val parser = new SxmlParser() val result = parser.parseAll(parser.document, new CharArrayReader(text.toArray)) result match { case parser.Success(x, _) => ast = x case parser.NoSuccess(err, next) => { tool.die("failed to parse SXML input " + "(line " + next.pos.line + ", column " + next.pos.column + "):\n" + err + "\n" + next.pos.longString) } } ast } } Usually the resulting parsing error messages are rather nice. But sometimes it becomes just sxml: ERROR: failed to parse SXML input (line 32, column 1): `"' expected but `' found ^ This happens if a quote characters is not closed and the parser reaches the EOT. What I would like to see here is (1) what production the parser was in when it expected the '"' (I've multiple ones) and (2) where in the input this production started parsing (which is an indicator where the opening quote is in the input). Does anybody know how I can improve the error messages and include more information about the actual internal parsing state when the error happens (perhaps something like a production rule stacktrace or whatever can be given reasonably here to better identify the error location). BTW, the above "line 32, column 1" is actually the EOT position and hence of no use here, of course.

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• decoding jquery json data in php

  - by Mac Taylor

  hey guys recenlty i made a script to move objects and save the orders now i have a little to do to finish this script everything works fine , just one question : how can i save not numeric data in my json script this is my script : function updateWidgetData(){ var items=[]; $('.widget-title').each(function(){ var weightId=$(this).attr('id'); $('.column').each(function(){ var columnId=$(this).attr('id'); $('.widget', this).each(function(i){ var collapsed=0; if($(this).find('.widget-inside').css('display')=="none") collapsed=1; //Create Item object for current panel var item={ id: $(this).attr('id'), collapsed: collapsed, order : i, column: columnId, weight: weightId }; //Push item object into items array items.push(item); }); }); }); //Assign items array to sortorder JSON variable var sortorder={ items: items }; //Pass sortorder variable to server using ajax to save state $.post('updatePanels.php', 'data='+$.toJSON(sortorder), function(response){ if(response=="success") $("#console").html('<div class="success">Saved</div>').hide().fadeIn(1000); setTimeout(function(){ $('#console').fadeOut(1000); }, 2000); }); } and this is my php script : $data=json_decode($_POST["data"]); foreach($data->items as $item) { //Extract column number for panel $col_id=preg_replace('/[^\d\s]/', '', $item->column); //Extract id of the panel $widget_id=preg_replace('/[^\d\s]/', '', $item->id); $sql="UPDATE widgets SET column_id='$col_id', sort_no='".$item->order."', collapsed='".$item->collapsed."' WHERE id='".$widget_id."'"; mysql_query($sql) or die('Error updating widget DB'); } echo "success"; everything works fine till i use numeric value for columns' id but i need non numeric values forexample id='columnr' i want to extract r but i cant get it right any help plz !?

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• Telling me my stored procedure isn't declared

  - by Scott

  Here is where the error is occuring in the stack: public static IKSList<DataParameter> Search(int categoryID, int departmentID, string title) { Database db = new Database(DatabaseConfig.CommonConnString, DatabaseConfig.CommonSchemaOwner, "pkg_data_params_new", "spdata_params_search"); db.AddParameter("category_id", categoryID); db.AddParameter("department_id", departmentID); db.AddParameter("title", title, title.Length); DataView temp = db.Execute_DataView(); IKSList<DataParameter> dps = new IKSList<DataParameter>(); foreach (DataRow dr in temp.Table.Rows) { DataParameter dp = new DataParameter(); dp.Load(dr); dps.Add(dp); } return dps; } And here is the error text: ORA-06550: line 1, column 38: PLS-00302: component 'SPDATA_PARAMS_SEARCH' must be declared ORA-06550: line 1, column 7: PL/SQL: Statement ignored Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.OracleClient.OracleException: ORA-06550: line 1, column 38: PLS-00302: component 'SPDATA_PARAMS_SEARCH' must be declared ORA-06550: line 1, column 7: PL/SQL: Statement ignored Source Error: Line 161: db.AddParameter("title", title, title.Length); Line 162: Line 163: DataView temp = db.Execute_DataView(); Line 164: Line 165: IKSList dps = new IKSList(); My webconfig is pointing to the correct place and everything so idk where this is coming from.

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• How to implement button in a vector

  - by user1880497

  In my table. I want to put some buttons into each row that I can press. But I do not know how to do it public static DefaultTableModel buildTableModel(ResultSet rs) throws SQLException { java.sql.ResultSetMetaData metaData = rs.getMetaData(); // names of columns Vector<String> columnNames = new Vector<String>(); int columnCount = metaData.getColumnCount(); for (int column = 1; column <= columnCount; column++) { columnNames.add(metaData.getColumnName(column)); } // data of the table Vector<Vector<Object>> data = new Vector<Vector<Object>>(); while (rs.next()) { Vector<Object> vector = new Vector<Object>(); for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) { vector.add(rs.getObject(columnIndex)); } data.add(vector); } return new DefaultTableModel(data, columnNames); }

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• Need a set based solution to group rows

  - by KM

  I need to group a set of rows based on the Category column, and also limit the combined rows based on the SUM(Number) column to be less than or equal to the @Limit value. For each distinct Category column I need to identify "buckets" that are <=@limit. If the SUM(Number) of all the rows for a Category column are <=@Limit then there will be only 1 bucket for that Category value (like 'CCCC' in the sample data). However if the SUM(Number)@limit, then there will be multiple bucket rows for that Category value (like 'AAAA' in the sample data), and each bucket must be <=@Limit. There can be as many buckets as necessary. Also, look at Category value 'DDDD', its one row is greater than @Limit all by itself, and gets split into two rows in the result set. Given this simplified data: DECLARE @Detail table (DetailID int primary key, Category char(4), Number int) SET NOCOUNT ON INSERT @Detail VALUES ( 1, 'AAAA',100) INSERT @Detail VALUES ( 2, 'AAAA', 50) INSERT @Detail VALUES ( 3, 'AAAA',300) INSERT @Detail VALUES ( 4, 'AAAA',200) INSERT @Detail VALUES ( 5, 'BBBB',500) INSERT @Detail VALUES ( 6, 'CCCC',200) INSERT @Detail VALUES ( 7, 'CCCC',100) INSERT @Detail VALUES ( 8, 'CCCC', 50) INSERT @Detail VALUES ( 9, 'DDDD',800) INSERT @Detail VALUES (10, 'EEEE',100) SET NOCOUNT OFF DECLARE @Limit int SET @Limit=500 I need one of these result set: DetailID Bucket | DetailID Category Bucket -------- ------ | -------- -------- ------ 1 1 | 1 'AAAA' 1 2 1 | 2 'AAAA' 1 3 1 | 3 'AAAA' 1 4 2 | 4 'AAAA' 2 5 3 OR 5 'BBBB' 1 6 4 | 6 'CCCC' 1 7 4 | 7 'CCCC' 1 8 4 | 8 'CCCC' 1 9 5 | 9 'DDDD' 1 9 6 | 9 'DDDD' 2 10 7 | 10 'EEEE' 1

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• Joining tables with composite keys in a legacy system in hibernate

  - by Steve N

  Hi, I'm currently trying to create a pair of Hibernate annotated classes to load (read only) from a pair of tables in a legacy system. The legacy system uses a consistent (if somewhat dated) approach to keying tables. The tables I'm attempting to map are as follows: Customer CustomerAddress -------------------------- ---------------------------- customerNumber:string (pk) customerNumber:string (pk_1) name:string sequenceNumber:int (pk_2) street:string postalCode:string I've approached this by creating a CustomerAddress class like this: @Entity @Table(name="CustomerAddress") @IdClass(CustomerAddressKey.class) public class CustomerAddress { @Id @AttributeOverrides({ @AttributeOverride(name = "customerNumber", column = @Column(name="customerNumber")), @AttributeOverride(name = "sequenceNumber", column = @Column(name="sequenceNumber")) }) private String customerNumber; private int sequenceNumber; private String name; private String postalCode; ... } Where the CustomerAddressKey class is a simple Serializable object with the two key fields. The Customer object is then defined as: @Entity @Table(name = "Customer") public class Customer { private String customerNumber; private List<CustomerAddress> addresses = new ArrayList<CustomerAddress>(); private String name; ... } So, my question is: how do I express the OneToMany relationship on the Customer table?

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• The most efficient way to calculate an integral in a dataset range

  - by Annalisa

  I have an array of 10 rows by 20 columns. Each columns corresponds to a data set that cannot be fitted with any sort of continuous mathematical function (it's a series of numbers derived experimentally). I would like to calculate the integral of each column between row 4 and row 8, then store the obtained result in a new array (20 rows x 1 column). I have tried using different scipy.integrate modules (e.g. quad, trpz,...). The problem is that, from what I understand, scipy.integrate must be applied to functions, and I am not sure how to convert each column of my initial array into a function. As an alternative, I thought of calculating the average of each column between row 4 and row 8, then multiply this number by 4 (i.e. 8-4=4, the x-interval) and then store this into my final 20x1 array. The problem is...ehm...that I don't know how to calculate the average over a given range. The question I am asking are: Which method is more efficient/straightforward? Can integrals be calculated over a data set like the one that I have described? How do I calculate the average over a range of rows?

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• Passing trough a datagrid value

  - by Tonz

  I have a datagrid with 2 columns. One databound which display names and the other one is a hyperlink column. Column1 = databound column, Column2 = hyperlink column. column1: column2: --------------------- Name1 Modify Name2 Modify Next when i click on any of the values in Column2 i simply get redirected to a other page. This page contains 2 buttons/hyperlinks with Yes or No. (does not mather wich control, which one would bring the most easy to implement solution atm) When clicked on No it simply redirects back to the orignal page. Now the question is when i press "Yes" how exactly do i acces "Name1" (or Name2 if i press on the second modify)? Meaning if i press Yes i want to use this Name for certain opertions (xml). To put it short if i press on "modify" i want to be able to get that name associated with it (which is already displayed in the first bound column left of it). So the goal is to use that name in Xpath for example so i can make a query towards that node with that certain name. Hopefully this made some sence.

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• Why does p:panelGrid not work with ui:repeat?

  - by CycDemo

  If I use as below, I get no error, no output. Why does p:panelGrid not work with ui:repeat? Note : I don't want to use c:forEach because of the I already face a lot of JSF issue. <p:panelGrid> <ui:repeat value="#{MyBean.dataList}" var="data"> <p:row> <p:column> <h:outputText value="#{data.name}"/> </p:column> <p:column> <h:outputText value="#{data.description}"/> </p:column> </p:row> </ui:repeat> </p:panelGrid> MyBean.java public List<Data> getDataList(){ List<Data> result = new ArrayList<Data>(); result.add(new Data("Name 1", "Description 1")); result.add(new Data("Name 2", "Description 2")); result.add(new Data("Name 3", "Description 3")); result.add(new Data("Name 4", "Description 4")); return result; } Expected output with primefaces

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• java class that simulates a simple database table

  - by ericso

  I have a collection of heterogenous data that I pull from a database table mtable. Then, for every unique value uv in column A, I compute a function of (SELECT * FROM mtable WHERE A=uv). Then I do the same for column B, and column C. There are rather a lot of unique values, so I don't want to hit the db repeatedly - I would rather have a class that replicates some of the functionality (most importantly some version of SELECT WHERE). Additionally, I would like to abstract the column names away from the class definition, if that makes any sense - the constructor should take a list of names as a parameter, and also, I suppose, a list of types (right now this is just a String[], which seems hacky). I'm getting the initial data from a RowSet. I've more or less done this by using a hashmap that maps Strings to lists/arrays of Objects, but I keep getting bogged down in comparisons and types, and am thinking that my current implementation really isn't as clean and clear as it could be. I'm pretty new to java, also, and am not sure if I'm not going down a completely incorrect path. Does anyone have any suggestions?

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• Transfering data from Excel to dataGridView

  - by Panecillo

  I have a problem when I want to transfer data from Excel to dataGridView in C#. My Excel's column has numeric and alphanumeric values. But for example, if the column has 3 numbers and 2 alphanumeric values then only the numbers are shown in the dataGridView, and vice versa. Why aren't all the values shown? The next is what happen: Excel's Column: DataGridView's Column: 45654 45654 P745K 31233 31233 23111 23111 45X2Y Here is my code to load the dataGridView: string connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\test.xls;Extended Properties=""Excel 8.0;HDR=YES;"""; DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.OleDb"); DbDataAdapter adapter = factory.CreateDataAdapter(); DbCommand selectCommand = factory.CreateCommand(); selectCommand.CommandText = "SELECT * FROM [sheet1$]"; DbConnection connection = factory.CreateConnection(); connection.ConnectionString = connectionString; selectCommand.Connection = connection; adapter.SelectCommand = selectCommand; data = new DataSet(); adapter.Fill(data); dataGridView1.DataSource = data.Tables[0].DefaultView; I hope I explained it well. Sorry my bad english. Thanks.

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• Java nullPointerException with getter and setters on an object

  - by 12345

  I'm getting a nullPointerException below. Can someone explain why? Thanks! private SpatialPooler spatialPooler; private Region region; private Column column33; public void setUp() { this.spatialPooler = new SpatialPooler(); this.region = new Region(30, 40, 6, 8, 1.0f, 1, 1); this.column33 = this.region.getColumn(3, 3); } public void addActiveColumn(Column activeColumn) { this.activeColumns.add(activeColumn); // nullPointerException here! } public Column getActiveColumn(int x, int y) { for (Column activeColumn : this.activeColumns) { if (activeColumn.getX() == x && activeColumn.getY() == y) { return activeColumn; } } return null; } // in a test class that is in the same package. public void testGetAndAddActiveColumn() { this.spatialPooler.addActiveColumn(this.column33); assertNull(this.spatialPooler.getActiveColumn(3, 3)); this.column33.setActiveState(true); assertEquals(this.column33, this.spatialPooler.getActiveColumn(3, 3)); }

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• SQL Monitor’s data repository

  - by Chris Lambrou

  As one of the developers of SQL Monitor, I often get requests passed on by our support people from customers who are looking to dip into SQL Monitor’s own data repository, in order to pull out bits of information that they’re interested in. Since there’s clearly interest out there in playing around directly with the data repository, I thought I’d write some blog posts to start to describe how it all works. The hardest part for me is knowing where to begin, since the schema of the data repository is pretty big. Hmmm… I guess it’s tricky for anyone to write anything but the most trivial of queries against the data repository without understanding the hierarchy of monitored objects, so perhaps my first post should start there. I always imagine that whenever a customer fires up SSMS and starts to explore their SQL Monitor data repository database, they become immediately bewildered by the schema – that was certainly my experience when I did so for the first time. The following query shows the number of different object types in the data repository schema: SELECT type_desc, COUNT(*) AS [count] FROM sys.objects GROUP BY type_desc ORDER BY type_desc;  type_desccount 1DEFAULT_CONSTRAINT63 2FOREIGN_KEY_CONSTRAINT181 3INTERNAL_TABLE3 4PRIMARY_KEY_CONSTRAINT190 5SERVICE_QUEUE3 6SQL_INLINE_TABLE_VALUED_FUNCTION381 7SQL_SCALAR_FUNCTION2 8SQL_STORED_PROCEDURE100 9SYSTEM_TABLE41 10UNIQUE_CONSTRAINT54 11USER_TABLE193 12VIEW124 With 193 tables, 124 views, 100 stored procedures and 381 table valued functions, that’s quite a hefty schema, and when you browse through it using SSMS, it can be a bit daunting at first. So, where to begin? Well, let’s narrow things down a bit and only look at the tables belonging to the data schema. That’s where all of the collected monitoring data is stored by SQL Monitor. The following query gives us the names of those tables: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' ORDER BY sch.name, obj.name; This query still returns 110 tables. I won’t show them all here, but let’s have a look at the first few of them:  name 1data.Cluster_Keys 2data.Cluster_Machine_ClockSkew_UnstableSamples 3data.Cluster_Machine_Cluster_StableSamples 4data.Cluster_Machine_Keys 5data.Cluster_Machine_LogicalDisk_Capacity_StableSamples 6data.Cluster_Machine_LogicalDisk_Keys 7data.Cluster_Machine_LogicalDisk_Sightings 8data.Cluster_Machine_LogicalDisk_UnstableSamples 9data.Cluster_Machine_LogicalDisk_Volume_StableSamples 10data.Cluster_Machine_Memory_Capacity_StableSamples 11data.Cluster_Machine_Memory_UnstableSamples 12data.Cluster_Machine_Network_Capacity_StableSamples 13data.Cluster_Machine_Network_Keys 14data.Cluster_Machine_Network_Sightings 15data.Cluster_Machine_Network_UnstableSamples 16data.Cluster_Machine_OperatingSystem_StableSamples 17data.Cluster_Machine_Ping_UnstableSamples 18data.Cluster_Machine_Process_Instances 19data.Cluster_Machine_Process_Keys 20data.Cluster_Machine_Process_Owner_Instances 21data.Cluster_Machine_Process_Sightings 22data.Cluster_Machine_Process_UnstableSamples 23… There are two things I want to draw your attention to: The table names describe a hierarchy of the different types of object that are monitored by SQL Monitor (e.g. clusters, machines and disks). For each object type in the hierarchy, there are multiple tables, ending in the suffixes _Keys, _Sightings, _StableSamples and _UnstableSamples. Not every object type has a table for every suffix, but the _Keys suffix is especially important and a _Keys table does indeed exist for every object type. In fact, if we limit the query to return only those tables ending in _Keys, we reveal the full object hierarchy: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' AND obj.name LIKE '%_Keys' ORDER BY sch.name, obj.name;  name 1data.Cluster_Keys 2data.Cluster_Machine_Keys 3data.Cluster_Machine_LogicalDisk_Keys 4data.Cluster_Machine_Network_Keys 5data.Cluster_Machine_Process_Keys 6data.Cluster_Machine_Services_Keys 7data.Cluster_ResourceGroup_Keys 8data.Cluster_ResourceGroup_Resource_Keys 9data.Cluster_SqlServer_Agent_Job_History_Keys 10data.Cluster_SqlServer_Agent_Job_Keys 11data.Cluster_SqlServer_Database_BackupType_Backup_Keys 12data.Cluster_SqlServer_Database_BackupType_Keys 13data.Cluster_SqlServer_Database_CustomMetric_Keys 14data.Cluster_SqlServer_Database_File_Keys 15data.Cluster_SqlServer_Database_Keys 16data.Cluster_SqlServer_Database_Table_Index_Keys 17data.Cluster_SqlServer_Database_Table_Keys 18data.Cluster_SqlServer_Error_Keys 19data.Cluster_SqlServer_Keys 20data.Cluster_SqlServer_Services_Keys 21data.Cluster_SqlServer_SqlProcess_Keys 22data.Cluster_SqlServer_TopQueries_Keys 23data.Cluster_SqlServer_Trace_Keys 24data.Group_Keys The full object type hierarchy looks like this: Cluster Machine LogicalDisk Network Process Services ResourceGroup Resource SqlServer Agent Job History Database BackupType Backup CustomMetric File Table Index Error Services SqlProcess TopQueries Trace Group Okay, but what about the individual objects themselves represented at each level in this hierarchy? Well that’s what the _Keys tables are for. This is probably best illustrated by way of a simple example – how can I query my own data repository to find the databases on my own PC for which monitoring data has been collected? Like this: SELECT clstr._Name AS cluster_name, srvr._Name AS instance_name, db._Name AS database_name FROM data.Cluster_SqlServer_Database_Keys db JOIN data.Cluster_SqlServer_Keys srvr ON db.ParentId = srvr.Id -- Note here how the parent of a Database is a Server JOIN data.Cluster_Keys clstr ON srvr.ParentId = clstr.Id -- Note here how the parent of a Server is a Cluster WHERE clstr._Name = 'dev-chrisl2' -- This is the hostname of my own PC ORDER BY clstr._Name, srvr._Name, db._Name;  cluster_nameinstance_namedatabase_name 1dev-chrisl2SqlMonitorData 2dev-chrisl2master 3dev-chrisl2model 4dev-chrisl2msdb 5dev-chrisl2mssqlsystemresource 6dev-chrisl2tempdb 7dev-chrisl2sql2005SqlMonitorData 8dev-chrisl2sql2005TestDatabase 9dev-chrisl2sql2005master 10dev-chrisl2sql2005model 11dev-chrisl2sql2005msdb 12dev-chrisl2sql2005mssqlsystemresource 13dev-chrisl2sql2005tempdb 14dev-chrisl2sql2008SqlMonitorData 15dev-chrisl2sql2008master 16dev-chrisl2sql2008model 17dev-chrisl2sql2008msdb 18dev-chrisl2sql2008mssqlsystemresource 19dev-chrisl2sql2008tempdb These results show that I have three SQL Server instances on my machine (a default instance, one named sql2005 and one named sql2008), and each instance has the usual set of system databases, along with a database named SqlMonitorData. Basically, this is where I test SQL Monitor on different versions of SQL Server, when I’m developing. There are a few important things we can learn from this query: Each _Keys table has a column named Id. This is the primary key. Each _Keys table has a column named ParentId. A foreign key relationship is defined between each _Keys table and its parent _Keys table in the hierarchy. There are two exceptions to this, Cluster_Keys and Group_Keys, because clusters and groups live at the root level of the object hierarchy. Each _Keys table has a column named _Name. This is used to uniquely identify objects in the table within the scope of the same shared parent object. Actually, that last item isn’t always true. In some cases, the _Name column is actually called something else. For example, the data.Cluster_Machine_Services_Keys table has a column named _ServiceName instead of _Name (sorry for the inconsistency). In other cases, a name isn’t sufficient to uniquely identify an object. For example, right now my PC has multiple processes running, all sharing the same name, Chrome (one for each tab open in my web-browser). In such cases, multiple columns are used to uniquely identify an object within the scope of the same shared parent object. Well, that’s it for now. I’ve given you enough information for you to explore the _Keys tables to see how objects are stored in your own data repositories. In a future post, I’ll try to explain how monitoring data is stored for each object, using the _StableSamples and _UnstableSamples tables. If you have any questions about this post, or suggestions for future posts, just submit them in the comments section below.

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• SQL SERVER – Using expressor Composite Types to Enforce Business Rules

  - by pinaldave

  One of the features that distinguish the expressor Data Integration Platform from other products in the data integration space is its concept of composite types, which provide an effective and easily reusable way to clearly define the structure and characteristics of data within your application.  An important feature of the composite type approach is that it allows you to easily adjust the content of a record to its ultimate purpose.  For example, a record used to update a row in a database table is easily defined to include only the minimum set of columns, that is, a value for the key column and values for only those columns that need to be updated. Much like a class in higher level programming languages, you can also use the composite type as a way to enforce business rules onto your data by encapsulating a datum’s name, data type, and constraints (for example, maximum, minimum, or acceptable values) as a single entity, which ensures that your data can not assume an invalid value.  To what extent you use this functionality is a decision you make when designing your application; the expressor design paradigm does not force this approach on you. Let’s take a look at how these features are used.  Suppose you want to create a group of applications that maintain the employee table in your human resources database. Your table might have a structure similar to the HumanResources.Employee table in the AdventureWorks database.  This table includes two columns, EmployeID and rowguid, that are maintained by the relational database management system; you cannot provide values for these columns when inserting new rows into the table. Additionally, there are columns such as VacationHours and SickLeaveHours that you might choose to update for all employees on a monthly basis, which justifies creation of a dedicated application. By creating distinct composite types for the read, insert and update operations against this table, you can more easily manage this table’s content. When developing this application within expressor Studio, your first task is to create a schema artifact for the database table.  This process is completely driven by a wizard, only requiring that you select the desired database schema and table.  The resulting schema artifact defines the mapping of result set records to a record within the expressor data integration application.  The structure of the record within the expressor application is a composite type that is given the default name CompositeType1.  As you can see in the following figure, all columns from the table are included in the result set and mapped to an identically named attribute in the default composite type. If you are developing an application that needs to read this table, perhaps to prepare a year-end report of employees by department, you would probably not be interested in the data in the rowguid and ModifiedDate columns.  A typical approach would be to drop this unwanted data in a downstream operator.  But using an alternative composite type provides a better approach in which the unwanted data never enters your application. While working in expressor  Studio’s schema editor, simply create a second composite type within the same schema artifact, which you could name ReadTable, and remove the attributes corresponding to the unwanted columns. The value of an alternative composite type is even more apparent when you want to insert into or update the table.  In the composite type used to insert rows, remove the attributes corresponding to the EmployeeID primary key and rowguid uniqueidentifier columns since these values are provided by the relational database management system. And to update just the VacationHours and SickLeaveHours columns, use a composite type that includes only the attributes corresponding to the EmployeeID, VacationHours, SickLeaveHours and ModifiedDate columns. By specifying this schema artifact and composite type in a Write Table operator, your upstream application need only deal with the four required attributes and there is no risk of unintentionally overwriting a value in a column that does not need to be updated. Now, what about the option to use the composite type to enforce business rules?  If you review the composition of the default composite type CompositeType1, you will note that the constraints defined for many of the attributes mirror the table column specifications.  For example, the maximum number of characters in the NationaIDNumber, LoginID and Title attributes is equivalent to the maximum width of the target column, and the size of the MaritalStatus and Gender attributes is limited to a single character as required by the table column definition.  If your application code leads to a violation of these constraints, an error will be raised.  The expressor design paradigm then allows you to handle the error in a way suitable for your application.  For example, a string value could be truncated or a numeric value could be rounded. Moreover, you have the option of specifying additional constraints that support business rules unrelated to the table definition. Let’s assume that the only acceptable values for marital status are S, M, and D.  Within the schema editor, double-click on the MaritalStatus attribute to open the Edit Attribute window.  Then click the Allowed Values checkbox and enter the acceptable values into the Constraint Value text box. The schema editor is updated accordingly. There is one more option that the expressor semantic type paradigm supports.  Since the MaritalStatus attribute now clearly specifies how this type of information should be represented (a single character limited to S, M or D), you can convert this attribute definition into a shared type, which will allow you to quickly incorporate this definition into another composite type or into the description of an output record from a transform operator. Again, double-click on the MaritalStatus attribute and in the Edit Attribute window, click Convert, which opens the Share Local Semantic Type window that you use to name this shared type.  There’s no requirement that you give the shared type the same name as the attribute from which it was derived.  You should supply a name that makes it obvious what the shared type represents. In this posting, I’ve overviewed the expressor semantic type paradigm and shown how it can be used to make your application development process more productive.  The beauty of this feature is that you choose when and to what extent you utilize the functionality, but I’m certain that if you opt to follow this approach your efforts will become more efficient and your work will progress more quickly.  As always, I encourage you to download and evaluate expressor Studio for your current and future data integration needs. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: CodeProject, Pinal Dave, PostADay, SQL, SQL Authority, SQL Documentation, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• Differences Between NHibernate and Entity Framework

  - by Ricardo Peres

  Introduction NHibernate and Entity Framework are two of the most popular O/RM frameworks on the .NET world. Although they share some functionality, there are some aspects on which they are quite different. This post will describe this differences and will hopefully help you get started with the one you know less. Mind you, this is a personal selection of features to compare, it is by no way an exhaustive list. History First, a bit of history. NHibernate is an open-source project that was first ported from Java’s venerable Hibernate framework, one of the first O/RM frameworks, but nowadays it is not tied to it, for example, it has .NET specific features, and has evolved in different ways from those of its Java counterpart. Current version is 3.3, with 3.4 on the horizon. It currently targets .NET 3.5, but can be used as well in .NET 4, it only makes no use of any of its specific functionality. You can find its home page at NHForge. Entity Framework 1 came out with .NET 3.5 and is now on its second major version, despite being version 4. Code First sits on top of it and but came separately and will also continue to be released out of line with major .NET distributions. It is currently on version 4.3.1 and version 5 will be released together with .NET Framework 4.5. All versions will target the current version of .NET, at the time of their release. Its home location is located at MSDN. Architecture In NHibernate, there is a separation between the Unit of Work and the configuration and model instances. You start off by creating a Configuration object, where you specify all global NHibernate settings such as the database and dialect to use, the batch sizes, the mappings, etc, then you build an ISessionFactory from it. The ISessionFactory holds model and metadata that is tied to a particular database and to the settings that came from the Configuration object, and, there will typically be only one instance of each in a process. Finally, you create instances of ISession from the ISessionFactory, which is the NHibernate representation of the Unit of Work and Identity Map. This is a lightweight object, it basically opens and closes a database connection as required and keeps track of the entities associated with it. ISession objects are cheap to create and dispose, because all of the model complexity is stored in the ISessionFactory and Configuration objects. As for Entity Framework, the ObjectContext/DbContext holds the configuration, model and acts as the Unit of Work, holding references to all of the known entity instances. This class is therefore not lightweight as its NHibernate counterpart and it is not uncommon to see examples where an instance is cached on a field. Mappings Both NHibernate and Entity Framework (Code First) support the use of POCOs to represent entities, no base classes are required (or even possible, in the case of NHibernate). As for mapping to and from the database, NHibernate supports three types of mappings: XML-based, which have the advantage of not tying the entity classes to a particular O/RM; the XML files can be deployed as files on the file system or as embedded resources in an assembly; Attribute-based, for keeping both the entities and database details on the same place at the expense of polluting the entity classes with NHibernate-specific attributes; Strongly-typed code-based, which allows dynamic creation of the model and strongly typing it, so that if, for example, a property name changes, the mapping will also be updated. Entity Framework can use: Attribute-based (although attributes cannot express all of the available possibilities – for example, cascading); Strongly-typed code mappings. Database Support With NHibernate you can use mostly any database you want, including: SQL Server; SQL Server Compact; SQL Server Azure; Oracle; DB2; PostgreSQL; MySQL; Sybase Adaptive Server/SQL Anywhere; Firebird; SQLLite; Informix; Any through OLE DB; Any through ODBC. Out of the box, Entity Framework only supports SQL Server, but a number of providers exist, both free and commercial, for some of the most used databases, such as Oracle and MySQL. See a list here. Inheritance Strategies Both NHibernate and Entity Framework support the three canonical inheritance strategies: Table Per Type Hierarchy (Single Table Inheritance), Table Per Type (Class Table Inheritance) and Table Per Concrete Type (Concrete Table Inheritance). Associations Regarding associations, both support one to one, one to many and many to many. However, NHibernate offers far more collection types: Bags of entities or values: unordered, possibly with duplicates; Lists of entities or values: ordered, indexed by a number column; Maps of entities or values: indexed by either an entity or any value; Sets of entities or values: unordered, no duplicates; Arrays of entities or values: indexed, immutable. Querying NHibernate exposes several querying APIs: LINQ is probably the most used nowadays, and really does not need to be introduced; Hibernate Query Language (HQL) is a database-agnostic, object-oriented SQL-alike language that exists since NHibernate’s creation and still offers the most advanced querying possibilities; well suited for dynamic queries, even if using string concatenation; Criteria API is an implementation of the Query Object pattern where you create a semi-abstract conceptual representation of the query you wish to execute by means of a class model; also a good choice for dynamic querying; Query Over offers a similar API to Criteria, but using strongly-typed LINQ expressions instead of strings; for this, although more refactor-friendlier that Criteria, it is also less suited for dynamic queries; SQL, including stored procedures, can also be used; Integration with Lucene.NET indexer is available. As for Entity Framework: LINQ to Entities is fully supported, and its implementation is considered very complete; it is the API of choice for most developers; Entity-SQL, HQL’s counterpart, is also an object-oriented, database-independent querying language that can be used for dynamic queries; SQL, of course, is also supported. Caching Both NHibernate and Entity Framework, of course, feature first-level cache. NHibernate also supports a second-level cache, that can be used among multiple ISessionFactorys, even in different processes/machines: Hashtable (in-memory); SysCache (uses ASP.NET as the cache provider); SysCache2 (same as above but with support for SQL Server SQL Dependencies); Prevalence; SharedCache; Memcached; Redis; NCache; Appfabric Caching. Out of the box, Entity Framework does not have any second-level cache mechanism, however, there are some public samples that show how we can add this. ID Generators NHibernate supports different ID generation strategies, coming from the database and otherwise: Identity (for SQL Server, MySQL, and databases who support identity columns); Sequence (for Oracle, PostgreSQL, and others who support sequences); Trigger-based; HiLo; Sequence HiLo (for databases that support sequences); Several GUID flavors, both in GUID as well as in string format; Increment (for single-user uses); Assigned (must know what you’re doing); Sequence-style (either uses an actual sequence or a single-column table); Table of ids; Pooled (similar to HiLo but stores high values in a table); Native (uses whatever mechanism the current database supports, identity or sequence). Entity Framework only supports: Identity generation; GUIDs; Assigned values. Properties NHibernate supports properties of entity types (one to one or many to one), collections (one to many or many to many) as well as scalars and enumerations. It offers a mechanism for having complex property types generated from the database, which even include support for querying. It also supports properties originated from SQL formulas. Entity Framework only supports scalars, entity types and collections. Enumerations support will come in the next version. Events and Interception NHibernate has a very rich event model, that exposes more than 20 events, either for synchronous pre-execution or asynchronous post-execution, including: Pre/Post-Load; Pre/Post-Delete; Pre/Post-Insert; Pre/Post-Update; Pre/Post-Flush. It also features interception of class instancing and SQL generation. As for Entity Framework, only two events exist: ObjectMaterialized (after loading an entity from the database); SavingChanges (before saving changes, which include deleting, inserting and updating). Tracking Changes For NHibernate as well as Entity Framework, all changes are tracked by their respective Unit of Work implementation. Entities can be attached and detached to it, Entity Framework does, however, also support self-tracking entities. Optimistic Concurrency Control NHibernate supports all of the imaginable scenarios: SQL Server’s ROWVERSION; Oracle’s ORA_ROWSCN; A column containing date and time; A column containing a version number; All/dirty columns comparison. Entity Framework is more focused on Entity Framework, so it only supports: SQL Server’s ROWVERSION; Comparing all/some columns. Batching NHibernate has full support for insertion batching, but only if the ID generator in use is not database-based (for example, it cannot be used with Identity), whereas Entity Framework has no batching at all. Cascading Both support cascading for collections and associations: when an entity is deleted, their conceptual children are also deleted. NHibernate also offers the possibility to set the foreign key column on children to NULL instead of removing them. Flushing Changes NHibernate’s ISession has a FlushMode property that can have the following values: Auto: changes are sent to the database when necessary, for example, if there are dirty instances of an entity type, and a query is performed against this entity type, or if the ISession is being disposed; Commit: changes are sent when committing the current transaction; Never: changes are only sent when explicitly calling Flush(). As for Entity Framework, changes have to be explicitly sent through a call to AcceptAllChanges()/SaveChanges(). Lazy Loading NHibernate supports lazy loading for Associated entities (one to one, many to one); Collections (one to many, many to many); Scalar properties (thing of BLOBs or CLOBs). Entity Framework only supports lazy loading for: Associated entities; Collections. Generating and Updating the Database Both NHibernate and Entity Framework Code First (with the Migrations API) allow creating the database model from the mapping and updating it if the mapping changes. Extensibility As you can guess, NHibernate is far more extensible than Entity Framework. Basically, everything can be extended, from ID generation, to LINQ to SQL transformation, HQL native SQL support, custom column types, custom association collections, SQL generation, supported databases, etc. With Entity Framework your options are more limited, at least, because practically no information exists as to what can be extended/changed. It features a provider model that can be extended to support any database. Integration With Other Microsoft APIs and Tools When it comes to integration with Microsoft technologies, it will come as no surprise that Entity Framework offers the best support. For example, the following technologies are fully supported: ASP.NET (through the EntityDataSource); ASP.NET Dynamic Data; WCF Data Services; WCF RIA Services; Visual Studio (through the integrated designer). Documentation This is another point where Entity Framework is superior: NHibernate lacks, for starters, an up to date API reference synchronized with its current version. It does have a community mailing list, blogs and wikis, although not much used. Entity Framework has a number of resources on MSDN and, of course, several forums and discussion groups exist. Conclusion Like I said, this is a personal list. I may come as a surprise to some that Entity Framework is so behind NHibernate in so many aspects, but it is true that NHibernate is much older and, due to its open-source nature, is not tied to product-specific timeframes and can thus evolve much more rapidly. I do like both, and I chose whichever is best for the job I have at hands. I am looking forward to the changes in EF5 which will add significant value to an already interesting product. So, what do you think? Did I forget anything important or is there anything else worth talking about? Looking forward for your comments!

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• Synchronize Data between a Silverlight ListBox and a User Control

  - by psheriff

  One of the great things about XAML is the powerful data-binding capabilities. If you load up a list box with a collection of objects, you can display detail data about each object without writing any C# or VB.NET code. Take a look at Figure 1 that shows a collection of Product objects in a list box. When you click on a list box you bind the current Product object selected in the list box to a set of controls in a user control with just a very simple Binding statement in XAML.  Figure 1: Synchronizing a ListBox to a User Control is easy with Data Binding Product and Products Classes To illustrate this data binding feature I am going to just create some local data instead of using a WCF service. The code below shows a Product class that has three properties, namely, ProductId, ProductName and Price. This class also has a constructor that takes 3 parameters and allows us to set the 3 properties in an instance of our Product class. C#public class Product{  public Product(int productId, string productName, decimal price)  {    ProductId = productId;    ProductName = productName;    Price = price;  }   public int ProductId { get; set; }  public string ProductName { get; set; }  public decimal Price { get; set; }} VBPublic Class Product  Public Sub New(ByVal _productId As Integer, _                 ByVal _productName As String, _                 ByVal _price As Decimal)    ProductId = _productId    ProductName = _productName    Price = _price  End Sub   Private mProductId As Integer  Private mProductName As String  Private mPrice As Decimal   Public Property ProductId() As Integer    Get      Return mProductId    End Get    Set(ByVal value As Integer)      mProductId = value    End Set  End Property   Public Property ProductName() As String    Get      Return mProductName    End Get    Set(ByVal value As String)      mProductName = value    End Set  End Property   Public Property Price() As Decimal    Get      Return mPrice    End Get    Set(ByVal value As Decimal)      mPrice = value    End Set  End PropertyEnd Class To fill up a list box you need a collection class of Product objects. The code below creates a generic collection class of Product objects. In the constructor of the Products class I have hard-coded five product objects and added them to the collection. In a real-world application you would get your data through a call to service to fill the list box, but for simplicity and just to illustrate the data binding, I am going to just hard code the data. C#public class Products : List<Product>{  public Products()  {    this.Add(new Product(1, "Microsoft VS.NET 2008", 1000));    this.Add(new Product(2, "Microsoft VS.NET 2010", 1000));    this.Add(new Product(3, "Microsoft Silverlight 4", 1000));    this.Add(new Product(4, "Fundamentals of N-Tier eBook", 20));    this.Add(new Product(5, "ASP.NET Security eBook", 20));  }} VBPublic Class Products  Inherits List(Of Product)   Public Sub New()    Me.Add(New Product(1, "Microsoft VS.NET 2008", 1000))    Me.Add(New Product(2, "Microsoft VS.NET 2010", 1000))    Me.Add(New Product(3, "Microsoft Silverlight 4", 1000))    Me.Add(New Product(4, "Fundamentals of N-Tier eBook", 20))    Me.Add(New Product(5, "ASP.NET Security eBook", 20))  End SubEnd Class The Product Detail User Control Below is a user control (named ucProduct) that is used to display the product detail information seen in the bottom portion of Figure 1. This is very basic XAML that just creates a text block and a text box control for each of the three properties in the Product class. Notice the {Binding Path=[PropertyName]} on each of the text box controls. This means that if the DataContext property of this user control is set to an instance of a Product class, then the data in the properties of that Product object will be displayed in each of the text boxes. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.ucProduct"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  HorizontalAlignment="Left"  VerticalAlignment="Top">  <Grid Margin="4">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />    </Grid.RowDefinitions>    <Grid.ColumnDefinitions>      <ColumnDefinition MinWidth="120" />      <ColumnDefinition />    </Grid.ColumnDefinitions>    <TextBlock Grid.Row="0"               Grid.Column="0"               Text="Product Id" />    <TextBox Grid.Row="0"             Grid.Column="1"             Text="{Binding Path=ProductId}" />    <TextBlock Grid.Row="1"               Grid.Column="0"               Text="Product Name" />    <TextBox Grid.Row="1"             Grid.Column="1"             Text="{Binding Path=ProductName}" />    <TextBlock Grid.Row="2"               Grid.Column="0"               Text="Price" />    <TextBox Grid.Row="2"             Grid.Column="1"             Text="{Binding Path=Price}" />  </Grid></UserControl> Synchronize ListBox with User Control You are now ready to fill the list box with the collection class of Product objects and then bind the SelectedItem of the list box to the Product detail user control. The XAML below is the complete code for Figure 1. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.MainPage"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS"  VerticalAlignment="Top"  HorizontalAlignment="Left">  <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources>  <Grid x:Name="LayoutRoot"        Margin="4"        Background="White">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="*" />    </Grid.RowDefinitions>    <ListBox x:Name="lstData"             Grid.Row="0"             BorderBrush="Black"             BorderThickness="1"             ItemsSource="{Binding                   Source={StaticResource productCollection}}"             DisplayMemberPath="ProductName" />    <src:ucProduct x:Name="prodDetail"                   Grid.Row="1"                   DataContext="{Binding ElementName=lstData,                                          Path=SelectedItem}" />  </Grid></UserControl> The first step to making this happen is to reference the Silverlight project (SL_SyncListBoxAndUserControl_CS) where the Product and Products classes are located. I added this namespace and assigned it a namespace prefix of “src” as shown in the line below: xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS" Next, to use the data from an instance of the Products collection, you create a UserControl.Resources section in the XAML and add a tag that creates an instance of the Products class and assigns it a key of “productCollection”.   <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources> Next, you bind the list box to this productCollection object using the ItemsSource property. You bind the ItemsSource of the list box to the static resource named productCollection. You can then set the DisplayMemberPath attribute of the list box to any property of the Product class that you want. In the XAML below I used the ProductName property. <ListBox x:Name="lstData"         ItemsSource="{Binding             Source={StaticResource productCollection}}"         DisplayMemberPath="ProductName" /> You now need to create an instance of the ucProduct user contol below the list box. You do this by once again referencing the “src” namespace and typing in the name of the user control. You then set the DataContext property on this user control to a binding. The binding uses the ElementName attribute to bind to the list box name, in this case “lstData”. The Path of the data is SelectedItem. These two attributes together tell Silverlight to bind the DataContext to the selected item of the list box. That selected item is a Product object. So, once this is bound, the bindings on each text box in the user control are updated and display the current product information. <src:ucProduct x:Name="prodDetail"               DataContext="{Binding ElementName=lstData,                                      Path=SelectedItem}" /> Summary Once you understand the basics of data binding in XAML, you eliminate a lot code that is otherwise needed to move data into controls and out of controls back into an object. Connecting two controls together is easy by just binding using the ElementName and Path properties of the Binding markup extension. Another good tip out of this blog is use user controls and set the DataContext of the user control to have all of the data on the user control update through the bindings. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "SL – Synchronize List Box Data with User Control" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

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• Designing for the future

  - by Dennis Vroegop

  User interfaces and user experience design is a fast moving field. It’s something that changes pretty quick: what feels fresh today will look outdated tomorrow. I remember the day I first got a beta version of Windows 95 and I felt swept away by the user interface of the OS. It felt so modern! If I look back now, it feels old. Well, it should: the design is 17 years old which is an eternity in our field. Of course, this is not limited to UI. Same goes for many industries. I want you to think back of the cars that amazed you when you were in your teens (if you are in your teens then this may not apply to you). Didn’t they feel like part of the future? Didn’t you think that this was the ultimate in designs? And aren’t those designs hopelessly outdated today (again, depending on your age, it may just be me)? Let’s review the Win95 design: And let’s compare that to Windows 7: There are so many differences here, I wouldn’t even know where to start explaining them. The general feeling however is one of more usability: studies have shown Windows 7 is much easier to understand for new users than the older versions of Windows did. Of course, experienced Windows users didn’t like it: people are usually afraid of changes and like to stick to what they know. But for new users this was a huge improvement. And that is what UX design is all about: make a product easier to use, with less training required and make users feel more productive. Still, there are areas where this doesn’t hold up. There are plenty examples of designs from the past that are still fresh today. But if you look closely at them, you’ll notice some subtle differences. This differences are what keep the designs fresh. A good example is the signs you’ll find on the road. They haven’t changed much over the years (otherwise people wouldn’t recognize them anymore) but they have been changing gradually to reflect changes in traffic. The same goes for computer interfaces. With each new product or version of a product, the UI and UX is changed gradually. Every now and then however, a bigger change is needed. Just think about the introduction of the Ribbon in Microsoft Office 2007: the whole UI was redesigned. A lot of old users (not in age, but in times of using older versions) didn’t like it a bit, but new users or casual users seem to be more efficient using the product. Which, of course, is exactly the reason behind the changes. I believe that a big engine behind the changes in User Experience design has been the web. In the old days (i.e. before the explosion of the internet) user interface design in Windows applications was limited to choosing the margins between your battleship gray buttons. When the web came along, and especially the web 2.0 where the browsers started to act more and more as application platforms, designers stepped in and made a huge impact. In the browser, they could do whatever they wanted. In the beginning this was limited to the darn blink tag but gradually people really started to think about UX. Even more so: the design of the UI and the whole experience was taken away from the developers and put into the hands of people who knew what they were doing: UX designers. This caused some problems. Everyone who has done a web project in the early 2000’s must have had the same experience: the designers give you a set of Photoshop files and tell you to translate it to HTML. Which, of course, is very hard to do. However, with new tooling and new standards this became much easier. The latest version of HTML and CSS has taken the responsibility for the design away from the developers and placed them in the capable hands of the designers. And that’s where that responsibility belongs, after all, I don’t want a designer to muck around in my c# code just as much as he or she doesn’t want me to poke in the sites style definitions. This change in responsibilities resulted in good looking but more important: better thought out user interfaces in websites. And when websites became more and more interactive, people started to expect the same sort of look and feel from their desktop applications. But that didn’t really happen. Most business applications still have that battleship gray look and feel. Ok, they may use a different color but we’re not talking colors here but usability. Now, you may not be able to read the Dutch captions, but even if you did you wouldn’t understand what was going on. At least, not when you first see it. You have to scan the screen, read all the labels, see how they are related to the other elements on the screen and then figure out what they do. If you’re an experienced user of this application however, this might be a good thing: you know what to do and you get all the information you need in one single screen. But for most applications this isn’t the case. A lot of people only use their computer for a limited time a day (a weird concept for me, but it happens) and need it to get something done and then get on with their lives. For them, a user interface experience like the above isn’t working. (disclaimer: I just picked a screenshot, I am not saying this is bad software but it is an example of about 95% of the Windows applications out there). For the knowledge worker, this isn’t a problem. They use one or two systems and they know exactly what they need to do to achieve their goal. They don’t want any clutter on their screen that distracts them from their task, they just want to be as efficient as possible. When they know the systems they are very productive. The point is, how long does it take to become productive? And: could they be even more productive if the UX was better? Are there things missing that they don’t know about? Are there better ways to achieve what they want to achieve? Also: could a system be designed in such a way that it is not only much more easy to work with but also less tiring? in the example above you need to switch between the keyboard and mouse a lot, something that we now know can be very tiring. The goal of most applications (being client apps or websites on any kind of device) is to provide information. Information is data that when given to the right people, on the right time, in the right place and when it is correct adds value for that person (please, remember that definition: I still hear the statement “the information was wrong” which doesn’t make sense: data can be wrong, information cannot be). So if a system provides data, how can we make sure the chances of becoming information is as high as possible? A good example of a well thought-out system that attempts this is the Zune client. It is a very good application, and I think the UX is much better than it’s main competitor iTunes. Have a look at both: On the left you see the iTunes screenshot, on the right the Zune. As you notice, the Zune screen has more images but less chrome (chrome being visuals not part of the data you want to show, i.e. edges around buttons). The whole thing is text oriented or image oriented, where that text or image is part of the information you need. What is important is big, what’s less important is smaller. Yet, everything you need to know at that point is present and your attention is drawn immediately to what you’re trying to achieve: information about music. You can easily switch between the content on your machine and content on your Zune player but clicking on the image of the player. But if you didn’t know that, you’d find out soon enough: the whole UX is designed in such a way that it invites you to play around. So sooner or later (probably sooner) you’d click on that image and you would see what it does. In the iTunes version it’s harder to find: the discoverability is a lot lower. For inexperienced people the Zune player feels much more natural than the iTunes player, and they get up to speed a lot faster. How does this all work? Why is this UX better? The answer lies in a project from Microsoft with the codename (it seems to be becoming the official name though) “Metro”. Metro is a design language, based on certain principles. When they thought about UX they took a good long look around them and went out in search of metaphors. And they found them. The team noticed that signage in streets, airports, roads, buildings and so on are usually very clear and very precise. These signs give you the information you need and nothing more. It’s simple, clearly understood and fast to understand. A good example are airport signs. Airports can be intimidating places, especially for the non-experienced traveler. In the early 1990’s Amsterdam Airport Schiphol decided to redesign all the signage to make the traveller feel less disoriented. They developed a set of guidelines for signs and implemented those. Soon, most airports around the world adopted these ideas and you see variations of the Dutch signs everywhere on the globe. The signs are text-oriented. Yes, there are icons explaining what it all means for the people who can’t read or don’t understand the language, but the basic sign language is text. It’s clear, it’s high-contrast and it’s easy to understand. One look at the sign and you know where to go. The only thing I don’t like is the green sign pointing to the emergency exit, but since this is the default style for emergency exits I understand why they did this. If you look at the Zune UI again, you’ll notice the similarities. Text oriented, little or no icons, clear usage of fonts and all the information you need. This design language has a set of principles: Clean, light, open and fast Content, not chrome Soulful and alive These are just a couple of the principles, you can read the whole philosophy behind Metro for Windows Phone 7 here. These ideas seem to work. I love my Windows Phone 7. It’s easy to use, it’s clear, there’s no clutter that I do not need. It works for me. And I noticed it works for a lot of other people as well, especially people who aren’t as proficient with computers as I am. You see these ideas in a lot other places. Corning, a manufacturer of glass, has made a video of possible usages of their products. It’s their glimpse into the future. You’ll notice that a lot of the UI in the screens look a lot like what Microsoft is doing with Metro (not coincidentally Corning is the supplier for the Gorilla glass display surface on the new SUR40 device (or Surface v2.0 as a lot of people call it)). The idea behind this vision is that data should be available everywhere where you it. Systems should be available at all times and data is presented in a clear and light manner so that you can turn that data into information. You don’t need a lot of fancy animations that only distract from the data. You want the data and you want it fast. Have a look at this truly inspiring video that made: This is what I believe the future will look like. Of course, not everything is possible, or even desirable. But it is a nice way to think about the future . I feel very strongly about designing applications in such a way that they add value to the user. Designing applications that turn data into information. Applications that make the user feel happy to use them. So… when are you going to drop the battleship-gray designs? Tags van Technorati: surface,design,windows phone 7,wp7,metro

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