Search Results

Search found 17469 results on 699 pages for 'spatial query'.

Page 36/699 | < Previous Page | 32 33 34 35 36 37 38 39 40 41 42 43  | Next Page >

• SQL SERVER – Weekly Series – Memory Lane – #004

  - by pinaldave

  Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Auto Generate Script to Delete Deprecated Fields in Current Database In early career everytime I have to drop a column, I had hard time doing it because I was scared what if that column was needed somewhere in the code. Due to this fear I never dropped any column. I just renamed the column. If the column which I renamed was needed afterwards it was very easy to rename it back again. However, it is not recommended to keep the deleted column renamed in the database. At every interval I used to drop the columns which was prefixed with specific word. This script is 6 years old but still works. Give it a look, I am open for improvements. 2007 Shrinking Truncate Log File – Log Full – Part 2 Shrinking database or mdf file is indeed bad thing and it creates lots of problems. However, once in a while there is legit requirement to shrink the log file – a very rare one. In the rare occasion shrinking or truncating the log file may be the only solution. However, one should make sure to take backup before and after the truncate or shrink as in case of a disaster they can be very useful. Remember that truncating log file will break the log chain and while restore it can create major issue. Anyway, use this feature with caution. 2008 Simple Use of Cursor to Print All Stored Procedures of Database Including Schema This is a very interesting requirement I used to face in my early career days, I needed to print all the Stored procedures of my database. Interesting enough I had written a cursor to do so. Today when I look back at this stored procedure, I believe there will be a much cleaner way to do the same task, however, I still use this SP quite often when I have to document all the stored procedures of my database. Interesting Observation about Order of Resultset without ORDER BY In industry many developers avoid using ORDER BY clause to display the result in particular order thinking that Index is enforcing the order. In this interesting example, I demonstrate that without using ORDER BY, same table and similar query can return different results. Query optimizer always returns results using any method which is optimized for performance. The learning is There is no order unless ORDER BY is used. 2009 Size of Index Table – A Puzzle to Find Index Size for Each Index on Table I asked this puzzle earlier where I asked how to find the Index size for each of the tables. The puzzle was very well received and lots of interesting answers were received. To answer this question I have written following blog posts. I suggest this weekend you try to solve this problem and see if you can come up with a better solution. If not, well here are the solutions. Solution 1 | Solution 2 | Solution 3 Understanding Table Hints with Examples Hints are options and strong suggestions specified for enforcement by the SQL Server query processor on DML statements. The hints override any execution plan the query optimizer might select for a query. The SQL Server Query optimizer is a very smart tool and it makes a better selection of execution plan. Suggesting hints to the Query Optimizer should be attempted when absolutely necessary and by experienced developers who know exactly what they are doing (or in development as a way to experiment and learn). Interesting Observation – TOP 100 PERCENT and ORDER BY I have seen developers and DBAs using TOP very causally when they have to use the ORDER BY clause. Theoretically, there is no need of ORDER BY in the view at all. All the ordering should be done outside the view and view should just have the SELECT statement in it. It was quite common that to save this extra typing by including ordering inside of the view. At several instances developers want a complete resultset and for the same they include TOP 100 PERCENT along with ORDER BY, assuming that this will simulate the SELECT statement with ORDER BY. 2010 SQLPASS Nov 8-11, 2010-Seattle – An Alternative Look at Experience In year 2010 I attended most prestigious SQL Server event SQLPASS between Nov 8-11, 2010 at Seattle. I have only one expression for the event - Best Summit Ever. Instead of writing about my usual routine or the event, I wrote about the interesting things I did and how I felt about it! When I go back and read it, I feel that this is the best event I attended in year 2010. Change Database Access to Single User Mode Using SSMS Image says all. 2011 SQL Server 2012 has introduced new analytic functions. These functions were long awaited and I am glad that they are now here. Before when any of this function was needed, people used to write long T-SQL code to simulate these functions. But now there’s no need of doing so. Having available native function also helps performance as well readability. Function SQLAuthority MSDN CUME_DIST CUME_DIST CUME_DIST FIRST_VALUE FIRST_VALUE FIRST_VALUE LAST_VALUE LAST_VALUE LAST_VALUE LEAD LEAD LEAD LAG LAG LAG PERCENTILE_CONT PERCENTILE_CONT PERCENTILE_CONT PERCENTILE_DISC PERCENTILE_DISC PERCENTILE_DISC PERCENT_RANK PERCENT_RANK PERCENT_RANK Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Prolog - How do you distinguish between just a string, and a variable? [closed]

  - by Mr Prolog

  When you are querying a Prolog database, often you will use terms that start with an uppercase letter as your variables. However, let's say that one of the constraints on your query is that a person's location must be "Dallas", and you want to query all the information in the database who meet those specifications. How would do you correctly make sure that Dallas is not interpreted as a variable to store a value in, and is interpreted as a string instead, for usage as a constraint on the query?

  Read the article

• Better way to search for text in two columns

  - by David

  Here is the scenario. I am making a custom blogging software for my site. I am implementing a search feature. It's not very sophisticated - basically it just takes the search phrase entered and runs this query: $query="SELECT * FROM `blog` WHERE `title` LIKE '%$q%' OR `post` LIKE '%$q%'"; Which is meant to simply search the title and post body for the phrase entered. Is there a better way to do that, keeping in mind how long it would take to run the query on up to 100 rows, each with a post length of up to 1500 characters? I have considered using a LIMIT statement to (sometimes) restrict the number of rows that the query would examine. Good idea?

  Read the article

• Repository query conditions, dependencies and DRY

  - by vFragosop

  To keep it simple, let's suppose an application which has Accounts and Users. Each account may have any number of users. There's also 3 consumers of UserRepository: An admin interface which may list all users Public front-end which may list all users An account authenticated API which should only list it's own users Assuming UserRepository is something like this: class UsersRepository extends DatabaseAbstraction { private function query() { return $this->database()->select('users.*'); } public function getAll() { return $this->query()->exec(); } // IMPORTANT: // Tons of other methods for searching, filtering, // joining of other tables, ordering and such... } Keeping in mind the comment above, and the necessity to abstract user querying conditions, How should I handle querying of users filtering by account_id? I can picture three possible roads: 1. Should I create an AccountUsersRepository? class AccountUsersRepository extends UserRepository { public function __construct(Account $account) { $this->account = $account; } private function query() { return parent::query() ->where('account_id', '=', $this->account->id); } } This has the advantage of reducing the duplication of UsersRepository methods, but doesn't quite fit into anything I've read about DDD so far (I'm rookie by the way) 2. Should I put it as a method on AccountsRepository? class AccountsRepository extends DatabaseAbstraction { public function getAccountUsers(Account $account) { return $this->database() ->select('users.*') ->where('account_id', '=', $account->id) ->exec(); } } This requires the duplication of all UserRepository methods and may need another UserQuery layer, that implements those querying logic on chainable way. 3. Should I query UserRepository from within my account entity? class Account extends Entity { public function getUsers() { return UserRepository::findByAccountId($this->id); } } This feels more like an aggregate root for me, but introduces dependency of UserRepository on Account entity, which may violate a few principles. 4. Or am I missing the point completely? Maybe there's an even better solution? Footnotes: Besides permissions being a Service concern, in my understanding, they shouldn't implement SQL query but leave that to repositories since those may not even be SQL driven.

  Read the article

• Content Query Web Part - How do you OrderBy when you QueryOverride?

  - by Richard JP Le Guen

  How do you order items when you override the QueryOverride property of the Content Query Web Part? I have been given responsibility for a Web Part which extends the Content Query Web Part. The QueryOverride property of this Web Part is programmatically changed. Currently, the Web Part does not function as designed, as it does not order the items according to the appropriate field. If I add an <OrderBy> node to the QueryOverride property I get an error message along the lines of 'something wrong with the query this web part is...' and the Content Query Web Part doesn't seem to have an OrderBy property which I could use instead. The "QueryOverride property" part of this msdn article seems to suggest I should be able to add an <OrderBy> node to the QueryOverride but a number of web sites I've been reading suggest that this is not true. So, wow do you order items when you override the QueryOverride property of the Content Query Web Part?

  Read the article

• How to retrieve only updated/new records since the last query in SQL?

  - by William Choi

  Hi all, I was asked to design a class for caching SQL query results. Calling the class' query method will query and cache the entire set of results at the first time; afterward, each subsequence query will retrieve only the updated portion, and will merge the result into the cache. If the class is required to be generic, i.e. NO knowledge about the db and the tables, do you have any idea? Is it possible, and how to retrieve only updated/new records since the last query? Thanks! William

  Read the article

• How to test a lamda expression var query result is null?

  - by mike

  var query = from emp in dbEmp.Employees join dept in dbEmp.Departments on emp.DeptID equals dept.DeptID where dept.DepartmentName.Contains(this.TextBox1.Text) select new { EmpID = emp.EmpID, EmpName = emp.EmpName, Age = emp.Age, Address = emp.Address, DeptName = dept.DepartmentName }; if (query==null) Label1.Text = "no results match your search"; GridView1.DataSource = query; GridView1.DataBind(); Everything works in the right way, but the label doesn't show the message when query result returns null. The label can show without condition(querry==null). So how to test if a var query result returns nothing? Thanks

  Read the article

• Adding a calculated field to a Query at run time.

  - by JamesB

  I'm getting data using a query in Delphi, and would like to add a calculated field to the query before it runs. The calculated field is using values in code as well as the query so I can't just calculate it in SQL. I know I can attach an OnCalcFields Event to actually make the calculation, but the problem is after adding the calculated field there are no other fields in the query... I did some digging and found that all of the field defs are created but the actual fields are only created if DefaultFields then CreateFields Default Fields is specified procedure TDataSet.DoInternalOpen; begin FDefaultFields := FieldCount = 0; ... end; Which would indicate that if you add fields you only get the fields you added. I would like all the fields in the query AS WELL AS the ones I Add. Is this possible or do I have to add all the fields I'm using as well?

  Read the article

• MySQL GIS and Spatial Extensions - how to map regions and query against them

  - by chibineku

  I am trying to make a smartphone app which will return a list of users within a certain proximity, say 100m. It's easy to get the coordinates of my BlackBerry and write them to a database, but in order to return a list of other users within 100m, I need to pull every other record from the database and compare the distance between the two points, checking to see if it's within range, before outputting that user's information. This is going to be time consuming if there are many users involved. So I would like to map areas (countries, cities, I'm not yet sure of the resolution I'll need) so that I can first target a smaller subset of all users. This will save on processing time. I have read the basics of GIS and spatial querying on the mysql website but to be honest the query is over my head and I hate copying and pasting code without understanding it. Plus it only checks for proximity - I want to first check if a coordinate falls within a certain area. Does anyone have any experience of such matters and feel like giving me some pointers? Resources such as any preexisting databases of points describing countries as polygons would be really helpful too. Many thanks to anyone who takes the time :)

  Read the article

• Dom Traversal to Automate Keyboard Focus - Spatial Navigation

  - by Steve

  I'm going to start with a little background that will hopefully help my question make more sense. I am developing an application for a television. The concept is simple and basically works by overlaying a browser over the video plane of the TV. Now being a TV, there is no mouse or additional pointing device. All interaction is done through a remote control. Therefore, the user needs to be able to visually tell which element they are currently focused upon. To indicate that an element is focused, I currently append a colored transparent image over the element to indicate focus. Now, when a user hits the arrow keys, I need to respond by focusing on the correct elements according to the key pressed. So, if the down arrow is pressed I need to focus on the next focusable element in the DOM tree (which may be a child or sibling), and if they hit the up arrow, I need to respond to the previous element. This would essentially simulate spatial navigation within a browser. I am currently setting an attribute (focusable=true) on any DOM elements that should be able to receive focus. What I would like to do is determine the previous or next focusable element (i.e. attribute focusable=true) and apply focus to the element. I was hoping to traverse the DOM tree to determine the next and previously focusable elements, but I am not sure how to perform this in JQuery, or in general. I was leaning towards trying to use the JQuery tree travesal methods like next(), prev(), etc. What approach would you take to solve this type of issue? Thanks

  Read the article

• Sql Query - Limiting query results

  - by Gublooo

  I am quite certain we cannot use the LIMIT clause for what I want to do - so wanted to find if there are any other ways we can accomplish this. I have a table which captures which user visited which store. Every time a user visits a store, a row is inserted into this table. Some of the fields are shopping_id (primary key) store_id user_id Now what I want is - for a given set of stores, find the top 5 users who have visited the store max number of times. I can do this 1 store at a time as: select store_id,user_id,count(1) as visits from shopping where store_id = 60 group by user_id,store_id order by visits desc Limit 5 This will give me the 5 users who have visited store_id=60 the max times What I want to do is provide a list of 10 store_ids and for each store fetch the 5 users who have visited that store max times select store_id,user_id,count(1) as visits from shopping where store_id in (60,61,62,63,64,65,66) group by user_id,store_id order by visits desc Limit 5 This will not work as the Limit at the end will return only 5 rows rather than 5 rows for each store. Any ideas on how I can achieve this. I can always write a loop and pass 1 store at a time but wanted to know if there is a better way

  Read the article

• MDX: Problem filtering results in MDX query used in Reporting Services query

  - by wgpubs

  Why aren't my results being filtered by the members from my [Group Hierarchy] returned via the filter() statment below? SELECT NON EMPTY {[Measures].[Group Count], [Measures].[Overall Group Count] } ON COLUMNS, NON EMPTY { [Survey].[Surveys By Year].[Survey Year].ALLMEMBERS * [Response Status].[Response Status].[Response Status].ALLMEMBERS} DIMENSION PROPERTIES MEMBER_CAPTION, MEMBER_UNIQUE_NAME ON ROWS FROM ( SELECT ( { [Survey Type].[Survey Type Hierarchy].&[9] } ) ON COLUMNS FROM ( SELECT ( { [Response Status].[Response Status].[All] } ) ON COLUMNS FROM ( SELECT ( STRTOSET(@SurveySurveysByYear, CONSTRAINED) ) ON COLUMNS FROM ( SELECT(filter([Group].[Group Hierarchy].members, instr(@GroupGroupFullName,[Group].[Group Hierarchy].Properties( "Group Full Name" )))) on columns FROM [SysSurveyDW])))) CELL PROPERTIES VALUE, BACK_COLOR, FORE_COLOR, FORMATTED_VALUE, FORMAT_STRING, FONT_NAME, FONT_SIZE, FONT_FLAGS

  Read the article

• Variable in one query is getting into another query in view

  - by Jason Shultz

  I have two foreach statements. The variable from one one is somehow getting into another and i'm not sure how to fix it. Here's my controller: // Categories Page Code function categories($id) { $this->load->model('Business_model'); $data['businessList'] = $this->Business_model->categoryPageList($id); $data['catList'] = $this->Business_model->categoryList(); $data['featured'] = $this->Business_model->frontPageList(); $data['user_id'] = $this->tank_auth->get_user_id(); $data['username'] = $this->tank_auth->get_username(); $data['page_title'] = 'Welcome To Jerome - Largest Ghost Town in America'; $data['page'] = 'category_view'; // pass the actual view to use as a parameter $this->load->view('container',$data); } What happens is categories will only show the businesses in a certain category. The businesses are pulled from the database using the categoryPageList($id) function. Here is that function: function categoryPageList($id) { $this->db->select('b.id, b.busname, b.busowner, b.webaddress, p.thumb, v.title, c.catname, s.specname, p.thumb, c.id'); $this->db->from ('business AS b'); $this->db->where('b.category', $id); $this->db->join('photos AS p', 'p.busid = b.id', 'left'); $this->db->join('video AS v', 'v.busid = b.id', 'left'); $this->db->join('specials AS s', 's.busid = b.id', 'left'); $this->db->join('category As c', 'b.category = c.id', 'left'); $this->db->group_by("b.id"); return $this->db->get(); } And here is the view: <h2>Welcome to Jerome, Arizona</h2> <p>Choose the Category of Business you are interested in:<br/> <?php foreach ($catList->result() as $row): ?> <a href="/site/categories/<?=$row->id?>"><?=$row->catname?></a>, &nbsp; <?php endforeach; ?></p> <table id="businessTable" class="tablesorter"> <thead><tr><th>Business Name</th><th>Business Owner</th><th>Web</th><th>Photos</th><th>Videos</th><th>Specials</th></tr></thead> <?php if(count($businessList) > 0) : foreach ($businessList->result() as $crow): ?> <tr> <td><a href="/site/business/<?=$crow->id?>"><?=$crow->busname?></a></td> <td><?=$crow->busowner?></td> <td><a href="<?=$crow->webaddress?>">Visit Site</a></td> <td> <?php if(isset($crow->thumb)):?> yes <?php else:?> no <?php endif?> </td> <td> <?php if(isset($crow->title)):?> yes <?php else:?> no <?php endif?> </td> <td> <?php if(isset($crow->specname)):?> yes <?php else:?> no <?php endif?> </td> </tr> <?php endforeach; ?> <?php else : ?> <td colspan="4"><p>No Category Selected</p></td> <?php endif; ?> </table> The problem occurs here. <?=$crow->id?> should be showing the row id from the business table. Instead, it's showing the row ID of the category table. so, if i'm viewing /site/categories/6 <?=$crow->id?> will show 6 when it should be showing 10 (the row ID of the only business in that category at this time. How can I fix this?

  Read the article

• How to create a UDF that takes a query string and returns the query's resultset

  - by Martin

  I want to create a stored procedure that takes a simple SELECT statement and return the resultset as a CSV string. So the basic idea is get the sql statement from user input, run it using EXEC(@stmt) and convert the resultset to text using cursors. However, as SQLServer doesn't allow: select * from storedprocedure(@sqlStmt) UDF with EXEC(@sqlStmt) so I tried Insert into #tempTable EXEC(@sqlStmt), but this doesn't work (error = "invalid object name #tempTable"). I'm stuck. Could you please shed some light on this matter? Many thanks EDIT: Actually the output (e.g CSV string) is not important. The problem is I don't know how to assign a cursor to the resultset returned by EXEC. SP and UDF do not work with Exec() while creating a temp table before inserting values is impossible without knowing the input statement. I thought of OPENQUERY but it does not accept variables as its parameters.

  Read the article

• LINQ Query using UDF that receives parameters from the query

  - by Ben Fidge

  I need help using a UDF in a LINQ which calculates a users position from a fixed point. int pointX = 567, int pointY = 534; // random points on a square grid var q = from n in _context.Users join m in _context.GetUserDistance(n.posY, n.posY, pointX, pointY, n.UserId) on n.UserId equals m.UserId select new User() { PosX = n.PosX, PosY = n.PosY, Distance = m.Distance, Name = n.Name, UserId = n.UserId }; The GetUserDistance is just a UDF that returns a single row in a TVP with that users distance from the points deisgnated in pointX and pointY variables, and the designer generates the following for it: [global::System.Data.Linq.Mapping.FunctionAttribute(Name="dbo.GetUserDistance", IsComposable=true)] public IQueryable<GetUserDistanceResult> GetUserDistance([global::System.Data.Linq.Mapping.ParameterAttribute(Name="X1", DbType="Int")] System.Nullable<int> x1, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="X2", DbType="Int")] System.Nullable<int> x2, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="Y1", DbType="Int")] System.Nullable<int> y1, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="Y2", DbType="Int")] System.Nullable<int> y2, [global::System.Data.Linq.Mapping.ParameterAttribute(Name="UserId", DbType="Int")] System.Nullable<int> userId) { return this.CreateMethodCallQuery<GetUserDistanceResult>(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), x1, x2, y1, y2, userId); } when i try to compile i get The name 'n' does not exist in the current context

  Read the article

• How can I get something like Nautilus's "spatial" behaviour in 11.10 and later?

  - by Dylan McCall

  Until recently, Nautilus had an optional "spatial" mode as an alternative to its usual browser mode. Users could enable it by opening Nautilus's preferences and selecting "Open each folder in its own window." Choosing this option resulted in a stripped down interface, and folders would always open in the same place on the screen. It looked something like this: That checkbox is still there, but it doesn't do the same thing: while every folder opens in a new window, those windows are all the same size and positioned the same way. Nautilus doesn't restore the size and position of each folder, which is what spatial mode was all about. This difference really shows if someone opens a folder in a new window, and then opens the same folder again. Nautilus will create another window instead of focusing the existing window. I help someone who is currently using Ubuntu 10.04, and he will be upgrading to 12.04 in the future. He is very comfortable with Nautilus's spatial behaviour and I think he would be disappointed to lose it. Is there an alternative file manager, or perhaps some less obvious option, that will give him an interface similar to the one he is comfortable with?

  Read the article

• Scene graphs and spatial partitioning structures: What do you really need?

  - by tapirath

  I've been fiddling with 2D games for awhile and I'm trying to go into 3D game development. I thought I should get my basics right first. From what I read scene graphs hold your game objects/entities and their relation to each other like 'a tire' would be the child of 'a vehicle'. It's mainly used for frustum/occlusion culling and minimizing the collision checks between the objects. Spatial partitioning structures on the other hand are used to divide a big game object (like the map) to smaller parts so that you can gain performance by only drawing the relevant polygons and again minimizing the collision checks to those polygons only. Also a spatial partitioning data structure can be used as a node in a scene graph. But... I've been reading about both subjects and I've seen a lot of "scene graphs are useless" and "BSP performance gain is irrelevant with modern hardware" kind of articles. Also some of the game engines I've checked like gameplay3d and jmonkeyengine are only using a scene graph (That also may be because they don't want to limit the developers). Whereas games like Quake and Half-Life only use spatial partitioning. I'm aware that the usage of these structures very much depend on the type of the game you're developing so for the sake of clarity let's assume the game is a FPS like Counter-Strike with some better outdoor environment capabilities (like a terrain). The obvious question is which one is needed and why (considering the modern hardware capabilities). Thank you.

  Read the article

• I’m 99% confident that where you are matters

  - by ktegels

  It really has been a long time since I posted anything ofvalue here. Yes, a lot of that is by my own choice and some of you might bewondering if I’ve given up on SQL Server. No, haven’t, it remains a vital toolfor me. But I have become more of user of the product in last couple of yearsrather than somebody who is “internals guru.” To be frank, going from technicaltrainer to University professor has had a lot to do with that. I tend to caremuch less now about squeezing cycles out of execution times...(read more)

  Read the article

• Visually stunning maps and PivotViewer

  - by Rob Farley

  One of the things about PivotViewer is that it runs in the Silverlight platform and can be extended recently. One of my guys at LobsterPot, Roger Noble, has used this to incorporate a Bing Maps layer, showing items which have  Latitude and Longitude values there. We’re already talking to a hospital about using this to allow them to browse their patient data, including showing the patients on a map according to which bed they’re in. Interesting times – this will involve having custom tiles instead of the ones from Bing Maps, but the idea is similar. Of course, we’ll be using Bing Maps to show where the patients live. I should also mention that this is a work-in-progress still. Figuring out how to use PivotViewer isn’t trivial, and we’ve done quite a lot of experimenting to see how to get things working. If you find bugs, please feel free to let me know (rob_farley at hotmail will usually reach me), and we’ll add them to our list. Here are some screenshots that I made recently using the collection at http://pivot.lobsterpot.com.au/flickr – by selecting a tag, you can get a new bunch of images. A couple of images that were taken in Iceland. Some from St Mary’s Lighthouse near Newcastle, UK. And some from around Big Ben in London. I’d recommend using either Firefox or Internet Explorer if you choose to browse this yourself. It seems the Chrome browser support for Silverlight doesn’t quite handle things as nicely as we’d all like. I imagine that at some point, we may enhance the Flickr collection, to be able to search on more than tags, but as a sample collection, it seems to work quite well.

  Read the article

• Data structures for a 2D multi-layered and multi-region map?

  - by DevilWithin

  I am working on a 2D world editor and a world format subsequently. If I were to handle the game "world" being created just as a layered set of structures, either in top or side views, it would be considerably simple to do most things. But, since this editor is meant for 3rd parties, I have no clue how big worlds one will want to make and I need to keep in mind that eventually it will become simply too much to check, handling and comparing stuff that are happening completely away from the player position. I know the solution for this is to subdivide my world into sub regions and stream them on the fly, loading and unloading resources and other data. This way I know a virtually infinite game area is achievable. But, while I know theoretically what to do, I really have a few questions I'd hoped to get answered for some hints about the topic. The logic way to handle the regions is some kind of grid, would you pick evenly distributed blocks with equal sizes or would you let the user subdivide areas by taste with irregular sized rectangles? In case of even grids, would you use some kind of block/chunk neighbouring system to check when the player transposes the limit or just put all those in a simple array? Being a region a different data structure than its owner "game world", when streaming a region, would you deliver the objects to the parent structures and track them for unloading later, or retain the objects in each region for a more "hard-limit" approach? Introducing the subdivision approach to the project, and already having a multi layered scene graph structure on place, how would i make it support the new concept? Would you have the parent node have the layers as children, and replicate in each layer node, a node per region? Or the opposite, parent node owns all the regions possible, and each region has multiple layers as children? Or would you just put the region logic outside the graph completely(compatible with the first suggestion in Q.3) When I say virtually infinite worlds, I mean it of course under the contraints of the variable sizes and so on. Using float positions, a HUGE world can already be made. Do you think its sane to think beyond that? Because I think its ok to stick to this limit since it will never be reached so easily.. As for when to stream a region, I'm implementing it as a collection of watcher cameras, which the streaming system works with to know what to load/unload. The problem here is, i will be needing some kind of warps/teleports built in for my game, and there is a chance i will be teleporting a player to a unloaded region far away. How would you approach something like this? Is it sane to load any region to memory which can be teleported to by a warp within a radius from the player? Sorry for the huge question, any answers are helpful!

  Read the article

• Filtering SQLAlchemy query on attribute_mapped_collection field of relationship

  - by bsa

  I have two classes, Tag and Hardware, defined with a simple parent-child relationship (see the full definition at the end). Now I want to filter a query on Tag using the version field in Hardware through an attribute_mapped_collection, eg: def get_tags(order_code=None, hardware_filters=None): session = Session() query = session.query(Tag) if order_code: query = query.filter(Tag.order_code == order_code) if hardware_filters: for k, v in hardware_filters.iteritems(): query = query.filter(getattr(Tag.hardware, k).version == v) return query.all() But I get: AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator' object associated with Tag.hardware has an attribute 'baseband The same thing happens if I strip it back by hard-coding the attribute, eg: query.filter(Tag.hardware.baseband.version == v) I can do it this way: query = query.filter(Tag.hardware.any(artefact=k, version=v)) But why can't I filter directly through the attribute? Class definitions class Tag(Base): __tablename__ = 'tag' tag_id = Column(Integer, primary_key=True) order_code = Column(String, nullable=False) version = Column(String, nullable=False) status = Column(String, nullable=False) comments = Column(String) hardware = relationship( "Hardware", backref="tag", collection_class=attribute_mapped_collection('artefact'), ) __table_args__ = ( UniqueConstraint('order_code', 'version'), ) class Hardware(Base): __tablename__ = 'hardware' hardware_id = Column(Integer, primary_key=True) tag_id = Column(String, ForeignKey('tag.tag_id')) product_id = Column(String, nullable=True) artefact = Column(String, nullable=False) version = Column(String, nullable=False)

  Read the article

• SQL SERVER – Weekly Series – Memory Lane – #033

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Spatial Database Definition and Research Documents Here is the definition from Wikipedia about spatial database : A spatial database is a database that is optimized to store and query data related to objects in space, including points, lines and polygons. While typical databases can understand various numeric and character types of data, additional functionality needs to be added for databases to process spatial data types. Select Only Date Part From DateTime – Best Practice A very common question which I receive is how to only get Date or Time part from datetime value. In this blog post I explain the same in very simple words. T-SQL Paging Query Technique Comparison (OVER and ROW_NUMBER()) – CTE vs. Derived Table I have received few emails and comments about my post SQL SERVER – T-SQL Paging Query Technique Comparison – SQL 2000 vs SQL 2005. The main question was is this can be done using CTE? Absolutely! What about Performance? It is identical! Please refer above mentioned article for the history of paging. SQL SERVER – Cannot resolve collation conflict for equal to operation One of the very first error I ever encountered in my career was to resolve this conflict. I have blogged about it and I have realized that many others like me who are facing this error. LEN and DATALENGTH of NULL Simple Example Here is the question for you what is the LEN of NULL value? Well it is very easy – just read the blog. Recovery Models and Selection Very simple and easy explanation of the Database Backup Recovery Model and how to select the best option for you. Explanation SQL SERVER Hash Join Hash join gives best performance when two more join tables are joined and at-least one of them have no index or is not sorted. It is also expected that smaller of the either of table can be read in memory completely (though not necessary). Easy Sequence of SELECT FROM JOIN WHERE GROUP BY HAVING ORDER BY SELECT yourcolumns FROM tablenames JOIN tablenames WHERE condition GROUP BY yourcolumns HAVING aggregatecolumn condition ORDER BY yourcolumns NorthWind Database or AdventureWorks Database – Samples Databases In this blog post we learn how to install Northwind database. I also shared the source where one can download this database as that is used in many examples on MSDN help files. sp_HelpText for sp_HelpText – Puzzle A simple quick puzzle – do you know the answer of it? If not, go ahead and read the blog. 2008 SQL SERVER – 2008 – Step By Step Installation Guide With Images When SQL Server 2008 was newly introduced lots of people had no clue how to install SQL Server 2008 and the amount of the question which I used to receive were so much. I wrote this blog post with the spirit that this will help all the newbies to install SQL Server 2008 with the help of images. Still today this blog post has been bible for all of the people who are confused with SQL Server installation. Inline Variable Assignment I loved this feature. I have always wanted this feature to be present in SQL Server. The last time when I met developers from Microsoft SQL Server, I had talked about this feature. I think this feature saves some time but make the code more readable. Introduction to Policy Management – Enforcing Rules on SQL Server If our company policy is to create all the Stored Procedure with prefix ‘usp’ that developers should be just prevented to create Stored Procedure with any other prefix. Let us see a small tutorial how to create conditions and policy which will prevent any future SP to be created with any other prefix. 2009 Performance Counters from System Views – By Kevin Mckenna Many of you are not aware of this fact that access to performance information is readily available in SQL Server and that too without querying performance counters using a custom application or via perfmon. Till now, this fact has remained undisclosed but through this post I would like to explain you can easily access SQL Server performance counter information. Without putting much effort you will come across the system viewsys.dm_os_performance_counters. As the name suggests, this provides you easy access to the SQL Server performance counter information that is passed on to perfmon, but you can get at it via tsql. Customize Toolbar – Remove Debug Button from Toolbar I was fond of SQL Server Debugger feature in SQL Server 2000. To my utter disappointment, this feature was withdrawn from SQL Server 2005. The button of the debugger is similar to a play button and is used to run debugging commands of Visual Studio. Because of this reason, it gets very much infuriating for developers when they are developing on both – Visual Studio and SSMS. Let us now see how we can remove debugging button from SQL Server Management Studio. Effect of Normalization on Index and Performance A very interesting conversation which started from twitter. If you want to read one link this is the link I encourage you to read it. SSMS Feature – Multi-server Queries Using SQL Server Management Studio (SSMS) DBAs can now query multiple servers from one window. It is quite common for DBAs with large amount of servers to maintain and gather information from multiple SQL Servers and create report. This feature is a blessing for the DBAs, as they can now assemble all the information instantaneously without going anywhere. Query Optimizer Hint ROBUST PLAN – Question to You “ROBUST PLAN” is a kind of query hint which works quite differently than other hints. It does not improve join or force any indexes to use; it just makes sure that a query does not crash due to over the limit size of row. Let me elaborate upon it in the blog post. 2010 Do you really know the difference between various date functions available in SQL Server 2012? Here is a three part story where we explored the same with examples: Fastest Way to Restore the Database Difference Between DATETIME and DATETIME2 Difference Between DATETIME and DATETIME2 – WITH GETDATE Shrinking NDF and MDF Files – Readers’ Opinion Shrinking Database always creates performance degradation and increases fragmentation in the database. I suggest that you keep that in mind before you start reading the following comment. If you are going to say Shrinking Database is bad and evil, here I am saying it first and loud. Now, the comment of Imran is written while keeping in mind only the process showing how the Shrinking Database Operation works. Imran has already explained his understanding and requests further explanation. I have removed the Best Practices section from Imran’s comments, as there are a few corrections. 2011 Solution – Puzzle – SELECT * vs SELECT COUNT(*) This is very interesting question and I am very confident that not every one knows the answer to this question. Let me ask you again – Which will be faster SELECT* or SELECT COUNT (*) or do you think this is apples and oranges comparison. 2012 Service Broker and CAP_CPU_PERCENT – Limiting SQL Server Instances to CPU Usage In SQL Server 2012 there are a few enhancements with regards to SQL Server Resource Governor. One of the enhancement is how the resources are allocated. Let me explain you with examples. Let us understand the entire discussion with the help of three different examples. Finding Size of a Columnstore Index Using DMVs One of the very common question I often see is need of the list of columnstore index along with their size and corresponding table name. I quickly re-wrote a script using DMVs sys.indexes and sys.dm_db_partition_stats. This script gives the size of the columnstore index on disk only. I am sure there will be advanced script to retrieve details related to components associated with the columnstore index. However, I believe following script is sufficient to start getting an idea of columnstore index size. Developer Training Resources and Summary Roundup Developer Training - Importance and Significance - Part 1 In this part we discussed the importance of training in the real world. The most important and valuable resource any company is its employee. Employees who have been well-trained will be better at their jobs and produce a better product.  An employee who is well trained obviously knows more about their job and all the technical aspects. I have a very high opinion about training employees and it is the most important task. Developer Training – Employee Morals and Ethics – Part 2 In this part we discussed the most crucial components of training. Often employees are expecting the company to pay for their training and the company expresses no interest in training the employee. Quite often training expenses are the real issue for both the employee and employer. Developer Training – Difficult Questions and Alternative Perspective - Part 3 This part was the most difficult to write as I tried to address a few difficult questions and answers. Training is such a sensitive issue that many developers when not receiving chance for training think about leaving the organization. Developer Training – Various Options for Developer Training – Part 4 In this part I tried to explore a few methods and options for training. The generic feedback I received on this blog post was short and I should have explored each of the subject of the training in details. I believe there are two big buckets of training 1) Instructor Lead Training and 2) Self Lead Training. Developer Training – A Conclusive Summary- Part 5 There is no better motivation than a personal desire to learn new technology. Honestly there is nothing more personal learning. That “change is the only constant” and “adapt & overcome” are the essential lessons of life. One cannot stop the learning and resist the change. In the IT industry “ego of knowing all” and the “resistance to change” are the most challenging issues. A Quick Look at Logging and Ideas around Logging Question: What is the first thing comes to your mind when you hear the word “Logging”? Strange enough I got a different answer every single time. Let me just list what answer I got from my friends. Let us go over them one by one. Beginning Performance Tuning with SQL Server Execution Plan Solution of Puzzle – Swap Value of Column Without Case Statement Earlier this week I asked a question where I asked how to Swap Values of the column without using CASE Statement. Read here: SQL SERVER – A Puzzle – Swap Value of Column Without Case Statement. I have proposed 3 different solutions in the blog posts itself. I had requested the help of the community to come up with alternate solutions and honestly I am stunned and amazed by the qualified entries. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – SOS_SCHEDULER_YIELD – Wait Type – Day 8 of 28

  - by pinaldave

  This is a very interesting wait type and quite often seen as one of the top wait types. Let us discuss this today. From Book On-Line: Occurs when a task voluntarily yields the scheduler for other tasks to execute. During this wait the task is waiting for its quantum to be renewed. SOS_SCHEDULER_YIELD Explanation: SQL Server has multiple threads, and the basic working methodology for SQL Server is that SQL Server does not let any “runnable” thread to starve. Now let us assume SQL Server OS is very busy running threads on all the scheduler. There are always new threads coming up which are ready to run (in other words, runnable). Thread management of the SQL Server is decided by SQL Server and not the operating system. SQL Server runs on non-preemptive mode most of the time, meaning the threads are co-operative and can let other threads to run from time to time by yielding itself. When any thread yields itself for another thread, it creates this wait. If there are more threads, it clearly indicates that the CPU is under pressure. You can fun the following DMV to see how many runnable task counts there are in your system. SELECT scheduler_id, current_tasks_count, runnable_tasks_count, work_queue_count, pending_disk_io_count FROM sys.dm_os_schedulers WHERE scheduler_id < 255 GO If you notice a two-digit number in runnable_tasks_count continuously for long time (not once in a while), you will know that there is CPU pressure. The two-digit number is usually considered as a bad thing; you can read the description of the above DMV over here. Additionally, there are several other counters (%Processor Time and other processor related counters), through which you can refer to so you can validate CPU pressure along with the method explained above. Reducing SOS_SCHEDULER_YIELD wait: This is the trickiest part of this procedure. As discussed, this particular wait type relates to CPU pressure. Increasing more CPU is the solution in simple terms; however, it is not easy to implement this solution. There are other things that you can consider when this wait type is very high. Here is the query where you can find the most expensive query related to CPU from the cache Note: The query that used lots of resources but is not cached will not be caught here. SELECT SUBSTRING(qt.TEXT, (qs.statement_start_offset/2)+1, ((CASE qs.statement_end_offset WHEN -1 THEN DATALENGTH(qt.TEXT) ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)+1), qs.execution_count, qs.total_logical_reads, qs.last_logical_reads, qs.total_logical_writes, qs.last_logical_writes, qs.total_worker_time, qs.last_worker_time, qs.total_elapsed_time/1000000 total_elapsed_time_in_S, qs.last_elapsed_time/1000000 last_elapsed_time_in_S, qs.last_execution_time, qp.query_plan FROM sys.dm_exec_query_stats qs CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp ORDER BY qs.total_worker_time DESC -- CPU time You can find the most expensive queries that are utilizing lots of CPU (from the cache) and you can tune them accordingly. Moreover, you can find the longest running query and attempt to tune them if there is any processor offending code. Additionally, pay attention to total_worker_time because if that is also consistently higher, then  the CPU under too much pressure. You can also check perfmon counters of compilations as they tend to use good amount of CPU. Index rebuild is also a CPU intensive process but we should consider that main cause for this query because that is indeed needed on high transactions OLTP system utilized to reduce fragmentations. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All of the discussions of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

  Read the article

• SQL SERVER – Error: Fix – Msg 208 – Invalid object name ‘dbo.backupset’ – Invalid object name ‘dbo.backupfile’

  - by pinaldave

  Just a day before I got a very interesting email. Here is the email (modified a bit to make it relevant to this blog post). “Pinal, We are facing a very strange issue. One of our query  related to backup files and backup set has stopped working suddenly in SSMS. It works fine in application where we have and in the stored procedure but when we have it in our SSMS it gives following error. Msg 208, Level 16, State 1, Line 1 Invalid object name ‘dbo.backupfile’. Here are our queries which we are trying to execute. SELECT name, database_name, backup_size, TYPE, compatibility_level, backup_set_id FROM dbo.backupset; SELECT logical_name, backup_size, file_type FROM dbo.backupfile; This query gives us details related to backupset and backup files when the backup was taken.” When I receive this kind of email, usually I have no answers directly. The claim that it works in stored procedure and in application but not in SSMS gives me no real data. I have requested him to very first check following two things: If he is connected to correct server? His answer was yes. If he has enough permissions? His answer was he was logged in as an admin. This means there was something more to it and I requested him to send me a screenshot of the his SSMS. He promptly sends that to me and as soon as I receive the screen shot I knew what was going on. Before I say anything take a look at the screenshot yourself and see if you can figure out why his queries are not working in SSMS. Just to make your life a bit easy, I have already given a hint in the image. The answer is very simple, the context of the database is master database. To execute above two queries the context of the database has to be msdb. Tables backupset and backupfile belong to the database msdb only. Here are two workaround or solution to above problem: 1) Change context to MSDB Above two queries when they will run as following they will not error out and will give the accurate desired result. USE msdb GO SELECT name, database_name, backup_size, TYPE, compatibility_level, backup_set_id FROM dbo.backupset; SELECT logical_name, backup_size, file_type FROM dbo.backupfile; 2) Prefix the query with msdb There are cases above script used in stored procedure or part of big query, it is not possible to change the context of the whole query to any specific database. Use three part naming convention and prefix them with msdb. SELECT name, database_name, backup_size, TYPE, compatibility_level, backup_set_id FROM msdb.dbo.backupset; SELECT logical_name, backup_size, file_type FROM msdb.dbo.backupfile; Very simple solution but sometime keeps people wondering for an answer. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL SERVER – Data Pages in Buffer Pool – Data Stored in Memory Cache

  - by pinaldave

  This will drop all the clean buffers so we will be able to start again from there. Now, run the following script and check the execution plan of the query. Have you ever wondered what types of data are there in your cache? During SQL Server Trainings, I am usually asked if there is any way one can know how much data in a table is stored in the memory cache? The more detailed question I usually get is if there are multiple indexes on table (and used in a query), were the data of the single table stored multiple times in the memory cache or only for a single time? Here is a query you can run to figure out what kind of data is stored in the cache. USE AdventureWorks GO SELECT COUNT(*) AS cached_pages_count, name AS BaseTableName, IndexName, IndexTypeDesc FROM sys.dm_os_buffer_descriptors AS bd INNER JOIN ( SELECT s_obj.name, s_obj.index_id, s_obj.allocation_unit_id, s_obj.OBJECT_ID, i.name IndexName, i.type_desc IndexTypeDesc FROM ( SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id ,allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.hobt_id AND (au.type = 1 OR au.type = 3) UNION ALL SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id, allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.partition_id AND au.type = 2 ) AS s_obj LEFT JOIN sys.indexes i ON i.index_id = s_obj.index_id AND i.OBJECT_ID = s_obj.OBJECT_ID ) AS obj ON bd.allocation_unit_id = obj.allocation_unit_id WHERE database_id = DB_ID() GROUP BY name, index_id, IndexName, IndexTypeDesc ORDER BY cached_pages_count DESC; GO Now let us run the query above and observe the output of the same. We can see in the above query that there are four columns. Cached_Pages_Count lists the pages cached in the memory. BaseTableName lists the original base table from which data pages are cached. IndexName lists the name of the index from which pages are cached. IndexTypeDesc lists the type of index. Now, let us do one more experience here. Please note that you should not run this test on a production server as it can extremely reduce the performance of the database. DBCC DROPCLEANBUFFERS This will drop all the clean buffers and we will be able to start again from there. Now run following script and check the execution plan for the same. USE AdventureWorks GO SELECT UnitPrice, ModifiedDate FROM Sales.SalesOrderDetail WHERE SalesOrderDetailID BETWEEN 1 AND 100 GO The execution plans contain the usage of two different indexes. Now, let us run the script that checks the pages cached in SQL Server. It will give us the following output. It is clear from the Resultset that when more than one index is used, datapages related to both or all of the indexes are stored in Memory Cache separately. Let me know what you think of this article. I had a great pleasure while writing this article because I was able to write on this subject, which I like the most. In the next article, we will exactly see what data are cached and those that are not cached, using a few undocumented commands. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL DMV

  Read the article

< Previous Page | 32 33 34 35 36 37 38 39 40 41 42 43  | Next Page >