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  • Adding data (not only text) to a multi column ListView (WPF)

    - by user811804
    I am working on a WPF application in C# (.NET 4.0) where I have a ListView with a GridView that has two columns. I dynamically want to add rows (in code). My dilemma is that only the first column will have regular text added to it. The second column will have an object that includes a multi column Grid with TextBlocks. (see link http://imageshack.us/photo/my-images/803/listview.png/) If I do what you would normally do when you want to enter text in all columns (ie. DisplayMemberBinding) all I get in the second column is the text "System.Windows.Grid", which obviously isn't what I want. For reference if I just try to add the Grid object (with the TextBlocks) with the code listView1.Items.Add(grid1) (not using DisplayMemberBinding) the object gets added to the second column only (with the first column being blank) and not how it normally works with text where the same text ends up in all columns. I hope my question is detailed enough and any help with this would be much appreciated. EDIT: I have tried the following code, howeever every time I click the button to add a new row every single row gets updated with the same datatemplate. (ie. the second column always shows the same data on every row.) xaml: <Window x:Class="TEST.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Name="AAA" Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded"> <Grid Name="grid1"> <Grid.ColumnDefinitions> <ColumnDefinition Width="374*" /> <ColumnDefinition Width="129*" /> </Grid.ColumnDefinitions> <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="21,12,0,0" Name="button1" VerticalAlignment="Top" Width="75" Grid.Column="1" Click="button1_Click" /> </Grid> code: public partial class MainWindow : Window { ListView listView1 = new ListView(); GridViewColumn viewCol2 = new GridViewColumn(); public MainWindow() { InitializeComponent(); Style style = new Style(typeof(ListViewItem)); style.Setters.Add(new Setter(ListViewItem.HorizontalContentAlignmentProperty, HorizontalAlignment.Stretch)); listView1.ItemContainerStyle = style; GridView gridView1 = new GridView(); listView1.View = gridView1; GridViewColumn viewCol1 = new GridViewColumn(); viewCol1.Header = "Option"; gridView1.Columns.Add(viewCol1); viewCol2.Header = "Value"; gridView1.Columns.Add(viewCol2); grid1.Children.Add(listView1); viewCol1.DisplayMemberBinding = new Binding("Option"); } private void Window_Loaded(object sender, RoutedEventArgs e) { } private void button1_Click(object sender, RoutedEventArgs e) { DataTemplate dataTemplate = new DataTemplate(); FrameworkElementFactory spFactory = new FrameworkElementFactory(typeof(Grid)); Random random = new Random(); int cols = random.Next(1, 6); int full = 100; for (int i = 0; i < cols; i++) { FrameworkElementFactory col1 = new FrameworkElementFactory(typeof(ColumnDefinition)); int partWidth = random.Next(0, full); full -= partWidth; col1.SetValue(ColumnDefinition.WidthProperty, new GridLength(partWidth, GridUnitType.Star)); spFactory.AppendChild(col1); } if (full > 0) { FrameworkElementFactory col1 = new FrameworkElementFactory(typeof(ColumnDefinition)); col1.SetValue(ColumnDefinition.WidthProperty, new GridLength(full, GridUnitType.Star)); spFactory.AppendChild(col1); } for (int i = 0; i < cols; i++) { FrameworkElementFactory text1 = new FrameworkElementFactory(typeof(TextBlock)); SolidColorBrush sb1 = new SolidColorBrush(); switch (i) { case 0: sb1.Color = Colors.Blue; break; case 1: sb1.Color = Colors.Red; break; case 2: sb1.Color = Colors.Yellow; break; case 3: sb1.Color = Colors.Green; break; case 4: sb1.Color = Colors.Purple; break; case 5: sb1.Color = Colors.Pink; break; case 6: sb1.Color = Colors.Brown; break; } text1.SetValue(TextBlock.BackgroundProperty, sb1); text1.SetValue(Grid.ColumnProperty, i); spFactory.AppendChild(text1); } if (full > 0) { FrameworkElementFactory text1 = new FrameworkElementFactory(typeof(TextBlock)); SolidColorBrush sb1 = new SolidColorBrush(Colors.Black); text1.SetValue(TextBlock.BackgroundProperty, sb1); text1.SetValue(Grid.ColumnProperty, cols); spFactory.AppendChild(text1); } dataTemplate.VisualTree = spFactory; viewCol2.CellTemplate = dataTemplate; int rows = listView1.Items.Count + 1; listView1.Items.Add(new { Option = "Row " + rows }); } }

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  • .NET interview, code structure and the design

    - by j_lewis
    I have been given the below .NET question in an interview. I don’t know why I got low marks. Unfortunately I did not get a feedback. Question: The file hockey.csv contains the results from the Hockey Premier League. The columns ‘For’ and ‘Against’ contain the total number of goals scored for and against each team in that season (so Alabama scored 79 goals against opponents, and had 36 goals scored against them). Write a program to print the name of the team with the smallest difference in ‘for’ and ‘against’ goals. the structure of the hockey.csv looks like this (it is a valid csv file, but I just copied the values here to get an idea) Team - For - Against Alabama 79 36 Washinton 67 30 Indiana 87 45 Newcastle 74 52 Florida 53 37 New York 46 47 Sunderland 29 51 Lova 41 64 Nevada 33 63 Boston 30 64 Nevada 33 63 Boston 30 64 Solution: class Program { static void Main(string[] args) { string path = @"C:\Users\<valid csv path>"; var resultEvaluator = new ResultEvaluator(string.Format(@"{0}\{1}",path, "hockey.csv")); var team = resultEvaluator.GetTeamSmallestDifferenceForAgainst(); Console.WriteLine( string.Format("Smallest difference in ‘For’ and ‘Against’ goals > TEAM: {0}, GOALS DIF: {1}", team.Name, team.Difference )); Console.ReadLine(); } } public interface IResultEvaluator { Team GetTeamSmallestDifferenceForAgainst(); } public class ResultEvaluator : IResultEvaluator { private static DataTable leagueDataTable; private readonly string filePath; private readonly ICsvExtractor csvExtractor; public ResultEvaluator(string filePath){ this.filePath = filePath; csvExtractor = new CsvExtractor(); } private DataTable LeagueDataTable{ get { if (leagueDataTable == null) { leagueDataTable = csvExtractor.GetDataTable(filePath); } return leagueDataTable; } } public Team GetTeamSmallestDifferenceForAgainst() { var teams = GetTeams(); var lowestTeam = teams.OrderBy(p => p.Difference).First(); return lowestTeam; } private IEnumerable<Team> GetTeams() { IList<Team> list = new List<Team>(); foreach (DataRow row in LeagueDataTable.Rows) { var name = row["Team"].ToString(); var @for = int.Parse(row["For"].ToString()); var against = int.Parse(row["Against"].ToString()); var team = new Team(name, against, @for); list.Add(team); } return list; } } public interface ICsvExtractor { DataTable GetDataTable(string csvFilePath); } public class CsvExtractor : ICsvExtractor { public DataTable GetDataTable(string csvFilePath) { var lines = File.ReadAllLines(csvFilePath); string[] fields; fields = lines[0].Split(new[] { ',' }); int columns = fields.GetLength(0); var dt = new DataTable(); //always assume 1st row is the column name. for (int i = 0; i < columns; i++) { dt.Columns.Add(fields[i].ToLower(), typeof(string)); } DataRow row; for (int i = 1; i < lines.GetLength(0); i++) { fields = lines[i].Split(new char[] { ',' }); row = dt.NewRow(); for (int f = 0; f < columns; f++) row[f] = fields[f]; dt.Rows.Add(row); } return dt; } } public class Team { public Team(string name, int against, int @for) { Name = name; Against = against; For = @for; } public string Name { get; private set; } public int Against { get; private set; } public int For { get; private set; } public int Difference { get { return (For - Against); } } } Output: Smallest difference in for' andagainst' goals TEAM: Boston, GOALS DIF: -34 Can someone please review my code and see anything obviously wrong here? They were only interested in the structure/design of the code and whether the program produces the correct result (i.e lowest difference). Much appreciated. "P.S - Please correct me if the ".net-interview" tag is not the right tag to use"

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  • Getting UPK data into Excel

    - by maria.cozzolino(at)oracle.com
    Did you ever want someone to review your UPK outline outside of the Developer? You can send your outline to an Excel report, which can be distributed through email. Depending on how much additional data you want with your outline, there are two ways you can do this task. Basic data: • You can print a listing of all the items in the outline. • With your outline open, choose File/Print... • Choose the "Save document as" command on the right, and choose Excel (or xlsx). • HINT: If you have not expanded your entire outline, it's faster to use the commands in Developer to expand the entire outline. However, you can expand specific sections by clicking on them in the print preview. • NOTE: If you have the Details view displayed rather than the Player view, you can print all the data that appears in that view. Advanced data: If you desire a more detailed report, you can use the HP Quality Center publishing style, which also creates an Excel file. This style contains a default set of fields for use with Quality Center, but any of the metadata fields can be added to the report, and it can be used for more than just importing into HP Quality Center. To add additional columns to the HP Quality Center publishing style: 1. Make a copy of the publishing style. This process ensures that you have a good copy to revert to if something goes wrong with your customizations, and also allows you to keep your modifications when the software is upgraded. 2. Open the copy of the columnspec.xml file in your favorite XML editor - I use notepad. (This file is located in a language-specific folder in the HP Quality Center publishing style.) 3. Scroll down the columnspec file until you find the column to include. All the metadata fields that can be added to the report are listed in the columnspec file - you just need to tell the system to include the columns. 4. You will see a series of sections like this: 5. Change the value for "col export" to "yes". This will include the column in the Excel file. 6. If desired, change the value for "Play_ModesColHeader" to be whatever name you wish to appear in the Excel column heading. 7. Save the columnspec file. 8. Save the publishing style package. Now, when you publish for HP Quality Center, you will see your newly added columns. You can refer to the section on Customizing HP Quality Center Output in the Content Deployment Guide for additional customization details. Happy customization! I'd be interested in hearing what other uses you have for Excel reporting. Wishing you and yours a happy and healthy New Year! ~~Maria Cozzolino, Manager of Software Requirements and UI

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  • Floating Panels and Describe Windows in Oracle SQL Developer

    - by thatjeffsmith
    One of the challenges I face as I try to share tips about our software is that I tend to assume there are features that you just ‘know about.’ Either they’re so intuitive that you MUST know about them, or it’s a feature that I’ve been using for so long I forget that others may have never even seen it before. I want to cover two of those today - Describe (DESC) – SHIFT+F4 Floating Panels My super-exciting desktop SQL Developer and Describe DESC or Describe is an Oracle SQL*Plus command. It shows what a table or view is composed of in terms of it’s column definition. Here’s an example: SQL*Plus: Release 11.2.0.3.0 Production on Fri Sep 21 14:25:37 2012 Copyright (c) 1982, 2011, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> desc beer; Name Null? Type ----------------------------------------- -------- ---------------------------- BREWERY NOT NULL VARCHAR2(100) CITY VARCHAR2(100) STATE VARCHAR2(100) COUNTRY VARCHAR2(100) ID NUMBER SQL> You can get the same information – and a good bit more – in SQL Developer using the SQL Developer DESC command. You invoke it with SHIFT+F4. It will open a floating (non-modal!) window with the information you want. Here’s an example: I can see my column definitions, constratins, stats, privs, etc A few ‘cool’ things you should be aware of: I can open as many as I want, and still work in my worksheet, browser, etc. I can also DESC an index, user, or most any other database object I can of course move them off my primary desktop display The DESC panel’s are read-only. I can’t drop a constraint from within the DESC window of a given table. But for dragging columns into my worksheet, and checking out the stats for my objects as I query them – it’s very, very handy. Try This Right Now Type ‘scott.emp’ (or some other table you have), place your cursor on the text, and hit SHIFT+F4. You’ll see the EMP object open. Now click into a column name in the columns page. Drag it into your worksheet. It will paste that column name into your query. This is an alternative for those that don’t like our code insight feature or dragging columns off the connection tree (new for v3.2!) Got it? SQL Developer’s Floating Panels Ok, let’s talk about a similar feature. Did you know that any dockable panel from the View menu can also be ‘floated?’ One of my favorite features is the SQL History. Every query I run is recorded, and I can recall them later without having to remember what I ran and when. And I USUALLY use the keyboard shortcuts for this. Let your trouble float away…if only it were so easy as a right-click in the real world. But sometimes I still want to see my recall list without having to give up my screen real estate. So I just mouse-right click on the panel tab and select ‘Float.’ Then I move it over to my secondary display – see the poorly lit picture in the beginning of this post. And that’s it. Simple, I know. But I thought you should know about these two things!

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  • C# XNA Normals Question

    - by Wade
    Hello all! I have been working on some simple XNA proof of concept for a game idea I have as well as just to further my learning in XNA. However, i seem to be stuck on these dreaded normals, and using the BasicEffect with default lighting i can't seem to tell if my normals are being calculated correctly, hence the question. I'm mainly drawing cubes at the moment, I'm using a triangle list and a VertexBuffer to get the job done. The north face of my cube has two polygons and 6 vectors: Vector3 startPosition = new Vector3(0,0,0); corners[0] = startPosition; // This is the start position. Block size is 5. corners[1] = new Vector3(startPosition.X, startPosition.Y + BLOCK_SIZE, startPosition.Z); corners[2] = new Vector3(startPosition.X + BLOCK_SIZE, startPosition.Y, startPosition.Z); corners[3] = new Vector3(startPosition.X + BLOCK_SIZE, startPosition.Y + BLOCK_SIZE, startPosition.Z); verts[0] = new VertexPositionNormalTexture(corners[0], normals[0], textCoordBR); verts[1] = new VertexPositionNormalTexture(corners[1], normals[0], textCoordTR); verts[2] = new VertexPositionNormalTexture(corners[2], normals[0], textCoordBL); verts[3] = new VertexPositionNormalTexture(corners[3], normals[0], textCoordTL); verts[4] = new VertexPositionNormalTexture(corners[2], normals[0], textCoordBL); verts[5] = new VertexPositionNormalTexture(corners[1], normals[0], textCoordTR); Using those coordinates I want to generate the normal for the north face, I have no clue how to get the average of all those vectors and create a normal for the two polygons that it makes. Here is what i tried: normals[0] = Vector3.Cross(corners[1], corners[2]); normals[0].Normalize(); It seems like its correct, but then using the same thing for other sides of the cube the lighting effect seems weird, and not cohesive with where i think the light source is coming from, not really sure with the BasicEffect. Am I doing this right? Can anyone explain in lay mans terms how normals are calculated. Any help is much appreciated. Note: I tried going through Riemers and such to figure it out with no luck, it seems no one really goes over the math well enough. Thanks!

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  • Architecture strategies for a complex competition scoring system

    - by mikewassmer
    Competition description: There are about 10 teams competing against each other over a 6-week period. Each team's total score (out of a 1000 total available points) is based on the total of its scores in about 25,000 different scoring elements. Most scoring elements are worth a small fraction of a point and there will about 10 X 25,000 = 250,000 total raw input data points. The points for some scoring elements are awarded at frequent regular time intervals during the competition. The points for other scoring elements are awarded at either irregular time intervals or at just one moment in time. There are about 20 different types of scoring elements. Each of the 20 types of scoring elements has a different set of inputs, a different algorithm for calculating the earned score from the raw inputs, and a different number of total available points. The simplest algorithms require one input and one simple calculation. The most complex algorithms consist of hundreds or thousands of raw inputs and a more complicated calculation. Some types of raw inputs are automatically generated. Other types of raw inputs are manually entered. All raw inputs are subject to possible manual retroactive adjustments by competition officials. Primary requirements: The scoring system UI for competitors and other competition followers will show current and historical total team scores, team standings, team scores by scoring element, raw input data (at several levels of aggregation, e.g. daily, weekly, etc.), and other metrics. There will be charts, tables, and other widgets for displaying historical raw data inputs and scores. There will be a quasi-real-time dashboard that will show current scores and raw data inputs. Aggregate scores should be updated/refreshed whenever new raw data inputs arrive or existing raw data inputs are adjusted. There will be a "scorekeeper UI" for manually entering new inputs, manually adjusting existing inputs, and manually adjusting calculated scores. Decisions: Should the scoring calculations be performed on the database layer (T-SQL/SQL Server, in my case) or on the application layer (C#/ASP.NET MVC, in my case)? What are some recommended approaches for calculating updated total team scores whenever new raw inputs arrives? Calculating each of the teams' total scores from scratch every time a new input arrives will probably slow the system to a crawl. I've considered some kind of "diff" approach, but that approach may pose problems for ad-hoc queries and some aggegates. I'm trying draw some sports analogies, but it's tough because most games consist of no more than 20 or 30 scoring elements per game (I'm thinking of a high-scoring baseball game; football and soccer have fewer scoring events per game). Perhaps a financial balance sheet analogy makes more sense because financial "bottom line" calcs may be calculated from 250,000 or more transactions. Should I be making heavy use of caching for this application? Are there any obvious approaches or similar case studies that I may be overlooking?

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  • Generate a merge statement from table structure

    - by Nigel Rivett
    This code generates a merge statement joining on he natural key and checking all other columns to see if they have changed. The full version deals with type 2 processing and an audit trail but this version is useful. Just the insert or update part is handy too. Change the table at the top (spt_values in master in the version) and the join columns for the merge in @nk. The output generated is at the top and the code to run to generate it below. Output merge spt_values a using spt_values b on a.name = b.name and a.number = b.number and a.type = b.type when matched and (1=0 or (a.low b.low) or (a.low is null and b.low is not null) or (a.low is not null and b.low is null) or (a.high b.high) or (a.high is null and b.high is not null) or (a.high is not null and b.high is null) or (a.status b.status) or (a.status is null and b.status is not null) or (a.status is not null and b.status is null) ) then update set low = b.low , high = b.high , status = b.status when not matched by target then insert ( name , number , type , low , high , status ) values ( b.name , b.number , b.type , b.low , b.high , b.status ); Generator set nocount on declare @t varchar(128) = 'spt_values' declare @i int = 0 -- this is the natural key on the table used for the merge statement join declare @nk table (ColName varchar(128)) insert @nk select 'Number' insert @nk select 'Name' insert @nk select 'Type' declare @cols table (seq int, nkseq int, type int, colname varchar(128)) ;with cte as ( select ordinal_position, type = case when columnproperty(object_id(@t), COLUMN_NAME,'IsIdentity') = 1 then 3 when nk.ColName is not null then 1 else 0 end, COLUMN_NAME from information_schema.columns c left join @nk nk on c.column_name = nk.ColName where table_name = @t ) insert @cols (seq, nkseq, type, colname) select ordinal_position, row_number() over (partition by type order by ordinal_position) , type, COLUMN_NAME from cte declare @result table (i int, j int, k int, data varchar(500)) select @i = @i + 1 insert @result (i, data) select @i, 'merge ' + @t + ' a' select @i = @i + 1 insert @result (i, data) select @i, ' using cte b' select @i = @i + 1 insert @result (i, j, data) select @i, nkseq, ' ' + case when nkseq = 1 then 'on' else 'and' end + ' a.' + ColName + ' = b.' + ColName from @cols where type = 1 select @i = @i + 1 insert @result (i, data) select @i, ' when matched and (1=0' select @i = @i + 1 insert @result (i, j, k, data) select @i, seq, 1, ' or (a.' + ColName + ' b.' + ColName + ')' + ' or (a.' + ColName + ' is null and b.' + ColName + ' is not null)' + ' or (a.' + ColName + ' is not null and b.' + ColName + ' is null)' from @cols where type 1 select @i = @i + 1 insert @result (i, data) select @i, ' )' select @i = @i + 1 insert @result (i, data) select @i, ' then update set' select @i = @i + 1 insert @result (i, j, data) select @i, nkseq, ' ' + case when nkseq = 1 then ' ' else ', ' end + colname + ' = b.' + colname from @cols where type = 0 select @i = @i + 1 insert @result (i, data) select @i, ' when not matched by target then insert' select @i = @i + 1 insert @result (i, data) select @i, ' (' select @i = @i + 1 insert @result (i, j, data) select @i, seq, ' ' + case when seq = 1 then ' ' else ', ' end + colname from @cols where type 3 select @i = @i + 1 insert @result (i, data) select @i, ' )' select @i = @i + 1 insert @result (i, data) select @i, ' values' select @i = @i + 1 insert @result (i, data) select @i, ' (' select @i = @i + 1 insert @result (i, j, data) select @i, seq, ' ' + case when seq = 1 then ' ' else ', ' end + 'b.' + colname from @cols where type 3 select @i = @i + 1 insert @result (i, data) select @i, ' );' select data from @result order by i,j,k,data

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  • Benchmarking MySQL Replication with Multi-Threaded Slaves

    - by Mat Keep
    0 0 1 1145 6530 Homework 54 15 7660 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} The objective of this benchmark is to measure the performance improvement achieved when enabling the Multi-Threaded Slave enhancement delivered as a part MySQL 5.6. As the results demonstrate, Multi-Threaded Slaves delivers 5x higher replication performance based on a configuration with 10 databases/schemas. For real-world deployments, higher replication performance directly translates to: · Improved consistency of reads from slaves (i.e. reduced risk of reading "stale" data) · Reduced risk of data loss should the master fail before replicating all events in its binary log (binlog) The multi-threaded slave splits processing between worker threads based on schema, allowing updates to be applied in parallel, rather than sequentially. This delivers benefits to those workloads that isolate application data using databases - e.g. multi-tenant systems deployed in cloud environments. Multi-Threaded Slaves are just one of many enhancements to replication previewed as part of the MySQL 5.6 Development Release, which include: · Global Transaction Identifiers coupled with MySQL utilities for automatic failover / switchover and slave promotion · Crash Safe Slaves and Binlog · Optimized Row Based Replication · Replication Event Checksums · Time Delayed Replication These and many more are discussed in the “MySQL 5.6 Replication: Enabling the Next Generation of Web & Cloud Services” Developer Zone article  Back to the benchmark - details are as follows. Environment The test environment consisted of two Linux servers: · one running the replication master · one running the replication slave. Only the slave was involved in the actual measurements, and was based on the following configuration: - Hardware: Oracle Sun Fire X4170 M2 Server - CPU: 2 sockets, 6 cores with hyper-threading, 2930 MHz. - OS: 64-bit Oracle Enterprise Linux 6.1 - Memory: 48 GB Test Procedure Initial Setup: Two MySQL servers were started on two different hosts, configured as replication master and slave. 10 sysbench schemas were created, each with a single table: CREATE TABLE `sbtest` (    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,    `k` int(10) unsigned NOT NULL DEFAULT '0',    `c` char(120) NOT NULL DEFAULT '',    `pad` char(60) NOT NULL DEFAULT '',    PRIMARY KEY (`id`),    KEY `k` (`k`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 10,000 rows were inserted in each of the 10 tables, for a total of 100,000 rows. When the inserts had replicated to the slave, the slave threads were stopped. The slave data directory was copied to a backup location and the slave threads position in the master binlog noted. 10 sysbench clients, each configured with 10 threads, were spawned at the same time to generate a random schema load against each of the 10 schemas on the master. Each sysbench client executed 10,000 "update key" statements: UPDATE sbtest set k=k+1 WHERE id = <random row> In total, this generated 100,000 update statements to later replicate during the test itself. Test Methodology: The number of slave workers to test with was configured using: SET GLOBAL slave_parallel_workers=<workers> Then the slave IO thread was started and the test waited for all the update queries to be copied over to the relay log on the slave. The benchmark clock was started and then the slave SQL thread was started. The test waited for the slave SQL thread to finish executing the 100k update queries, doing "select master_pos_wait()". When master_pos_wait() returned, the benchmark clock was stopped and the duration calculated. The calculated duration from the benchmark clock should be close to the time it took for the SQL thread to execute the 100,000 update queries. The 100k queries divided by this duration gave the benchmark metric, reported as Queries Per Second (QPS). Test Reset: The test-reset cycle was implemented as follows: · the slave was stopped · the slave data directory replaced with the previous backup · the slave restarted with the slave threads replication pointer repositioned to the point before the update queries in the binlog. The test could then be repeated with identical set of queries but a different number of slave worker threads, enabling a fair comparison. The Test-Reset cycle was repeated 3 times for 0-24 number of workers and the QPS metric calculated and averaged for each worker count. MySQL Configuration The relevant configuration settings used for MySQL are as follows: binlog-format=STATEMENT relay-log-info-repository=TABLE master-info-repository=TABLE As described in the test procedure, the slave_parallel_workers setting was modified as part of the test logic. The consequence of changing this setting is: 0 worker threads:    - current (i.e. single threaded) sequential mode    - 1 x IO thread and 1 x SQL thread    - SQL thread both reads and executes the events 1 worker thread:    - sequential mode    - 1 x IO thread, 1 x Coordinator SQL thread and 1 x Worker thread    - coordinator reads the event and hands it to the worker who executes 2+ worker threads:    - parallel execution    - 1 x IO thread, 1 x Coordinator SQL thread and 2+ Worker threads    - coordinator reads events and hands them to the workers who execute them Results Figure 1 below shows that Multi-Threaded Slaves deliver ~5x higher replication performance when configured with 10 worker threads, with the load evenly distributed across our 10 x schemas. This result is compared to the current replication implementation which is based on a single SQL thread only (i.e. zero worker threads). Figure 1: 5x Higher Performance with Multi-Threaded Slaves The following figure shows more detailed results, with QPS sampled and reported as the worker threads are incremented. The raw numbers behind this graph are reported in the Appendix section of this post. Figure 2: Detailed Results As the results above show, the configuration does not scale noticably from 5 to 9 worker threads. When configured with 10 worker threads however, scalability increases significantly. The conclusion therefore is that it is desirable to configure the same number of worker threads as schemas. Other conclusions from the results: · Running with 1 worker compared to zero workers just introduces overhead without the benefit of parallel execution. · As expected, having more workers than schemas adds no visible benefit. Aside from what is shown in the results above, testing also demonstrated that the following settings had a very positive effect on slave performance: relay-log-info-repository=TABLE master-info-repository=TABLE For 5+ workers, it was up to 2.3 times as fast to run with TABLE compared to FILE. Conclusion As the results demonstrate, Multi-Threaded Slaves deliver significant performance increases to MySQL replication when handling multiple schemas. This, and the other replication enhancements introduced in MySQL 5.6 are fully available for you to download and evaluate now from the MySQL Developer site (select Development Release tab). You can learn more about MySQL 5.6 from the documentation  Please don’t hesitate to comment on this or other replication blogs with feedback and questions. Appendix – Detailed Results

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  • How do I use setFilmSize in panda3d to achieve the correct view?

    - by lhk
    I'm working with Panda3d and recently switched my game to isometric rendering. I moved the virtual camera accordingly and set an orthographic lens. Then I implemented the classes "Map" and "Canvas". A canvas is a dynamically generated mesh: a flat quad. I'm using it to render the ingame graphics. Since the game itself is still set in a 3d coordinate system I'm planning to rely on these canvases to draw sprites. I could have named this class "Tile" but as I'd like to use it for non-tile sketches (enemies, environment) as well I thought canvas would describe it's function better. Map does exactly what it's name suggests. Its constructor receives the number of rows and columns and then creates a standard isometric map. It uses the canvas class for tiles. I'm planning to write a map importer that reads a file to create maps on the fly. Here's the canvas implementation: class Canvas: def __init__(self, texture, vertical=False, width=1,height=1): # create the mesh format=GeomVertexFormat.getV3t2() format = GeomVertexFormat.registerFormat(format) vdata=GeomVertexData("node-vertices", format, Geom.UHStatic) vertex = GeomVertexWriter(vdata, 'vertex') texcoord = GeomVertexWriter(vdata, 'texcoord') # add the vertices for a flat quad vertex.addData3f(1, 0, 0) texcoord.addData2f(1, 0) vertex.addData3f(1, 1, 0) texcoord.addData2f(1, 1) vertex.addData3f(0, 1, 0) texcoord.addData2f(0, 1) vertex.addData3f(0, 0, 0) texcoord.addData2f(0, 0) prim = GeomTriangles(Geom.UHStatic) prim.addVertices(0, 1, 2) prim.addVertices(2, 3, 0) self.geom = Geom(vdata) self.geom.addPrimitive(prim) self.node = GeomNode('node') self.node.addGeom(self.geom) # this is the handle for the canvas self.nodePath=NodePath(self.node) self.nodePath.setSx(width) self.nodePath.setSy(height) if vertical: self.nodePath.setP(90) # the most important part: "Drawing" the image self.texture=loader.loadTexture(""+texture+".png") self.nodePath.setTexture(self.texture) Now the code for the Map class class Map: def __init__(self,rows,columns,size): self.grid=[] for i in range(rows): self.grid.append([]) for j in range(columns): # create a canvas for the tile. For testing the texture is preset tile=Canvas(texture="../assets/textures/flat_concrete",width=size,height=size) x=(i-1)*size y=(j-1)*size # set the tile up for rendering tile.nodePath.reparentTo(render) tile.nodePath.setX(x) tile.nodePath.setY(y) # and store it for later access self.grid[i].append(tile) And finally the usage def loadMap(self): self.map=Map(10, 10, 1) this function is called within the constructor of the World class. The instantiation of world is the entry point to the execution. The code is pretty straightforward and runs good. Sadly the output is not as expected: Please note: The problem is not the white rectangle, it's my player object. The problem is that although the map should have equal width and height it's stretched weirdly. With orthographic rendering I expected the map to be a perfect square. What did I do wrong ? UPDATE: I've changed the viewport. This is how I set up the orthographic camera: lens = OrthographicLens() lens.setFilmSize(40, 20) base.cam.node().setLens(lens) You can change the "aspect" by modifying the parameters of setFilmSize. I don't know exactly how they are related to window size and screen resolution but after testing a little the values above seem to work for me. Now everything is rendered correctly as long as I don't resize the window. Every change of the window's size as well as switching to fullscreen destroys the correct rendering. I know that implementing a listener for resize events is not in the scope of this question. However I wonder why I need to make the Film's height two times bigger than its width. My window is quadratic ! Can you tell me how to find out correct setting for the FilmSize ? UPDATE 2: I can imagine that it's hard to envision the behaviour of the game. At first glance the obvious solution is to pass the window's width and height in pixels to setFilmSize. There are two problems with that approach. The parameters for setFilmSize are ingame units. You'll get a way to big view if you pass the pixel size For some strange reason the image is distorted if you pass equal values for width and height. Here's the output for setFilmSize(800,800) You'll have to stress your eyes but you'll see what I mean

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  • Beware of SQL Server and PerfMon differences in disk latency calculation

    - by Michael Zilberstein
    Recently sp_blitz procedure on one of my OLTP servers returned alarming notification about high latency on one of the disks (more than 100ms per IO). Our chief storage guy didn’t understand what I was talking about – according to his measures, average latency is only about 15ms. In order to investigate the issue, I’ve recorded 2 snapshots of sys.dm_io_virtual_file_stats and calculated latency per read and write separately. Results appeared to be even more alarming: while for read average latency...(read more)

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  • Height Map Mapping to "Chunked" Quadrilateralized Spherical Cube

    - by user3684950
    I have been working on a procedural spherical terrain generator for a few months which has a quadtree LOD system. The system splits the six faces of a quadrilateralized spherical cube into smaller "quads" or "patches" as the player approaches those faces. What I can't figure out is how to generate height maps for these patches. To generate the heights I am using a 3D ridged multi fractals algorithm. For now I can only displace the vertices of the patches directly using the output from the ridged multi fractals. I don't understand how I generate height maps that allow the vertices of a terrain patch to be mapped to pixels in the height map. The only thing I can think of is taking each vertex in a patch, plug that into the RMF and take that position and translate into u,v coordinates then determine the pixel position directly from the u,v coordinates and determine the grayscale color based on the height. I feel as if this is the right approach but there are a few other things that may further complicate my problem. First of all I intend to use "height maps" with a pixel resolution of 192x192 while the vertex "resolution" of each terrain patch is only 16x16 - meaning that I don't have any vertices to sample for the RMF for most of the pixels. The main reason the height map resolution is higher so that I can use it to generate a normal map (otherwise the height maps serve little purpose as I can just directly displace vertices as I currently am). I am pretty much following this paper very closely. This is, essentially, the part I am having trouble with. Using the cube-to-sphere mapping and the ridged multifractal algorithm previously described, a normalized height value ([0, 1]) is calculated. Using this height value, the terrain position is calculated and stored in the first three channels of the positionmap (RGB) – this will be used to calculate the normalmap. The fourth channel (A) is used to store the height value itself, to be used in the heightmap. The steps in the first sentence are my primary problem. I don't understand how the pixel positions correspond to positions on the sphere and what positions are sampled for the RMF to generate the pixels if only vertices cannot be used.

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  • Tweaking AStar to find closest location to unreachable destination

    - by Shivan Dragon
    I've implemented AStar in Java and it works ok for an area with obstacles where the chosen destination is reachable. However, when the destination is unreachable, the calculated "path" is in no way to the closest location (to the unreachable location) but is instead some random path. Is there a feasible way to tweak AStar into finding the path to the closest location to an unreachable destination?

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  • Detect Unicode Usage in SQL Column

    One optimization you can make to a SQL table that is overly large is to change from nvarchar (or nchar) to varchar (or char).  Doing so will cut the size used by the data in half, from 2 bytes per character (+ 2 bytes of overhead for varchar) to only 1 byte per character.  However, you will lose the ability to store Unicode characters, such as those used by many non-English alphabets.  If the tables are storing user-input, and your application is or might one day be used internationally, its likely that using Unicode for your characters is a good thing.  However, if instead the data is being generated by your application itself or your development team (such as lookup data), and you can be certain that Unicode character sets are not required, then switching such columns to varchar/char can be an easy improvement to make. Avoid Premature Optimization If you are working with a lookup table that has a small number of rows, and is only ever referenced in the application by its numeric ID column, then you wont see any benefit to using varchar vs. nvarchar.  More generally, for small tables, you wont see any significant benefit.  Thus, if you have a general policy in place to use nvarchar/nchar because it offers more flexibility, do not take this post as a recommendation to go against this policy anywhere you can.  You really only want to act on measurable evidence that suggests that using Unicode is resulting in a problem, and that you wont lose anything by switching to varchar/char. Obviously the main reason to make this change is to reduce the amount of space required by each row.  This in turn affects how many rows SQL Server can page through at a time, and can also impact index size and how much disk I/O is required to respond to queries, etc.  If for example you have a table with 100 million records in it and this table has a column of type nchar(5), this column will use 5 * 2 = 10 bytes per row, and with 100M rows that works out to 10 bytes * 100 million = 1000 MBytes or 1GB.  If it turns out that this column only ever stores ASCII characters, then changing it to char(5) would reduce this to 5*1 = 5 bytes per row, and only 500MB.  Of course, if it turns out that it only ever stores the values true and false then you could go further and replace it with a bit data type which uses only 1 byte per row (100MB  total). Detecting Whether Unicode Is In Use So by now you think that you have a problem and that it might be alleviated by switching some columns from nvarchar/nchar to varchar/char but youre not sure whether youre currently using Unicode in these columns.  By definition, you should only be thinking about this for a column that has a lot of rows in it, since the benefits just arent there for a small table, so you cant just eyeball it and look for any non-ASCII characters.  Instead, you need a query.  Its actually very simple: SELECT DISTINCT(CategoryName)FROM CategoriesWHERE CategoryName <> CONVERT(varchar, CategoryName) Summary Gregg Stark for the tip. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • getting bone base and tip positions from a transform matrix?

    - by ddos
    I need this for a Blender3d script, but you don't really need to know Blender to answer this. I need to get bone head and tip positions from a transform matrix read from a file. The position of base is the location part of the matrix, length of the bone (distance from base to tip) is the scale, position of the tip is calculated from the scale (distance from bone base) and rotation part of the matrix. So how to calculate these? bone.base([x,y,z]) # x,y,z - floats bone.tip([x,y,z])

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  • How to move a directional light according to the camera movement?

    - by Andrea Benedetti
    Given a light direction, how can I move it according to the camera movement, in a shader? Think that an artist has setup a scene (e.g., in 3DSMax) with a mesh in center of that and a directional light with a position and a target. From this position and target I've calculated the light direction. Now I want to use the same direction in my lighting equation but, obviously, I want that this light moves correctly with the camera. Thanks.

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  • What different ways are there to model restitution in a physics engine?

    - by Mikael Högström
    In my physics engine I give a body a value for restitution between 0 and 1. When two bodies collide there seems to be different views on how the restitution of the collision should be calculated. To me the most intuitive seems to be to take the average of the two but some seem to take only the largest one. Are there other ways to do it? Also, could the closing velocity or some other parameter come into effect?

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  • Path tables or real time searching for AI?

    - by SirYakalot
    What is the more common practice in commercial games; path lookup tables or real time searches? I've read that in many games path lookup tables are pre-calculated and baked into each map, so to speak, then steering behaviour is used to handle dynamic obstacles. or is it better practice to use optimised hierarchical A* searches? I understand the pro's and cons of each, I'm just curious as to what is most often used in the industry.

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  • Can't save data for a member in a data form

    - by RahulS
    Implied sharing is an old thing everyone knows the reasons and solutions of that, still little theory about that: With Essbase implied sharing, some members are shared even if you do not explicitly set them as shared. These members are implied shared members. When an implied share relationship is created, each implied member assumes the other member’s value. Essbase assumes (or implies) a shared member relationship in these situations: 1. A parent has only one child 2. A parent has only one child that consolidates to the parent In a Planning form that contains members with an implied sharing relationship, when a value is added for the parent, the child assumes the same value after the form is saved. Likewise, if a value is added for the child, the parent usually assumes the same value after a form is saved.For example, when a calculation script or load rule populates an implied share member, the other implied share member assumes the value of the member populated by the calculation script or load rule. The last value calculated or imported takes precedence. The result is the same whether you refer to the parent or the child as a variable in a calculation script. For more information have a look at: http://docs.oracle.com/cd/E17236_01/epm.1112/hp_admin_11122/ch14s11.html Now the issue which we are going to talk about is We loose data on save even when the parent is dynamic calc and has a single child. A dynamic calc parent to a single child:  If we design the form with following selection: In the data form we will find parent below the member and this is by design whenever you make a selection using commands to select all the member below parent, always children will appear before the parent: Lets try to enter data, Save it Now, try to change the way we selected members Here we go: Now the question again why this behavior: 1. Data from Planning data form passes to Essbase row by row, 2. Because in data form the child member appears before the parent, 3. First, data goes to Essbase for child (SingleStoreChild), 4. Then when Planning passes the data for parent there was #Missing or No data,  5. Over writes the data to #missing. PS: As we know that dynamic calc members are calculated on the fly they are not allocated with any memory in the Essbase, here the parent was dynamic calc and it was pointing to same memory as child in the background, when Planning was passing data to Essbase for second row it has updated the child with missing data.(Little confusing, let me know if you need more explanation) 6. As one of the solutions just change the order of appearance of parent and child. Cheers..!!! Rahul S. https://www.facebook.com/pages/HyperionPlanning/117320818374228

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  • Controlling soft errors and false alarms in SSIS

    - by Jim Giercyk
    If you are like me, you dread the 3AM wake-up call.  I would say that the majority of the pages I get are false alarms.  The alerts that require action often require me to open an SSIS package, see where the trouble is and try to identify the offending data.  That can be very time-consuming and can take quite a chunk out of my beauty sleep.  For those reasons, I have developed a simple error handling scenario for SSIS which allows me to rest a little easier.  Let me first say, this is a high level discussion; getting into the nuts and bolts of creating each shape is outside the scope of this document, but if you have an average understanding of SSIS, you should have no problem following along. In the Data Flow above you can see that there is a caution triangle.  For the purpose of this discussion I am creating a truncation error to demonstrate the process, so this is to be expected.  The first thing we need to do is to redirect the error output.  Double-clicking on the Query shape presents us with the properties window for the input.  Simply set the columns that you want to redirect to Redirect Row in the dropdown box and hit Apply. Without going into a dissertation on error handling, I will just note that you can decide which errors you want to redirect on Error and on Truncation.  Therefore, to override this process for a column or condition, simply do not redirect that column or condition. The next thing we want to do is to add some information about the error; specifically, the name of the package which encountered the error and which step in the package wrote the record to the error table.  REMEMBER: If you redirect the error output, your package will not fail, so you will not know where the error record was created without some additional information.    I added 3 columns to my error record; Severity, Package Name and Step Name.  Severity is just a free-form column that you can use to note whether an error is fatal, whether the package is part of a test job and should be ignored, etc.  Package Name and Step Name are system variables. In my package I have created a truncation situation, where the firstname column is 50 characters in the input, but only 4 characters in the output.  Some records will pass without truncation, others will be sent to the error output.  However, the package will not fail. We can see that of the 14 input rows, 8 were redirected to the error table. This information can be used by another step or another scheduled process or triggered to determine whether an error should be sent.  It can also be used as a historical record of the errors that are encountered over time.  There are other system variables that might make more sense in your infrastructure, so try different things.  Date and time seem like something you would want in your output for example.  In summary, we have redirected the error output from an input, added derived columns with information about the errors, and inserted the information and the offending data into an error table.  The error table information can be used by another step or process to determine, based on the error information, what level alert must be sent.  This will eliminate false alarms, and give you a head start when a genuine error occurs.

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  • design a model for a system of dependent variables

    - by dbaseman
    I'm dealing with a modeling system (financial) that has dozens of variables. Some of the variables are independent, and function as inputs to the system; most of them are calculated from other variables (independent and calculated) in the system. What I'm looking for is a clean, elegant way to: define the function of each dependent variable in the system trigger a re-calculation, whenever a variable changes, of the variables that depend on it A naive way to do this would be to write a single class that implements INotifyPropertyChanged, and uses a massive case statement that lists out all the variable names x1, x2, ... xn on which others depend, and, whenever a variable xi changes, triggers a recalculation of each of that variable's dependencies. I feel that this naive approach is flawed, and that there must be a cleaner way. I started down the path of defining a CalculationManager<TModel> class, which would be used (in a simple example) something like as follows: public class Model : INotifyPropertyChanged { private CalculationManager<Model> _calculationManager = new CalculationManager<Model>(); // each setter triggers a "PropertyChanged" event public double? Height { get; set; } public double? Weight { get; set; } public double? BMI { get; set; } public Model() { _calculationManager.DefineDependency<double?>( forProperty: model => model.BMI, usingCalculation: (height, weight) => weight / Math.Pow(height, 2), withInputs: model => model.Height, model.Weight); } // INotifyPropertyChanged implementation here } I won't reproduce CalculationManager<TModel> here, but the basic idea is that it sets up a dependency map, listens for PropertyChanged events, and updates dependent properties as needed. I still feel that I'm missing something major here, and that this isn't the right approach: the (mis)use of INotifyPropertyChanged seems to me like a code smell the withInputs parameter is defined as params Expression<Func<TModel, T>>[] args, which means that the argument list of usingCalculation is not checked at compile time the argument list (weight, height) is redundantly defined in both usingCalculation and withInputs I am sure that this kind of system of dependent variables must be common in computational mathematics, physics, finance, and other fields. Does someone know of an established set of ideas that deal with what I'm grasping at here? Would this be a suitable application for a functional language like F#? Edit More context: The model currently exists in an Excel spreadsheet, and is being migrated to a C# application. It is run on-demand, and the variables can be modified by the user from the application's UI. Its purpose is to retrieve variables that the business is interested in, given current inputs from the markets, and model parameters set by the business.

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  • google analytics - real-time user stats vs audience overview user stats

    - by udog
    When looking at the real-time analytics reporting for our app, it shows around 150-180 users, say around 10AM (our peak usage time). When I look at the Audience Overview report for the same day (hourly breakdown), the number of users shown for the 10AM hour is over 1000. I'm sure this has to do with some sort of aggregation, but I would like to know more about how these two numbers are calculated in order to understand it.

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  • Pseudo-magnet implementation with chipmunk

    - by Eimantas
    How should I go about implementing "natural" magnet on a certain body in chipmunk space? Context is of simple bodies lying in the space (think chessboard). When one of the figures is activated as a magnet - others should start moving towards it. Currently I'm applying force (cpBodyApplyForce)to the other figures with vector calculated towards the activated figure. However this doesn't really feel "natural". Are there any known algorithms for imitating magnets?

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  • How far should an entity take care of its properties values by itself?

    - by Kharlos Dominguez
    Let's consider the following example of a class, which is an entity that I'm using through Entity Framework. - InvoiceHeader - BilledAmount (property, decimal) - PaidAmount (property, decimal) - Balance (property, decimal) I'm trying to find the best approach to keep Balance updated, based on the values of the two other properties (BilledAmount and PaidAmount). I'm torn between two practices here: Updating the balance amount every time BilledAmount and PaidAmount are updated (through their setters) Having a UpdateBalance() method that the callers would run on the object when appropriate. I am aware that I can just calculate the Balance in its getter. However, it isn't really possible because this is an entity field that needs to be saved back to the database, where it has an actual column, and where the calculated amount should be persisted to. My other worry about the automatically updating approach is that the calculated values might be a little bit different from what was originally saved to the database, due to rounding values (an older version of the software, was using floats, but now decimals). So, loading, let's say 2000 entities from the database could change their status and make the ORM believe that they have changed and be persisted back to the database the next time the SaveChanges() method is called on the context. It would trigger a mass of updates that I am not really interested in, or could cause problems, if the calculation methods changed (the entities fetched would lose their old values to be replaced by freshly recalculated ones, simply by being loaded). Then, let's take the example even further. Each invoice has some related invoice details, which also have BilledAmount, PaidAmount and Balance (I'm simplifying my actual business case for the sake of the example, so let's assume the customer can pay each item of the invoice separately rather than as a whole). If we consider the entity should take care of itself, any change of the child details should cause the Invoice totals to change as well. In a fully automated approach, a simple implementation would be looping through each detail of the invoice to recalculate the header totals, every time one the property changes. It probably would be fine for just a record, but if a lot of entities were fetched at once, it could create a significant overhead, as it would perform this process every time a new invoice detail record is fetched. Possibly worse, if the details are not already loaded, it could cause the ORM to lazy-load them, just to recalculate the balances. So far, I went with the Update() method-way, mainly for the reasons I explained above, but I wonder if it was right. I'm noticing I have to keep calling these methods quite often and at different places in my code and it is potential source of bugs. It also has a detrimental effect on data-binding because when the properties of the detail or header changes, the other properties are left out of date and the method has no way to be called. What is the recommended approach in this case?

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  • How to make an object fly out of a slingshot?

    - by Deza
    At the moment I'm improvising a slingshot, the user can click and drag the projectile and let go. The force on the object is calculated by getting the distance between the vector of the slingshots two forks and the vector between where the user pulled it. However this will always result in a positive number and will not take into account the angle of the object relative to that of the slingshot. How can I make it fly out of the slingshot correctly?

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