Search Results

Search found 67143 results on 2686 pages for 'complex data types'.

Page 57/2686 | < Previous Page | 53 54 55 56 57 58 59 60 61 62 63 64  | Next Page >

  • Possible ways of representing data in memory (.net)

    - by This is it
    Hi What are the possible ways of representing data in memory in .Net (or in general)? It would be great if data could be sorted and looked up by key (or multiple keys). We are thinking to use collections, arrays, list of collections/arrays. One object would be in several collections (one sorted asc, other desc, etc.). Maybe this is not a good idea, and we would like to hear some other possible solutions. Thank you

    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 – ASYNC_IO_COMPLETION – Wait Type – Day 11 of 28

    - by pinaldave
    For any good system three things are vital: CPU, Memory and IO (disk). Among these three, IO is the most crucial factor of SQL Server. Looking at real-world cases, I do not see IT people upgrading CPU and Memory frequently. However, the disk is often upgraded for either improving the space, speed or throughput. Today we will look at another IO-related wait type. From Book On-Line: Occurs when a task is waiting for I/Os to finish. ASYNC_IO_COMPLETION Explanation: Any tasks are waiting for I/O to finish. If by any means your application that’s connected to SQL Server is processing the data very slowly, this type of wait can occur. Several long-running database operations like BACKUP, CREATE DATABASE, ALTER DATABASE or other operations can also create this wait type. Reducing ASYNC_IO_COMPLETION wait: When it is an issue related to IO, one should check for the following things associated to IO subsystem: Look at the programming and see if there is any application code which processes the data slowly (like inefficient loop, etc.). Note that it should be re-written to avoid this  wait type. Proper placing of the files is very important. We should check the file system for proper placement of the files – LDF and MDF on separate drive, TempDB on another separate drive, hot spot tables on separate filegroup (and on separate disk), etc. Check the File Statistics and see if there is a higher IO Read and IO Write Stall SQL SERVER – Get File Statistics Using fn_virtualfilestats. Check event log and error log for any errors or warnings related to IO. If you are using SAN (Storage Area Network), check the throughput of the SAN system as well as configuration of the HBA Queue Depth. In one of my recent projects, the SAN was performing really badly and so the SAN administrator did not accept it. After some investigations, he agreed to change the HBA Queue Depth on the development setup (test environment). As soon as we changed the HBA Queue Depth to quite a higher value, there was a sudden big improvement in the performance. It is very likely to happen that there are no proper indexes on the system and yet there are lots of table scans and heap scans. Creating proper index can reduce the IO bandwidth considerably. If SQL Server can use appropriate cover index instead of clustered index, it can effectively reduce lots of CPU, Memory and IO (considering cover index has lesser columns than cluster table and all other; it depends upon the situation). You can refer to the following two articles I wrote that talk about how to optimize indexes: Create Missing Indexes Drop Unused Indexes Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) Read all the post in the Wait Types and Queue series. 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 the discussions of Wait Stats in this blog are generic and vary 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 – IO_COMPLETION – Wait Type – Day 10 of 28

    - by pinaldave
    For any good system three things are vital: CPU, Memory and IO (disk). Among these three, IO is the most crucial factor of SQL Server. Looking at real-world cases, I do not see IT people upgrading CPU and Memory frequently. However, the disk is often upgraded for either improving the space, speed or throughput. Today we will look at an IO-related wait types. From Book On-Line: Occurs while waiting for I/O operations to complete. This wait type generally represents non-data page I/Os. Data page I/O completion waits appear as PAGEIOLATCH_* waits. IO_COMPLETION Explanation: Any tasks are waiting for I/O to finish. This is a good indication that IO needs to be looked over here. Reducing IO_COMPLETION wait: When it is an issue concerning the IO, one should look at the following things related to IO subsystem: Proper placing of the files is very important. We should check the file system for proper placement of files – LDF and MDF on a separate drive, TempDB on another separate drive, hot spot tables on separate filegroup (and on separate disk),etc. Check the File Statistics and see if there is higher IO Read and IO Write Stall SQL SERVER – Get File Statistics Using fn_virtualfilestats. Check event log and error log for any errors or warnings related to IO. If you are using SAN (Storage Area Network), check the throughput of the SAN system as well as the configuration of the HBA Queue Depth. In one of my recent projects, the SAN was performing really badly so the SAN administrator did not accept it. After some investigations, he agreed to change the HBA Queue Depth on development (test environment) set up and as soon as we changed the HBA Queue Depth to quite a higher value, there was a sudden big improvement in the performance. It is very possible that there are no proper indexes in the system and there are lots of table scans and heap scans. Creating proper index can reduce the IO bandwidth considerably. If SQL Server can use appropriate cover index instead of clustered index, it can effectively reduce lots of CPU, Memory and IO (considering cover index has lesser columns than cluster table and all other; it depends upon the situation). You can refer to the two articles that I wrote; they are about how to optimize indexes: Create Missing Indexes Drop Unused Indexes Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) 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 the discussions of Wait Stats in this blog are generic and vary 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 Types, SQL White Papers, T SQL, Technology

    Read the article

  • SQL SERVER – Speed Up! – Parallel Processes and Unparalleled Performance – TechEd 2012 India

    - by pinaldave
    TechEd India 2012 is just around the corner and I will be presenting there on two different session. SQL Server Performance Tuning is a very challenging subject that requires expertise in Database Administration and Database Development. I always have enjoyed talking about SQL Server Performance tuning subject. Just like doctors I like to call my every attempt to improve the performance of SQL Server queries and database server as a practice too. I have been working with SQL Server for more than 8 years and I believe that many of the performance tuning concept I have mastered. However, performance tuning is not a simple subject. However there are occasions when I feel stumped, there are occasional when I am not sure what should be the next step. When I face situation where I cannot figure things out easily, it makes me most happy because I clearly see this as a learning opportunity. I have been presenting in TechEd India for last three years. This is my fourth time opportunity to present a technical session on SQL Server. Just like every other year, I decided to present something different, something which I have spend years of learning. This time, I am going to present about parallel processes. It is widely believed that more the CPU will improve performance of the server. It is true in many cases. However, there are cases when limiting the CPU usages have improved overall health of the server. I will be presenting on the subject of Parallel Processes and its effects. I have spent more than a year working on this subject only. After working on various queries on multi-CPU systems I have personally learned few things. In coming TechEd session, I am going to share my experience with parallel processes and performance tuning. Session Details Title: Speed Up! – Parallel Processes and Unparalleled Performance (Add to Calendar) Abstract: “More CPU More Performance” – A  very common understanding is that usage of multiple CPUs can improve the performance of the query. To get maximum performance out of any query – one has to master various aspects of the parallel processes. In this deep dive session, we will explore this complex subject with a very simple interactive demo. An attendee will walk away with proper understanding of CX_PACKET wait types, MAXDOP, parallelism threshold and various other concepts. Date and Time: March 23, 2012, 12:15 to 13:15 Location: Hotel Lalit Ashok - Kumara Krupa High Grounds, Bengaluru – 560001, Karnataka, India. Add to Calendar Please submit your questions in the comments area and I will be for sure discussing them during my session. If I pick your question to discuss during my session, here is your gift I commit right now – SQL Server Interview Questions and Answers Book. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology Tagged: TechEd, TechEdIn

    Read the article

  • Transferring data from Salesforce using Apex Data Loader to Oracle

    - by Barret
    While attempting to transfer data from Salesforce using Apex Data Loader to Oracle Keep getting the following error: 26937 [databaseAccountExtract] FATAL com.salesforce.dataloader.dao.database.Data baseContext - Error getting value for SQL parameter: nkey__c. Please make sure that the value exists in the configuration file or is passed in. Database conf iguration: insertAccount. The database-conf.xml has the following beans: <bean id="insertAccount" class="com.salesforce.dataloader.dao.database.DatabaseConfig" singleton="true"> <property name="sqlConfig" ref="insertAccountSql"/> <property name="dataSource" ref="dbDataSource"/> </bean> <bean id="insertAccountSql" class="com.salesforce.dataloader.dao.database.SqlConfig" singleton="true"> <property name="sqlString"> <value> INSERT INTO VANTROPO.SF_ACCOUNTCHANNEL (nkey__c) VALUES (@nkey__c@) </value> </property> <property name="sqlParams"> <map> <entry key="nkey__c" value="java.lang.String"/> </map> </property> </bean> The SDL (mapping file) has the following values: # Account Insert Mapping values for query from Salesforce (left) and insert/update to Oracle (right) # SalesforceFieldName=OracleFieldName nkey__c=NKEY__C Any help appreciated.

    Read the article

  • Error using Dynamic Data Filtering: missing datasource

    - by sebastiaan
    I am trying to use the ASP.NET Dynamic Data Filtering project, but I'm running into a problem during the configuration. I'm following the instructions on the author's blog, and everything works like described. Then it tells me to change the datasource using the designer view. I am told to select the "GridDataSource" in the "Configure data source" wizard. This option is not there though. I get all of the classes in my project, including the DataContext that was generated by Linq. When I choose "Show only DataContext objects", the dropdown ("Choose your context object:") is completely empty. When I turn of the checkbox and choose my DataContext class, I get asked which table I want and all that. But, as the whole purpose of a Dynamic Data site is NOT to use one single table, that's not much help. So I've looked at the instructions again and copied the resulting datasource from the example: <asp:DynamicLinqDataSource ID="GridDataSource" runat="server" EnableDelete="True" EnableUpdate="True"></asp:DynamicLinqDataSource> Which is exactly what I had, without the "WhereParameters" nodes in there. Now, when I run the list page however, I get an exception about a missing datasource from the filtering component. Of course when I remove the DynamicFilterRepeater, it works again. This is the meat of the exception: [InvalidOperationException: Missing DataSource] Catalyst.Web.DynamicData.DynamicFilterRepeater.GetTable() in D:\Catalyst\Projects\DynamicData\Project\Trunk\DynamicData\DynamicData\DynamicFilterRepeater.cs:74 Catalyst.Web.DynamicData.DynamicFilterRepeater.GetFilters() in D:\Catalyst\Projects\DynamicData\Project\Trunk\DynamicData\DynamicData\DynamicFilterRepeater.cs:81 Catalyst.Web.DynamicData.DynamicFilterRepeater.OnInit(EventArgs e) in D:\Catalyst\Projects\DynamicData\Project\Trunk\DynamicData\DynamicData\DynamicFilterRepeater.cs:106 How do I make the DynamicFilterRepeater recognize my datasource? I'm using VS2010 Pro, on a Win7 machine.

    Read the article

  • Memory efficient way of inserting an array of objects with Core Data

    - by randombits
    I'm working on a piece of code for an iPhone application that fetches a bunch of data from a server and builds objects from it on the client. It ends up creating roughly 40,000 objects. They aren't displayed to the user, I just need to create instances of NSManagedObject and store them to persistent storage. Am I wrong in thinking that the only way to do this is to create a single object, then save the context? is it best to create the objects all at once, then somehow save them to the context after they're created and stored in some set or array? If so, can one show some example code for how this is done or point me in the direction to code where this is done? The objects themselves are relatively straight forward models with string or integer attributes and don't contain any complex relationships.

    Read the article

  • RESTful WCF Data Service Authentication

    - by Adrian Grigore
    Hi, I'd like to implement a REST api to an existing ASP.NET MVC website. I've managed to set up WCF Data services so that I can browse my data, but now the question is how to handle authentication. Right now the data service is secured via the site's built in forms authentication, and that's ok when accessing the service from AJAX forms. However, It's not ideal for a RESTful api. What I would like as an alternative to forms authentication is for the users to simply embed the user name and password into the url to the web service or as request parameters. For example, if my web service is usually accessible as http://localhost:1234/api.svc I'd like to be able to access it using the url http://localhost:1234/api.svc/{login}/{password} So, my questions are as follows: Is this a sane approach? If yes, how can I implement this? It seems trivial redirecting GET requests so that the login and password are attached as GET parameters. I also know how to inspect the http context and use those parameters to filter the results. But I am not sure if / how the same approach could be applied to POST, PUT and DELETE requests. Thanks, Adrian

    Read the article

  • asp.net Dynamic Data Site with own MetaData

    - by loviji
    Hello, I'm searching info about configuring own MetaData in asp.NET Dynamic Site. For example. I have a table in MS Sql Server with structure shown below: CREATE TABLE [dbo].[someTable]( [id] [int] NOT NULL, [pname] [nvarchar](20) NULL, [FullName] [nvarchar](50) NULL, [age] [int] NULL) and I there are 2 Ms Sql tables (I've created), sysTables and sysColumns. sysTables: ID sysTableName TableName TableDescription 1 | someTable |Persons |All Data about Persons in system sysColumns: ID TableName sysColumnName ColumnName ColumnDesc ColumnType MUnit 1 |someTable | sometable_pname| Name | Persona Name(ex. John)| nvarchar(20) | null 2 |someTable | sometable_Fullname| Full Name | Persona Name(ex. John Black)| nvarchar(50) | null 3 |someTable | sometable_age| age | Person age| int | null I want that, in Details/Edit/Insert/List/ListDetails pages use as MetaData sysColumns and sysTableData. Because, for ex. in DetailsPage fullName, it is not beatiful as Full Name . someIdea, is it possible? thanks Updated:: In List Page to display data from sysTables (metaData table) I've modified <h2 class="DDSubHeader"><%= tableName%></h2>. public string tableName; protected void Page_Init(object sender, EventArgs e) { table = DynamicDataRouteHandler.GetRequestMetaTable(Context); //added by me uqsikDataContext sd=new uqsikDataContext(); tableName = sd.sysTables.Where(n => n.sysTableName == table.DisplayName).FirstOrDefault().TableName; //end GridView1.SetMetaTable(table, table.GetColumnValuesFromRoute(Context)); GridDataSource.EntityTypeName = table.EntityType.AssemblyQualifiedName; if (table.EntityType != table.RootEntityType) { GridQueryExtender.Expressions.Add(new OfTypeExpression(table.EntityType)); } } so, what about sysColums? How can I get Data from my sysColumns table?

    Read the article

  • Jasper report exports empty data in PDF format when there is more data

    - by stanley
    I have a report to be exported in excel, pdf and word using jasper reports. I use xml file as the DataSource for the report, but when the data increases jasper report exports empty file in only for PDF format, when i reduce the data content it export the data available correctly. is there any limitation to pdf size? , how can we manage the size in jasper reports from java? My jrxml is really big, so i cannot add it here, i have added my java code which i use to export the content:- JRAbstractExporter exporter = null; if (format.equals("pdf")) { exporter = new JRPdfExporter(); jasperPrint.setPageWidth(Integer.parseInt( pWidth )); } else if (format.equals("xls")) { exporter = new JRXlsExporter(); } else if (format.equals("doc")) { jasperPrint.setPageWidth(Integer.parseInt( pWidth )); } exporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint); exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, outputStream_); exporter.exportReport(); contents = outputStream_.toByteArray(); response.setContentType("application/"+format); response.addHeader("Content-disposition", "attachment;filename=" + name.toString() + "."+format);

    Read the article

  • Data loss when downloading data from LDAP server

    - by Ricky D'Amelio
    Hi there. This question comes from a previous one I asked about handling NSData objects: http://stackoverflow.com/questions/2453785/converting-nsdata-to-an-nsstring-representation-is-failing. I have reached the point where I am taking an NSImage, turning it into NSData and uploading those data bytes to the LDAP server. I am doing this like so; //connected successfully to LDAP server above... struct berval photo_berval; struct berval *jpegPhoto_values[2]; photo_berval.bv_len = [photo length]; photo_berval.bv_val = [photo bytes]; jpegPhoto_values[0] = &photo_berval; jpegPhoto_values[1] = NULL; mod.mod_type = "jpegPhoto"; mod.mod_op = LDAP_MOD_REPLACE|LDAP_MOD_BVALUES; mod.mod_bvalues = jpegPhoto_values; mods[0] = &mod; mods[1] = NULL; //perform the modify operation rc = ldap_modify_ext_s(ld, givenModifyEntry, mods, NULL, NULL); That happens with no errors, and you can see a big blob of data when you're in the command line. My problem is, when I go to access the same data at a later stage, I am getting an image file back that's about 120 times smaller than the original image. //find the jpegPhoto attribute photoA = ldap_first_attribute(ld, photoE, &photoBer); while (strcasecmp(photoA, "jpegphoto") != 0) { photoA = ldap_next_attribute(ld, photoE, photoBer); } //get the value of the attribute if ((list_of_photos = ldap_get_values_len(ld, photoE, photoA)) != NULL) { //get the first JPEG photo_data = *list_of_photos[0]; selectedPictureData = [NSData dataWithBytes:&photo_data length:sizeof(photo_data)]; [selectedPictureData writeToFile:@"/Users/username/Desktop/Photo 2.jpg" atomically:YES]; NSLog (@"%@", selectedPictureData); Has anyone successfully done this before or can anyone see what I might be doing wrong? I appreciate anyone's help. Sorry to post so many questions! Ricky.

    Read the article

  • Pros and cons of making database IDs consistent and "readable"

    - by gmale
    Question Is it a good rule of thumb for database IDs to be "meaningless?" Conversely, are there significant benefits from having IDs structured in a way where they can be recognized at a glance? What are the pros and cons? Background I just had a debate with my coworkers about the consistency of the IDs in our database. We have a data-driven application that leverages spring so that we rarely ever have to change code. That means, if there's a problem, a data change is usually the solution. My argument was that by making IDs consistent and readable, we save ourselves significant time and headaches, long term. Once the IDs are set, they don't have to change often and if done right, future changes won't be difficult. My coworkers position was that IDs should never matter. Encoding information into the ID violates DB design policies and keeping them orderly requires extra work that, "we don't have time for." I can't find anything online to support either position. So I'm turning to all the gurus here at SA! Example Imagine this simplified list of database records representing food in a grocery store, the first set represents data that has meaning encoded in the IDs, while the second does not: ID's with meaning: Type 1 Fruit 2 Veggie Product 101 Apple 102 Banana 103 Orange 201 Lettuce 202 Onion 203 Carrot Location 41 Aisle four top shelf 42 Aisle four bottom shelf 51 Aisle five top shelf 52 Aisle five bottom shelf ProductLocation 10141 Apple on aisle four top shelf 10241 Banana on aisle four top shelf //just by reading the ids, it's easy to recongnize that these are both Fruit on Aisle 4 ID's without meaning: Type 1 Fruit 2 Veggie Product 1 Apple 2 Banana 3 Orange 4 Lettuce 5 Onion 6 Carrot Location 1 Aisle four top shelf 2 Aisle four bottom shelf 3 Aisle five top shelf 4 Aisle five bottom shelf ProductLocation 1 Apple on aisle four top shelf 2 Banana on aisle four top shelf //given the IDs, it's harder to see that these are both fruit on aisle 4 Summary What are the pros and cons of keeping IDs readable and consistent? Which approach do you generally prefer and why? Is there an accepted industry best-practice?

    Read the article

  • Project setup for an ADO.NET/WCF DataService

    - by Slauma
    I'd like to implement a ADO.NET/WCF DataService and I am wondering what's the best way to setup a project in VS2008 SP1 for this purpose. Currently I have an ASP.NET web application project (not of "WebSite" project type). The data access layer is an Entity model (EF version 1) with SQL Server database. I have the Entity Model in a separate DLL project and the web application project references to this assembly for all data accesses. The ADO.NET/WCF DataService needs to communicate with the Entity model/database as well. It has to be hosted on the same web server (IIS 7.5) together with the web application. Since the DataService is not directly related to that specific web application (though it will provide and modify data from/in the same database the web application uses as well) my basic idea was to separate the DataService in its own new project (which also references the Entity Model DLL). Now I have seen that there is no project type "ADO.NET/WCF DataService" in VS2008 SP1. It seems only possible to add a DataService as an element to other existing projects, for instance Web Application projects. Why isn't there a separate DataService project type? Does this mean now that I have to add the DataService as an element to my Web Application project? Or shall I create a new Web Application project and add a DataService to it? (I could delete the pregenerated default.aspx since I do not need any web pages in this project.) What's the best way? Thank you for suggestions in advance!

    Read the article

  • Core Data 1-to-many relationship: List all related objects as section header in UITableView

    - by Snej
    Hi: I struggle with Core Data on the iPhone about the following: I have a 1-to-many relationship in Core Data. Assume the entities are called recipe and category. A category can have many recipes. I accomplished to get all recipes listed in a UITableView with section headers named after the category. What i want to achieve is to list all categories as section header, even those which have no recipe: category1 <--- this one should be displayed too category2 recipe_x recipe_y category3 recipe_z NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Recipe" inManagedObjectContext:managedObjectContext]; [fetchRequest setEntity:entity]; [fetchRequest setFetchBatchSize:10]; NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc] initWithKey:@"category.categoryName" ascending:YES]; NSSortDescriptor *sortDescriptor2 = [[NSSortDescriptor alloc] initWithKey:@"recipeName" ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor1,sortDescriptor2, nil]; [fetchRequest setSortDescriptors:sortDescriptors]; NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"category.categoryName" cacheName:@"Recipes"]; What is the most elegant way to achieve this with core data?

    Read the article

  • Empty data problem - data layer or DAL?

    - by luckyluke
    I designing the new App now and giving the following question a lot of thought. I consume a lot of data from the warehouse, and the entities have a lot of dictionary based values (currency, country, tax-whatever data) - dimensions. I cannot be assured though that there won't be nulls. So I am thinking: create an empty value in each of teh dictionaries with special keyID - ie. -1 do the ETL (ssis) do the correct stuff and insert -1 where it needs to let the DAL know that -1 is special (Static const whatever thing) don't care in the code to check for nullness of dictionary entries because THEY will always have a value But maybe I should be thinking: import data AS IS let the DAL do the thinking using empty record Pattern still don't care in the code because business layer will have what it needs from DAL. I think is more of a approach thing but maybe i am missing something important here... What do You think? Am i clear? Please don't confuse it with empty record problem. I do use emptyCustomer think all the time and other defaults too.

    Read the article

  • Core Data - Entity Relationships Not Working as expected

    - by slimms
    I have set up my data model in xcode like so EntityA AttA1 AttA2 EntityB AttB1 AttB2 AttB3 I then set up the relationships EntityA Name: rlpToEntityB Destination: EntityB Inverse: rlpToEntityA To Many: Checked EntityB Name: rlpToEntityA Destination: EntityA Inverse: rlpToEntityB To Many: UnChecked i.e. relationship between the two where Each one of EntityA can have many EntityB's It is my understanding that if i fetch a subset of EntityB's I can then retrieve the values for the related EntityA's. I have this working so that i can retrieve the EntityB values using NSManagedObject *objMO = [fetchedResultsController objectAtIndexPath:indexPath]; strValueFromEntityB = [objMO valueForKey:@"AttB1"]; However, if I try to retrieve a related value from EntityA by doing the following strValueFromEntityA = [objMO valueForKey:@"AttA1"]; I get the error "The entity EntityB is not Key value coding-compliant for the key Atta1" Not surprisingly i suppose if i switch things around to fetch from EntityA i cannot access attributes of EntityB So it appears the defined relationshipare being ignored. Can anyone spot what i am doing wrong? I confess im very new to iPhone programming and especially to Core Data so please go easy on me and provide verbose explanations or point me in the direction a specific resource. I have downloaded the apple sample apps (Core Data Books, Top Songs and recipes) but I still can't work this out. Thanks in advance, Nev.

    Read the article

  • WCF Data Services - neither .Expand or .LoadProperty seems to do what I need

    - by TomK
    I am building a school management app where they track student tardiness and absences. I've got three entities to help me in this. A Students entity (first name, last name, ID, etc.); a SystemAbsenceTypes entity with SystemAbsenceTypeID values for Late, Absent-with-Reason, Absent-without-Reason; and a cross-reference table called StudentAbsences (matching the student IDs with the absence-type ID, plus a date, and a Notes field). What I want to do is query my entities for a given student, and then add up the number of each kind of Absence, for a given date range. I prepare my currentStudent object without a problem, then I do this... Me.Data.LoadProperty(currentStudent, "StudentAbsences") 'Loads the cross-ref data lblDaysLate.Text = (From ab In currentStudent.StudentAbsences Where ab.SystemAbsenceTypes.SystemAbsenceTypeID = Common.enuStudentAbsenceTypes.Late).Count.ToString ...and this second line fails, complaining it has no value for an object. I presume the problem is that while it DOES see that there are (let's say) four absences for the currentStudent (ie, currentStudent.StudentAbsences.Count = 4) -- it can't yet "peer into" each one of the absences to look at its type. How do I use .Expand or .LoadProperty to make this happen? I tried fiddling with .LoadProperty but it doesn't take a two-level syntax like so... Data.LoadProperty(currentStudent,"StudentAbsences.SystemAbsenceTypeID") or the like. Is there some other technique?

    Read the article

  • NSUndoManager with Core Data - Redo not working

    - by CJ
    I have a Core Data document-based app which support undo/redo via the built-in NSUndoManager associated with the NSManagedObjectContext. I have a few actions set up which perform numerous tasks within Core Data, wrap all these tasks into an undo group via beginUndoGrouping/endUndoGrouping, and are processed by the NSUndoManager. Undo works fine. I can perform several successive actions, and each then undo each one of them successively and my app's state is maintained correctly. However, the "Redo" menu item is never enabled. This means that the NSUndoManager is telling the menu that there are no items to redo. I am wondering why the NSUndoManager is seemingly forgetting about items once they are undone, and not allowing redos to occur? One thing I should mention is that I'm disabling undo registration after a document is opened/created. When I perform an action, I call enableUndoRegistration, beginUndoGrouping, perform the action, then call processPendingChanges, setActionName:, endUndoGrouping, and finally disableUndoRegistration. This makes sure that only specific actions are undoable, and any other data changes I make outside of these go unnoticed to the NSUndoManager. This may be a part of the issue, but if so I'm wondering why it's affecting redo? Thanks in advance.

    Read the article

  • Regressing panel data in SAS.

    - by John
    Hey Guys, thanks to your help I succesfully managed all my databases! I am now looking at a panel data set on which I have to regress. Since I only started my Phd this semester together with the econometrics courses I am still new to many statistic applications and regression methods. I want to do a simple regression as in Y = x1 x2 x3 etc, now I already browsed through some literature and found that for panel data it's common to do a fixed effects regression. Also, my Y variable only has positive values so I was thinking in the direction of a Tobit model? I'm doing some research concerning the coverage of analysts in the financial business. My independent variable is the coverage of analysts on a certain firm, so per observation i have 1 analyst and 1 firm, together with different characteristics(market cap and betas etc) of the firm. All this data is monthly. As coverage cannot become negative (only 0) I was thinking of a Tobit model? Do you guys have any ideas what would be a good regression method? Or have some good sources (e books, written books, through university I have access to almost anything concerning my field of work) of information (cause I do have to learn these things for future research)? Thanks!

    Read the article

  • Creating LINQ to SQL Data Models' Data Contexts with ASP.NET MVC

    - by Maxim Z.
    I'm just getting started with ASP.NET MVC, mostly by reading ScottGu's tutorial. To create my database connections, I followed the steps he outlined, which were to create a LINQ-to-SQL dbml model, add in the database tables through the Server Explorer, and finally to create a DataContext class. That last part is the part I'm stuck on. In this class, I'm trying to create methods that work around the exposed data. Following the example in the tutorial, I created this: using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace MySite.Models { public partial class MyDataContext { public List<Post> GetPosts() { return Posts.ToList(); } public Post GetPostById(int id) { return Posts.Single(p => p.ID == id); } } } As you can see, I'm trying to use my Post data table. However, it doesn't recognize the "Posts" part of my code. What am I doing wrong? I have a feeling that my problem is related to my not adding the data tables correctly, but I'm not sure. Thanks in advance.

    Read the article

  • Storing high precision latitude/longitude numbers in iOS Core Data

    - by Bryan
    I'm trying to store Latitude/Longitudes in core data. These end up being anywhere from 6-20 digit precision. And for whatever reason, i had them as floats in Core Data, its rounding them and not giving me the exact values back. I tried "decimal" type, with no luck either. Are NSStrings my only other option? EDIT NSManagedObject: @interface Event : NSManagedObject { } @property (nonatomic, retain) NSDecimalNumber * dec; @property (nonatomic, retain) NSDate * timeStamp; @property (nonatomic, retain) NSNumber * flo; @property (nonatomic, retain) NSNumber * doub; Here's the code for a sample number that I store into core data: NSNumber *n = [NSDecimalNumber decimalNumberWithString:@"-97.12345678901234567890123456789"]; Code to access it again: NSNumber *n = [managedObject valueForKey:@"dec"]; NSNumber *f = [managedObject valueForKey:@"flo"]; NSNumber *d = [managedObject valueForKey:@"doub"]; Printed values: Printing description of n: -97.1234567890124 Printing description of f: <CFNumber 0x603f250 [0xfef3e0]>{value = -97.12345678901235146441, type = kCFNumberFloat64Type} Printing description of d: <CFNumber 0x6040310 [0xfef3e0]>{value = -97.12345678901235146441, type = kCFNumberFloat64Type}

    Read the article

  • Pass a data.frame column name to a function

    - by Kevin Middleton
    I'm trying to write a function to accept a data.frame (x) and a column from it. The function performs some calculations on x and later returns another data.frame. I'm stuck on the best-practices method to pass the column name to the function. The two minimal examples fun1 and fun2 below produce the desired result, being able to perform operations on x$column, using max() as an example. However, both rely on the seemingly (at least to me) inelegant (1) call to substitute() and possibly eval() and (2) the need to pass the column name as a character vector. fun1 <- function(x, column){ do.call("max", list(substitute(x[a], list(a = column)))) } fun2 <- function(x, column){ max(eval((substitute(x[a], list(a = column))))) } df <- data.frame(A = 1:20, B = rnorm(10)) fun1(df, "B") fun2(df, "B") I would like to be able to call the function as fun(df, B), for example. Other options I have considered but have not tried: Pass column as an integer of the column number. I think this would avoid substitute(). Ideally, the function could accept either. with(x, get(column)), but, even if it works, I think this would still require substitute Make use of formula() and match.call(), neither of which I have much experience with. Subquestion: Is do.call() preferred over eval()? Thanks, Kevin

    Read the article

  • LOAD DATA INFILE with variables

    - by Hasitha
    I was tring to use the LOAD DATA INFILE as a sotred procedure but it seems it cannot be done. Then i tried the usual way of embedding the code to the application itself like so, conn = new MySqlConnection(connStr); conn.Open(); MySqlCommand cmd = new MySqlCommand(); cmd = conn.CreateCommand(); string tableName = getTableName(serverName); string query = "LOAD DATA INFILE '" + fileName + "'INTO TABLE "+ tableName +" FIELDS TERMINATED BY '"+colSep+"' ENCLOSED BY '"+colEncap+"' ESCAPED BY '"+colEncap+"'LINES TERMINATED BY '"+colNewLine+"' ("+colUpFormat+");"; cmd.CommandText = query; cmd.ExecuteNonQuery(); conn.Close(); The generated query that gets saved in the string variable query is, LOAD DATA INFILE 'data_file.csv'INTO TABLE tbl_shadowserver_bot_geo FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '"'LINES TERMINATED BY '\n' (timestamp,ip,port,asn,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,url,agent,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy); But now when i run the program it gives an error saying, MySQLException(0x80004005) Parameter @dummy must be defined first. I dont know how to get around this, but when i use the same query on mysql itself directly it works fine. PLEASE help me..thank you very much :)

    Read the article

  • Using Constraints on Hierarchical Data in a Self-Referential Table

    - by pbarney
    Suppose you have the following table, intended to represent hierarchical data: +--------+-------------+ | Field | Type | +--------+-------------+ | id | int(10) | | parent | int(10) | | name | varchar(45) | +--------+-------------+ The table is self-referential in that the parent_id refers to id. So you might have the following data: +----+--------+---------------+ | id | parent | name | +----+--------+---------------+ | 1 | 0 | fruit | | 2 | 0 | vegetable | | 3 | 1 | apple | | 4 | 1 | orange | | 5 | 3 | red delicious | | 6 | 3 | granny smith | | 7 | 3 | gala | +----+--------+---------------+ Using MySQL, I am trying to impose a (self-referential) foreign key constraint upon the data to update on cascades and prevent deletion of fruit if they have "children." So I used the following: CREATE TABLE `idtlp_main`.`fruit` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `parent` INT(10) UNSIGNED, `name` VARCHAR(45) NOT NULL, PRIMARY KEY (`id`), CONSTRAINT `fk_parent` FOREIGN KEY (`parent`) REFERENCES `fruit` (`id`) ON UPDATE CASCADE ON DELETE RESTRICT ) ENGINE = InnoDB; From what I understand, this should fit my requirements. (And parent must default to null to allow insertions, correct?) The problem is, if I change the id of a record, it will not cascade: Cannot delete or update a parent row: a foreign key constraint fails (`iddoc_main`.`fruit`, CONSTRAINT `fk_parent` FOREIGN KEY (`parent`) REFERENCES `fruit` (`id`) ON UPDATE CASCADE) What am I missing? Feel free to correct me if my terminology is screwed up... I'm new to constraints.

    Read the article

< Previous Page | 53 54 55 56 57 58 59 60 61 62 63 64  | Next Page >