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  • How to approach performance issues?

    - by jess
    Hi, We are developing a client-server desktop application(winforms with sql server 2008, using LINQ-SQL).We are now finding many issues related to performance.These relate to querying too much data with LINQ , bad database design,not much caching etc.What do you suggest,we should do - how to go about solving these performance issues? One thing,I am doing is doing sql profiling,and trying to fix some queries.As far caching is concerned,we have static lists.But,how to keep them updated,we don't have any server side implementation.So,these lists can be stale,if someone changes data. regards

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  • c#: Design advice. Using DataTable or List<MyObject> for a generic rule checker

    - by Andrew White
    Hi, I have about 100,000 lines of generic data. Columns/Properties of this data are user definable and are of the usual data types (string, int, double, date). There will be about 50 columns/properties. I have 2 needs: To be able to calculate new columns/properties using an expression e.g. Column3 = Column1 * Column2. Ultimately I would like to be able to use external data using a callback, e.g. Column3 = Column1 * GetTemperature The expression is relatively simple, maths operations, sum, count & IF are the only necessary functions. To be able to filter/group the data and perform aggregations e.g. Sum(Data.Column1) Where(Data.Column2 == "blah") As far as I can see I have two options: 1. Using a DataTable. = Point 1 above is achieved by using DataColumn.Expression = Point 2 above is acheived by using DataTable.DefaultView.RowFilter & C# code 2. Using a List of generic Objects each with a Dictionary< string, object to store the values. = Point 1 could be achieved by something like NCalc = Point 2 is achieved using LINQ DataTable: Pros: DataColumn.Expression is inbuilt Cons: RowFilter & coding c# is not as "nice" as LINQ, DataColumn.Expression does not support callbacks(?) = workaround could be to get & replace external value when creating the calculated column GenericList: Pros: LINQ syntax, NCalc supports callbacks Cons: Implementing NCalc/generic calc engine Based on the above I would think a GenericList approach would win, but something I have not factored in is the performance which for some reason I think would be better with a datatable. Does anyone have a gut feeling / experience with LINQ vs. DataTable performance? How about NCalc? As I said there are about 100,000 rows of data, with 50 columns, of which maybe 20 are calculated. In total about 50 rules will be run against the data, so in total there will be 5 million row/object scans. Would really appreciate any insights. Thx. ps. Of course using a database + SQL & Views etc. would be the easiest solution, but for various reasons can't be implemented.

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  • Rewrite SQL Fulltext Function to return Table only

    - by Alex
    I have a MS SQL Fulltext Function like this: (...) RETURNS TABLE AS RETURN SELECT * FROM fishes INNER JOIN CONTAINSTABLE(fishes, *, @keywords, @limit) AS KEY_TBL ON fishes.id = KEY_TBL.[KEY] When I use this function in LINQ, it generates a special return type which includes all fields of my "fishes" table, plus Key and Rank. How could I rewrite above query, or change something in LINQ, to omit Key and Rank and just return my "fishes" results (and to have the fulltext search result objects be of type Fish, which is what I really care about, so I don't have to cast)?

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  • How do I get results from a link query in the order of IDs that I provide?

    - by Keltex
    I'm looking to get query results back from Linq in the order that I pass IDs to the query. So it would look something like this: var IDs = new int [] { 5, 20, 10 } var items = from mytable in db.MyTable where IDs.Contains(mytable.mytableID) orderby // not sure what to do here select mytable; I'm hoping to get items in the order of IDs (5, 20, 10). (Note this is similar to this question, but I would like to do it in Linq instead of SQL)

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  • Is opening too many datacontexts bad?

    - by ryudice
    I've been checking my application with linq 2 sql profiler, and I noticed that it opens a lot of datacontexts, most of them are opened by the linq datasource I used, since my repositories use only the instance stored in Request.Items, is it bad to open too many datacontext? and how can I make my linqdatasource to use the datacontext that I store in Request.Items for the duration of the request? thanks for any help!

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  • Helping linqtosql datacontext use implicit conversion between varchar column in the database and tab

    - by user213256
    I am creating an mssql database table, "Orders", that will contain a varchar(50) field, "Value" containing a string that represents a slightly complex data type, "OrderValue". I am using a linqtosql datacontext class, which automatically types the "Value" column as a string. I gave the "OrderValue" class implicit conversion operators to and from a string, so I can easily use implicit conversion with the linqtosql classes like this: // get an order from the orders table MyDataContext db = new MyDataContext(); Order order = db.Orders(o => o.id == 1); // use implicit converstion to turn the string representation of the order // value into the complex data type. OrderValue value = order.Value; // adjust one of the fields in the complex data type value.Shipping += 10; // use implicit conversion to store the string representation of the complex // data type back in the linqtosql order object order.Value = value; // save changes db.SubmitChanges(); However, I would really like to be able to tell the linqtosql class to type this field as "OrderValue" rather than as "string". Then I would be able to avoid complex code and re-write the above as: // get an order from the orders table MyDataContext db = new MyDataContext(); Order order = db.Orders(o => o.id == 1); // The Value field is already typed as the "OrderValue" type rather than as string. // When a string value was read from the database table, it was implicity converted // to "OrderValue" type. order.Value.Shipping += 10; // save changes db.SubmitChanges(); In order to achieve this desired goal, I looked at the datacontext designer and selected the "Value" field of the "Order" table. Then, in properties, I changed "Type" to "global::MyApplication.OrderValue". The "Server Data Type" property was left as "VarChar(50) NOT NULL" The project built without errors. However, when reading from the database table, I was presented with the following error message: Could not convert from type 'System.String' to type 'MyApplication.OrderValue'. at System.Data.Linq.DBConvert.ChangeType(Object value, Type type) at Read_Order(ObjectMaterializer1 ) at System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader2.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Example.OrdersProvider.GetOrders() at ... etc From the stack trace, I believe this error is happening while reading the data from the table. When presented with converting a string to my custom data type, even though the implicit conversion operators are present, the DBConvert class gets confused and throws an error. Is there anything I can do to help it not get confused and do the implicit conversion? Thanks in advance, and apologies if I have posted in the wrong forum. cheers / Ben

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  • Intersection() and Except() is too slow with large collections of custom objects

    - by Theo
    I am importing data from another database. My process is importing data from a remote DB into a List<DataModel> named remoteData and also importing data from the local DB into a List<DataModel> named localData. I am then using LINQ to create a list of records that are different so that I can update the local DB to match the data pulled from remote DB. Like this: var outdatedData = this.localData.Intersect(this.remoteData, new OutdatedDataComparer()).ToList(); I am then using LINQ to create a list of records that no longer exist in remoteData, but do exist in localData, so that I delete them from local database. Like this: var oldData = this.localData.Except(this.remoteData, new MatchingDataComparer()).ToList(); I am then using LINQ to do the opposite of the above to add the new data to the local database. Like this: var newData = this.remoteData.Except(this.localData, new MatchingDataComparer()).ToList(); Each collection imports about 70k records, and each of the 3 LINQ operation take between 5 - 10 minutes to complete. How can I make this faster? Here is the object the collections are using: internal class DataModel { public string Key1{ get; set; } public string Key2{ get; set; } public string Value1{ get; set; } public string Value2{ get; set; } public byte? Value3{ get; set; } } The comparer used to check for outdated records: class OutdatedDataComparer : IEqualityComparer<DataModel> { public bool Equals(DataModel x, DataModel y) { var e = string.Equals(x.Key1, y.Key1) && string.Equals(x.Key2, y.Key2) && ( !string.Equals(x.Value1, y.Value1) || !string.Equals(x.Value2, y.Value2) || x.Value3 != y.Value3 ); return e; } public int GetHashCode(DataModel obj) { return 0; } } The comparer used to find old and new records: internal class MatchingDataComparer : IEqualityComparer<DataModel> { public bool Equals(DataModel x, DataModel y) { return string.Equals(x.Key1, y.Key1) && string.Equals(x.Key2, y.Key2); } public int GetHashCode(DataModel obj) { return 0; } }

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  • Filter to values in collection in one query

    - by dotnetdev
    Hi, I have the following LINQ query: List<string> Types = (List<string>) Directory.GetFiles(@"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727") Where(x => System.IO.Path.GetFileNameWithoutExtension(x).Contains("Microsoft")) .ToList<string>(); How could I modify this so it can only get the values stored in a collection, without writing another LINQ query (which I assume will impact performance?)? Thanks

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  • Collide with rotation of the object

    - by Lahiru
    I'm developing a mirror for lazer beam(Ball sprite). There I'm trying to redirect the laze beam according to the ration degree of the mirror(Rectangle). How can I collide the ball to the correct angle if the colliding object is with some angle(45 deg) rather than colliding back. here is an screen shot of my work here is my code using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace collision { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; Texture2D ballTexture; Rectangle ballBounds; Vector2 ballPosition; Vector2 ballVelocity; float ballSpeed = 30f; Texture2D blockTexture; Rectangle blockBounds; Vector2 blockPosition; private Vector2 origin; KeyboardState keyboardState; //Font SpriteFont Font1; Vector2 FontPos; private String displayText; public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here ballPosition = new Vector2(this.GraphicsDevice.Viewport.Width / 2, this.GraphicsDevice.Viewport.Height * 0.25f); blockPosition = new Vector2(this.GraphicsDevice.Viewport.Width / 2, this.GraphicsDevice.Viewport.Height /2); ballVelocity = new Vector2(0, 1); base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); ballTexture = Content.Load<Texture2D>("ball"); blockTexture = Content.Load<Texture2D>("mirror"); //create rectangles based off the size of the textures ballBounds = new Rectangle((int)(ballPosition.X - ballTexture.Width / 2), (int)(ballPosition.Y - ballTexture.Height / 2), ballTexture.Width, ballTexture.Height); blockBounds = new Rectangle((int)(blockPosition.X - blockTexture.Width / 2), (int)(blockPosition.Y - blockTexture.Height / 2), blockTexture.Width, blockTexture.Height); origin.X = blockTexture.Width / 2; origin.Y = blockTexture.Height / 2; // TODO: use this.Content to load your game content here Font1 = Content.Load<SpriteFont>("SpriteFont1"); FontPos = new Vector2(graphics.GraphicsDevice.Viewport.Width - 100, 20); } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { // TODO: Unload any non ContentManager content here } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> /// private float RotationAngle; float circle = MathHelper.Pi * 2; float angle; protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); // TODO: Add your update logic here //check for collision between the ball and the block, or if the ball is outside the bounds of the screen if (ballBounds.Intersects(blockBounds) || !GraphicsDevice.Viewport.Bounds.Contains(ballBounds)) { //we have a simple collision! //if it has hit, swap the direction of the ball, and update it's position ballVelocity = -ballVelocity; ballPosition += ballVelocity * ballSpeed; } else { //move the ball a bit ballPosition += ballVelocity * ballSpeed; } //update bounding boxes ballBounds.X = (int)ballPosition.X; ballBounds.Y = (int)ballPosition.Y; blockBounds.X = (int)blockPosition.X; blockBounds.Y = (int)blockPosition.Y; keyboardState = Keyboard.GetState(); float val = 1.568017f/90; if (keyboardState.IsKeyDown(Keys.Space)) RotationAngle = RotationAngle + (float)Math.PI; if (keyboardState.IsKeyDown(Keys.Left)) RotationAngle = RotationAngle - val; angle = (float)Math.PI / 4.0f; // 90 degrees RotationAngle = angle; // RotationAngle = RotationAngle % circle; displayText = RotationAngle.ToString(); base.Update(gameTime); } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); // TODO: Add your drawing code here spriteBatch.Begin(); // Find the center of the string Vector2 FontOrigin = Font1.MeasureString(displayText) / 2; spriteBatch.DrawString(Font1, displayText, FontPos, Color.White, 0, FontOrigin, 1.0f, SpriteEffects.None, 0.5f); spriteBatch.Draw(ballTexture, ballPosition, Color.White); spriteBatch.Draw(blockTexture, blockPosition,null, Color.White, RotationAngle,origin, 1.0f, SpriteEffects.None, 0f); spriteBatch.End(); base.Draw(gameTime); } } }

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  • Structuring database for multi-object "activity" and "following" functionalities

    - by romaninsh
    I am working on a web application which operate with different types of objects such as user, profiles, pages etc. All objects have unique object_id. When objects interact it may produce "activity", such as user posting on the page or profile. Activity may be related to multiple objects through their object_id. Users may also follow "objects" and they need to be able to see stream of relevant activity. Could you provide me with some data structure suggestions which would be efficient and scalable? My goal is to show activity limited to the objects which user is following I am not limited by relational databases. Update As I'm getting advices on ORM and how index things, I'd like to again, stress my question. According to my current design model the database structure looks like this: As you can see - it's quite easy to implement database like that. Activity and Follower tables do contain much larger amount of records than the upper level but it's tolerable. But when it comes for me to create a "timeline" table, it becomes a nightmare. For every user I need to reference all the object activities which he follows. In terms of records it easily gets out of control. Please suggest me how to change this structure to avoid timeline creation and also be abel to quickly retrieve activity for any given user. Thanks.

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  • Rotating object along bezier curve: not rotating enough?

    - by Paul
    I tried to follow the instructions from the threads on the forum (Cocos2d rotating sprite while moving with CCBezierBy) with Unity, in order to rotate my object as it moves along a bezier curve. But it does not rotate enough, the angle is too low, it goes up to 6 instead of 90 for example, as you can see on this image (the y eulerAngle is at 6, I would expect it to be around 90 with this curve) : Would you know why it does this? And how to make the rotation toward the next point? Here is the code (in c# with Unity) : (I am comparing x and z to get the angle, and adding the angle to eulerAngles.y so that it rotates around the y axis) void Update () { if ( Input.GetKey("d") ) start = true; if ( start ){ myTime = Time.time; start = false; } float theTime = (Time.time - myTime) *0.5f; if ( theTime < 1 ) { car.position = Spline.Interp( myArray, theTime );//creates the bezier curve counterBezier += Time.deltaTime; //compare 2 positions after 0.1f if ( counterBezier > 0.1f ){ counterBezier = 0; cbDone = false; newpos = car.position; float angle = Mathf.Atan2(newpos.z - oldpos.z, newpos.x - oldpos.x); angle += car.eulerAngles.y; car.eulerAngles = new Vector3(0,angle,0); } else if ( counterBezier > 0 && !cbDone ){ oldpos = car.position; cbDone = true; } Thanks

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  • Box Collider isn't rotating with Game Object

    - by pek
    I have a method that creates a room by instantiating a prefab, places it in a grid and the re-sizes the collider based on a room definition (location in grid, rotation, width and height). Here is the method: public void CreateRoom(RoomAction action) { GameObject roomGameObject = Instantiate(this.roomPrefab, Vector3.zero, action.RoomPrefab.transform.rotation) as GameObject; roomGameObject.transform.parent = this.transform; roomGameObject.transform.localPosition = new Vector3(action.MansionOffsetX, 0, -action.MansionOffsetY) * this.blockSize; roomGameObject.transform.localPosition += new Vector3((action.Room.Width * this.blockSize) / 2, 0, -((action.Room.Height * this.blockSize) / 2)); BoxCollider roomCollider = roomGameObject.GetComponent<BoxCollider>(); roomCollider.isTrigger = true; roomCollider.center = new Vector3(0, this.height / 2, 0); roomCollider.size = new Vector3(action.Room.Width * this.blockSize, this.height, action.Room.Height * this.blockSize); roomGameObject.transform.RotateAroundLocal(roomGameObject.transform.up, Mathf.Deg2Rad * -90 * action.Rotation); } The problem I'm having is that, while the room rotates correctly, but for some reason, the collider isn't rotating with the game object. Here is a screenshot: Any idea on what am I doing wrong?

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  • Scale a game object to Bounds

    - by Spikeh
    I'm trying to scale a lot of dynamically created game objects in Unity3D to the bounds of a sphere collider, based on the size of their current mesh. Each object has a different scale and mesh size. Some are bigger than the AABB of the collider, and some are smaller. Here's the script I've written so far: private void ScaleToCollider(GameObject objectToScale, SphereCollider sphere) { var currentScale = objectToScale.transform.localScale; var currentSize = objectToScale.GetMeshHierarchyBounds().size; var targetSize = (sphere.radius * 2); var newScale = new Vector3 { x = targetSize * currentScale.x / currentSize.x, y = targetSize * currentScale.y / currentSize.y, z = targetSize * currentScale.z / currentSize.z }; Debug.Log("{0} Current scale: {1}, targetSize: {2}, currentSize: {3}, newScale: {4}, currentScale.x: {5}, currentSize.x: {6}", objectToScale.name, currentScale, targetSize, currentSize, newScale, currentScale.x, currentSize.x); //DoorDevice_meshBase Current scale: (0.1, 4.0, 3.0), targetSize: 5, currentSize: (2.9, 4.0, 1.1), newScale: (0.2, 5.0, 13.4), currentScale.x: 0.125, currentSize.x: 2.869114 //RedControlPanelForAirlock_meshBase Current scale: (1.0, 1.0, 1.0), targetSize: 5, currentSize: (0.0, 0.3, 0.2), newScale: (147.1, 16.7, 25.0), currentScale.x: 1, currentSize.x: 0.03400017 objectToScale.transform.localScale = newScale; } And the supporting extension method: public static Bounds GetMeshHierarchyBounds(this GameObject go) { var bounds = new Bounds(); // Not used, but a struct needs to be instantiated if (go.renderer != null) { bounds = go.renderer.bounds; // Make sure the parent is included Debug.Log("Found parent bounds: " + bounds); //bounds.Encapsulate(go.renderer.bounds); } foreach (var c in go.GetComponentsInChildren<MeshRenderer>()) { Debug.Log("Found {0} bounds are {1}", c.name, c.bounds); if (bounds.size == Vector3.zero) { bounds = c.bounds; } else { bounds.Encapsulate(c.bounds); } } return bounds; } After the re-scale, there doesn't seem to be any consistency to the results - some objects with completely uniform scales (x,y,z) seem to resize correctly, but others don't :| Its one of those things I've been trying to fix for so long I've lost all grasp on any of the logic :| Any help would be appreciated!

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  • (LWJGL) Pixel Unpack Buffer Object is Disabled? (glTextImage2D)

    - by OstlerDev
    I am trying to create a render target for my game so that I can re-render at a different screen size. But I am receiving the following error: Exception in thread "main" org.lwjgl.opengl.OpenGLException: Cannot use offsets when Pixel Unpack Buffer Object is disabled Here is the source code for my Render method: // clear screen GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT); // Start FBO Rendering Code // The framebuffer, which regroups 0, 1, or more textures, and 0 or 1 depth buffer. int FramebufferName = GL30.glGenFramebuffers(); GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, FramebufferName); // The texture we're going to render to int renderedTexture = glGenTextures(); // "Bind" the newly created texture : all future texture functions will modify this texture glBindTexture(GL_TEXTURE_2D, renderedTexture); // Give an empty image to OpenGL ( the last "0" ) glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, 1024, 768, 0,GL_RGB, GL_UNSIGNED_BYTE, 0); // Poor filtering. Needed ! glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); // Set "renderedTexture" as our colour attachement #0 GL32.glFramebufferTexture(GL30.GL_FRAMEBUFFER, GL30.GL_COLOR_ATTACHMENT0, renderedTexture, 0); // Set the list of draw buffers. IntBuffer drawBuffer = BufferUtils.createIntBuffer(20 * 20); GL20.glDrawBuffers(drawBuffer); // Always check that our framebuffer is ok if(GL30.glCheckFramebufferStatus(GL30.GL_FRAMEBUFFER) != GL30.GL_FRAMEBUFFER_COMPLETE){ System.out.println("Framebuffer was not created successfully! Exiting!"); return; } // Resets the current viewport GL11.glViewport(0, 0, scaleWidth*scale, scaleHeight*scale); GL11.glMatrixMode(GL11.GL_MODELVIEW); GL11.glLoadIdentity(); // let subsystem paint if (callback != null) { callback.frameRendering(); } // update window contents Display.update(); It is crashing on this line: glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB, 1024, 768, 0,GL_RGB, GL_UNSIGNED_BYTE, 0); I am not really sure why it is crashing and looking around I have not been able to find out why. Any help or insight would be greatly welcome.

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  • SQL SERVER – Get Schema Name from Object ID using OBJECT_SCHEMA_NAME

    - by pinaldave
    Sometime a simple solution have even simpler solutions but we often do not practice it as we do not see value in it or find it useful. Well, today’s blog post is also about something which I have seen not practiced much in codes. We are so much comfortable with alternative usage that we do not feel like switching how we query the data. I was going over forums and I noticed that at one place user has used following code to get Schema Name from ObjectID. USE AdventureWorks2012 GO SELECT s.name AS SchemaName, t.name AS TableName, s.schema_id, t.OBJECT_ID FROM sys.Tables t INNER JOIN sys.schemas s ON s.schema_id = t.schema_id WHERE t.name = OBJECT_NAME(46623209) GO Before I continue let me say I do not see anything wrong with this script. It is just fine and one of the way to get SchemaName from Object ID. However, I have been using function OBJECT_SCHEMA_NAME to get the schema name. If I have to write the same code from the beginning I would have written the same code as following. SELECT OBJECT_SCHEMA_NAME(46623209) AS SchemaName, t.name AS TableName, t.schema_id, t.OBJECT_ID FROM sys.tables t WHERE t.name = OBJECT_NAME(46623209) GO Now, both of the above code give you exact same result. If you remove the WHERE condition it will give you information of all the tables of the database. Now the question is which one is better – honestly – it is not about one is better than other. Use the one which you prefer to use. I prefer to use second one as it requires less typing. Let me ask you the same question to you – which method to get schema name do yo use? and Why? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology

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  • 3D rotation matrices deform object while rotating

    - by Kevin
    I'm writing a small 3D renderer (using an orthographic projection right now). I've run into some trouble with my 3D rotation matrices. They seem to squeeze my 3D object (a box primitive) at certain angles. Here's a live demo (only tested in Google Chrome): http://dl.dropbox.com/u/109400107/3D/index.html The box is viewed from the top along the Y axis and is rotating around the X and Z axis. These are my 3 rotation matrices (Only rX and rZ are being used): var rX = new Matrix([ [1, 0, 0], [0, Math.cos(radiants), -Math.sin(radiants)], [0, Math.sin(radiants), Math.cos(radiants)] ]); var rY = new Matrix([ [Math.cos(radiants), 0, Math.sin(radiants)], [0, 1, 0], [-Math.sin(radiants), 0, Math.cos(radiants)] ]); var rZ = new Matrix([ [Math.cos(radiants), -Math.sin(radiants), 0], [Math.sin(radiants), Math.cos(radiants), 0], [0, 0, 1] ]); Before projecting the verticies I multiply them by rZ and rX like so: vert1.multiply(rZ); vert1.multiply(rX); vert2.multiply(rZ); vert2.multiply(rX); vert3.multiply(rZ); vert3.multiply(rX); The projection itself looks like this: bX = (pos.x + (vert1.x*scale)); bY = (pos.y + (vert1.z*scale)); Where "pos.x" and "pos.y" is an offset for centering the box on the screen. I just can't seem to find a solution to this and I'm still relativly new to working with Matricies. You can view the source-code of the demo page if you want to see the whole thing.

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  • Effective handling of variables in non-object oriented programming

    - by srnka
    What is the best method to use and share variables between functions in non object-oriented program languages? Let's say that I use 10 parameters from DB, ID and 9 other values linked to it. I need to work with all 10 parameters in many functions. I can do it next ways: 1. call functions only with using ID and in every function get the other parameters from DB. Advantage: local variables are clear visible, there is only one input parameter to function Disadvantage: it's slow and there are the same rows for getting parameters in every function, which makes function longer and not so clear 2. call functions with all 10 parameters Advantage: working with local variables, clear function code Disadvantage: many input parameters, what is not nice 3. getting parameters as global variables once and using them everywhere Advantage - clearer code, shorter functions, faster processing Disadvantage - global variables - loosing control of them, possibility of unwanted overwriting (Especially when some functions should change their values) Maybe there is some another way how to implement this and make program cleaner and more effective. Can you say which way is the best for solving this issue?

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  • Java's Object.wait method with nanoseconds: Is this a joke or am I missing something

    - by Krumia
    I was checking out the Java API source code (Java 8) just out of curiosity. And I found this in java/lang/Object.java. There are three methods named wait: public final native void wait(long timeout): This is the core of all wait methods, which has a native implementation. public final void wait(): Just calls wait(0). And then there is public final void wait(long timeout, int nanos). The JavaDoc for the particular method tells me that, This method is similar to the wait method of one argument, but it allows finer control over the amount of time to wait for a notification before giving up. The amount of real time, measured in nanoseconds, is given by: 1000000*timeout+nanos But this is how the methods achieves "finer control over the amount of time to wait": if (nanos >= 500000 || (nanos != 0 && timeout == 0)) { timeout++; } wait(timeout); So this method basically does a crude rounding up of nanoseconds to milliseconds. Not to mention that anything below 500000ns/0.5ms will be ignored. Is this piece of code bad/unnecessary code, or am I missing some unseen virtue of declaring this method, and it's no argument cousin as the way they are?

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  • Sys.WebForms.PageRequestManagerServerErrorException: An entity object cannot be referenced by multiple instances of IEntityChangeTracker [closed]

    - by Mingebag
    `Story: I have a strange error when I try to save something I got this error message An entity object cannot be referenced by multiple instances of IEntityChangeTracker. I really don’t know what that is and why is it appear, it appears only when I try to save something my insert and update is working, only when I try to save something in db from my Telerik grid if (this.annualVacationList != null) { List<AnnualVacation> vacationToSave = this.annualVacationList; IEnumerable<AnnualVacation> existing = paramUser.AnnualVacations; foreach (AnnualVacation toSave in vacationToSave) { AnnualVacation existingItem = existing.Where(x => x.AnnualVacationId == toSave.AnnualVacationId).SingleOrDefault(); if (existingItem == null) { ctx.AddToAnnualVacations(toSave); } else { existingItem.FromDate = toSave.FromDate; existingItem.ToDate = toSave.ToDate; existingItem.WorkingTime = toSave.WorkingTime; existingItem.VacationDays = toSave.VacationDays; } } } ctx.SaveChanges(); } After debugging I have seen that the code brake down in the Project.Name.Designer.cs ..... O.o public void AddToAnnualVacations(AnnualVacation annualVacation) { base.AddObject("AnnualVacations", annualVacation); }

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  • XNA - 2D Rotation of an object to a selected direction

    - by lobsterhat
    I'm trying to figure out the best way of rotating an object towards the directional input of the user. I'm attempting to mimic making turns on ice skates. For instance, if the player is moving right and the input is down and left, the player should start rotating to the right a set amount each tick. I'll calculate a new vector based on current velocity and rotation and apply that to the current velocity. That should give me nice arcing turns, correct? At the moment I've got eight if/else statements for each key combination which in turn check the current rotation: // Rotate to 225 if (keyboardState.IsKeyDown(Keys.Up) && keyboardState.IsKeyDown(Keys.Left)) { // Rotate right if (rotation >= 45 || rotation < 225) { rotation += ROTATION_PER_TICK; } // Rotate left else if (rotation < 45 || rotation > 225) { rotation -= ROTATION_PER_TICK; } } This seems like a sloppy way to do this and eventually, I'll need to do this check about 10 times a tick. Any help toward a more efficient solution is appreciated.

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  • Moving an object using its velocity on a closed curve

    - by Futaro
    I want that an object follows a path, in Peggle game there are some pegs that have movement in a closed path. How can i get the same result? I guess that I can use parametric curve but I need use the velocity and not the position (x, y). I use NAPE and I have this in my gameloop: //circunference angle = angle + 1*(Math.PI / 180); movableBall.position.x = radius * Math.cos(angle)+ h; movableBall.position.y = radius * Math.sin(angle)+ k; it's works but I can not control the velocity, each movableBall must have its own velocity. Besides, from docs of NAPE:"Setting the position of a body is equivalent to simply teleporting the body; for instance moving a kinematic body by position is not the way to go about things.." I want to use: movableBall.velocity.x =?? movableBall.velocity.y = ?? The final idea is to follow others paths like the Lemniscate of Bernoulli. Thanks!

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