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  • Deploying App With Dummy/Initial Data

    - by mattmccomb
    I have a Core Data based application that stores hierarchal data displayed using a series of UITableViews. To illustrate my app functionality to the user I would like to pre-populate my database/app with some dummy values. This data would be available upon installation on the user's iPhone/iPod Touch. What is the best way to achieve this?

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  • Load SQL query result data into cache in advance

    - by Marc
    I have the following situation: .net 3.5 WinForm client app accessing SQL Server 2008 Some queries returning relatively big amount of data are used quite often by a form Users are using local SQL Express and restarting their machines at least daily Other users are working remotely over slow network connections The problem is that after a restart, the first time users open this form the queries are extremely slow and take more or less 15s on a fast machine to execute. Afterwards the same queries take only 3s. Of course this comes from the fact that no data is cached and must be loaded from disk first. My question: Would it be possible to force the loading of the required data in advance into SQL Server cache? Note My first idea was to execute the queries in a background worker when the application starts, so that when the user starts the form the queries will already be cached and execute fast directly. I however don't want to load the result of the queries over to the client as some users are working remotely or have otherwise slow networks. So I thought just executing the queries from a stored procedure and putting the results into temporary tables so that nothing would be returned. Turned out that some of the result sets are using dynamic columns so I couldn't create the corresponding temp tables and thus this isn't a solution. Do you happen to have any other idea?

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  • Using Parameter Values In SQL Statement

    - by Dangerous
    I am trying to write a database script (SQL SERVER 2008) which will copy information from database tables on one server to corresponding tables in another database on a different server. I have read that the correct way to do this is to use a sql statement in a format similar to the following: INSERT INTO <linked_server>.<database>.<owner>.<table_name> SELECT * FROM <linked_server>.<database>.<owner>.<table_name> As there will be several tables being copied, I would like to declare variables at the top of the script to allow the user to specify the names of each server and database that are to be used. These could then be used throughout the script. However, I am not sure how to use the variable values in the actual SQL statements. What I want to achieve is something like the following: DECLARE @SERVER_FROM AS NVARCHAR(50) = 'ServerFrom' DECLARE @DATABASE_FROM AS NVARCHAR(50) = 'DatabaseTo' DECLARE @SERVER_TO AS NVARCHAR(50) = 'ServerTo' DECLARE @DATABASE_TO AS NVARCHAR(50) = 'DatabaseTo' INSERT INTO @SERVER_TO.@DATABASE_TO.dbo.TableName SELECT * FROM @SERVER_FROM.@DATABASE_FROM.dbo.TableName ... How should I use the @ variables in this code in order for it to work correctly? Additionally, do you think my method above is correct for what I am trying to achieve and should I be using NVARCHAR(50) as my variable type or something else? Thanks

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  • Choose a XML node in SQL Server based on max value of a child element

    - by Jay
    I am trying to select from SQL Server 2005 XML datatype some values based on the max data that is located in a child node. I have multiple rows with XML similar to the following stored in a field in SQL Server: <user> <name>Joe</name> <token> <id>ABC123</id> <endDate>2013-06-16 18:48:50.111</endDate> </token> <token> <id>XYX456</id> <endDate>2014-01-01 18:48:50.111</endDate> </token> </user> I want to perform a select from this XML column where it determines the max date within the token element and would return the datarows similar to the result below for each record: Joe XYZ456 2014-01-01 18:48:50.111 I have tried to find a max function for xpath that would all me to select the correct token element but I couldn't find one that would work. I also tried to use the SQL MAX function but I wasn't able to get it working with that method either. If I only have a single token it of course works fine but when I have more than one I get a NULL, most likely because the query doesn't know which date to pull. I was hoping there would be a way to specify a where clause [max(endDate)] on the token element but haven't found a way to do that. Here is an example of the one that works when I only have a single token: SELECT XMLCOL.query('user/name').value('.','NVARCHAR(20)') as name XMLCOL.query('user/token/id').value('.','NVARCHAR(20)') as id XMLCOL.query('user/token/endDate').value(,'xs:datetime(.)','DATETIME') as endDate FROM MYTABLE

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  • don't wanna lose data on Android after uninstalling

    - by soclose
    Hi, Now I make a trial application. I'd like to store IMEI and other info in Android permanently. And I don't want to lose them after uninstalling it. I tested with shared preference but it deletes after un-installation. SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0); SharedPreferences.Editor editor = settings.edit(); editor.putBoolean("silentMode", true); // Commit the edits! editor.commit(); let me know where to store.

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  • Performance impact when using XML columns in a table with MS SQL 2008

    - by Sam Dahan
    I am using a simple table with 6 columns, 3 of which are of XML type, not schema-constrained. When the table reaches a size around 120,000 or 150,000 rows, I see a dramatic performance cost in doing any query in the table. For comparison, I have another table, which grows in size at about the same rate, but only contain scalar types (int, datetime, a few float columns). That table performs perfectly fine even after 200,000 rows. And by the way, I am not using XQuery on the xml columns, i am only using regular SQL query statements. Some specifics: both tables contain a DateTime field called SampleTime. a statement like (it's in a stored procedure but I show you the actual statement) SELECT MAX(sampleTime) SampleTime FROM dbo.MyRecords WHERE PlacementID=@somenumber takes 0 seconds on the table without xml columns, and anything from 13 to 20 seconds on the table with XML columns. That depends on which drive I set my database on. At the moment it sits on a different spindle (not C:) and it takes 13 seconds. Has anyone seen this behavior before, or have any hint at what I am doing wrong? I tried this with SQL 2008 EXPRESS and the full-blown SQL Server 2008, that made no difference. Oh, one last detail: I am doing this from a C# application, .NET 3.5, using SqlConnection, SqlReader, etc.. I'd appreciate some insight into that, thanks! Sam

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  • SSIS Transaction with Sql Transaction

    - by Mike
    I started with a package to make sure Transactions are working correctly. The package level transaction is set to Required. I have two Execute Sql Task, one deletes rows from a table and one does 1/0, to throw the error. Both task are set to supported transaction level and Serializable IsolationLevel. That works. Now when I replace my two sql task to two separate procedure calls, the first one, ChargeInterest, runs successful but the second one, PaymentProcess, fails always saying. [Execute SQL Task] Error: Executing the query "Exec [proc_xx_NotesReceivable_PaymentProcess] ..." failed with the following error: "Uncommittable transaction is detected at the end of the batch. The transaction is rolled back.". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly. PaymentProcess being the second stored procedure. Both procedures have there own BEGIN, COMMIT AND ROLLBACKS inside the SP. I believe that the transactions are being successfully handed in the Charge Interest because I can run the following without issues or the dreaded you started with 0 and now have 1 transaction. EXEC [proc_XX_NotesReceivable_ChargeInterest] 'NR', 'M', 186, 300 EXEC [proc_XX_NotesReceivable_PaymentProcess] 'NR', 186, 300 --OR GO BEGIN TRAN EXEC [proc_XX_NotesReceivable_ChargeInterest] 'NR', 'M', 186, 300 EXEC [proc_XX_NotesReceivable_PaymentProcess] 'NR', 186, 300 ROLLBACK TRAN Now I have noticed that DTC does get kicked off in both instances? Why I am not sure because it is using the same connection. In the live example I can see the transaction get started but disappears if I put a breakpoint on the PreExecute event of the second stored procedure. What is the correct way to mingle SP transactions with SSIS transactions?

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  • Linq to SQL code generator features

    - by Anders Abel
    I'm very fond of Linq to SQL and the programming model it encourages. I think that in many cases when you are in control of both the database schema and the code it is not worth the effort to have different relational and object models for the data. Working with Linq to SQL makes it simple to have type safe data access from .NET, using the partial extension methods to implement business rules. Unfortunately I do not like the dbml designer due to the lack of a schema refresh function. So far I have used SqlMetal, but that lacks the customization options of the dbml designer. Because of that I've started working on a tool which regenerates the whole code file like SqlMetal, but has the ability to do the customizations that are available in the dbml designer (and maybe more in the future). The customizations will be described in an xml file which only contains those parts that shouldn't have default values. This should keep the xml file size down as well as the maintenance burden of it. To help me focus on the right features, I would like to know: What would be your favourite feature in a linq to sql code generator?

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  • how to split a very large database on sql server

    - by ken jackson
    I have a 90 GB SQL Server database that I want to make more manageable. It stores stock data from 50+ different stocks from 2009 and 2010, and each stock is a separate table. Some tables have hundreds of millions of rows, and other have just a few million. What I want to do is somehow split the database, so that I don't have a single database file that is 90 GB. What I want is to be able to somehow magically split all the tables so that I can backup the 2009 data once and not have to keep on including it in the backup every time I backup the entire database, however, I would like the 2009 data to be included whenever I do a query. Is partitioning the database the way to go? Will it do the above for me, or will I need some other solution? I research partitioning, but I wasn't sure if that would solve all my problems. I wasn't able to find anything that would tell me whether or not it would migrate prexisting data, or whether it only worked for newly inserted data. Any help or pointers would be much appreciated. Thanks in advance, Ken

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  • Import data from .xls File

    - by tek3
    HI, I am developing an application in which i have to get data from .xls file. I am fairly new to iPhone development so any pointers in direction to getting started will be very much helpful. The steps that i am thinking are : 1) First i need to convert .xls to .csv Format. 2)Import the data from .csv file to SQlite Databse or Core Data.(I am not familier with any one of them, so kindly suggest which one to choose. I am looking forward to use Core Data) Am I thinking in the right direction. Will be greatful for any kind of assistance.. Thanx in advance..

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  • SQL string manipulation to return multiple rows

    - by Andy Jacobs
    I'm an experienced programmer, but relatively new to SQL. We're using Oracle 10 and 11. I have a system in place using SQL that combines actual rows with virtual rows (e.g. "SELECT 1 from DUAL") doing unions and intersects as needed, which all seems to work. My problem is that I need to combine this system which is expecting rows of data, with new data that will have the data in (let's say for simplification) comma delimited strings. So I think what I need is a way to convert a string like: "5,6,7,8" into 4 rows with one column each, with "5" in the first row, "6" in the second, etc. In other languages, I'd do a "Split" with comma as the delimiter. Of course, the data won't always have 4 entries. There's a second question, but I'll ask it separately. But I suspect it will simplify things, if possible, if the solution to the above could be used as a table in another SQL statement (i.e., to work with my existing system). Thanks for any help.

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  • Data munging and data import scripting

    - by morpheous
    I need to write some scripts to carry out some tasks on my server (running Ubuntu server 8.04 TLS). The tasks are to be run periodically, so I will be running the scripts as cron jobs. I have divided the tasks into "group A" and "group B" - because (in my mind at least), they are a bit different. Task Group A import data from a file and possibly reformat it - by reformatting, I mean doing things like santizing the data, possibly normalizing it and or running calculations on 'columns' of the data Import the munged data into a database. For now, I am mostly using mySQL for the vast majority of imports - although some files will be imported into a sqlLite database. Note: The files will be mostly text files, although some of the files are in a binary format (my own proprietary format, written by a C++ application I developed). Task Group B Extract data from the database Perform calculations on the data and either insert or update tables in the database. My coding experience is is primarily as a C/C++ developer, although I have been using PHP as well for the last 2 years or so. I am from a windows background so I am still finding my feet in the linux environment. My question is this - I need to write scripts to perform the tasks I described above. Although I suppose I could write a few C++ applications to be used in the shell scripts, I think it may be better to write them in a scripting language (maybe this is a flawed assumption?). My thinking is that it would be easier to modify thins in a script - no need to rebuild etc for changes to functionality. Additionally, C++ data munging in C++ tends to involve more lines of code than "natural" scripting languages such as Perl, Python etc. Assuming that the majority of people on here agree that scripting is the way to go, herein lies my dilema. Which scripting language to use to perform the tasks above (giving my background). My gut instinct tells me that Perl (shudder) would be the most obvious choice for performing all of the above tasks. BUT (and that is a big BUT). The mere mention of Perl makes my toes curl, as I had a very, very bag experience with it a while back. The syntax seems quite unnatural to me - despite how many times I have tried to learn it - so if possible, I would really like to give it a miss. PHP (which I already know), also am not sure is a good candidate for scripting on the CLI (I have not seen many examples on how to do this etc - so I may be wrong). The last thing I must mention is that IF I have to learn a new language in order to do this, I cannot afford (time constraint) to spend more than a day, in learning the key commands/features required in order to do this (I can always learn the details of the language later, once I have actually deployed the scripts). So, which scripting language would you recommend (PHP, Python, Perl, [insert your favorite here]) - and most importantly WHY?. Or, should I just stick to writing little C++ applications that I call in a shell script?. Lastly, if you have suggested a scripting language, can you please show with a FEW lines (Perl mongers - I'm looking in your direction [nothing to cryptic!] ;) ) how I can use the language you suggested to do what I want to do. Hopefully, the lines you present will convince me that it can be done easily and elegantly in the language you suggested.

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  • Performance of VIEW vs. SQL statement

    - by Matt W.
    I have a query that goes something like the following: select <field list> from <table list> where <join conditions> and <condition list> and PrimaryKey in (select PrimaryKey from <table list> where <join list> and <condition list>) and PrimaryKey not in (select PrimaryKey from <table list> where <join list> and <condition list>) The sub-select queries both have multiple sub-select queries of their own that I'm not showing so as not to clutter the statement. One of the developers on my team thinks a view would be better. I disagree in that the SQL statement uses variables passed in by the program (based on the user's login Id). Are there any hard and fast rules on when a view should be used vs. using a SQL statement? What kind of performance gain issues are there in running SQL statements on their own against regular tables vs. against views. (Note that all the joins / where conditions are against indexed columns, so that shouldn't be an issue.) EDIT for clarification... Here's the query I'm working with: select obj_id from object where obj_id in( (select distinct(sec_id) from security where sec_type_id = 494 and ( (sec_usergroup_id = 3278 and sec_usergroup_type_id = 230) or (sec_usergroup_id in (select ug_gi_id from user_group where ug_ui_id = 3278) and sec_usergroup_type_id = 231) ) and sec_obj_id in ( select obj_id from object where obj_ot_id in (select of_ot_id from obj_form left outer join obj_type on ot_id = of_ot_id where ot_app_id = 87 and of_id in (select sec_obj_id from security where sec_type_id = 493 and ( (sec_usergroup_id = 3278 and sec_usergroup_type_id = 230) or (sec_usergroup_id in (select ug_gi_id from user_group where ug_ui_id = 3278) and sec_usergroup_type_id = 231) ) ) and of_usage_type_id = 131 ) ) ) ) or (obj_ot_id in (select of_ot_id from obj_form left outer join obj_type on ot_id = of_ot_id where ot_app_id = 87 and of_id in (select sec_obj_id from security where sec_type_id = 493 and ( (sec_usergroup_id = 3278 and sec_usergroup_type_id = 230) or (sec_usergroup_id in (select ug_gi_id from user_group where ug_ui_id = 3278) and sec_usergroup_type_id = 231) ) ) and of_usage_type_id = 131 ) and obj_id not in (select sec_obj_id from security where sec_type_id = 494) )

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  • Which SQL statements to execute with intersection / junction tables

    - by user1455103
    Here a simplified database layout One condo can hold multiple properties (flats, garage boxes, etc) - 1->n relationship One owner can have multiple properties in the same condo and properties can have more than one owner (m->n changed to 1->n with the junction table) One condo can have multiple owners - 1->n Some additional clarification: A owner is a member of a condo. A condo is made of properties belonging to owners BUT a owner is not linked to a property directly (there can be no relation between a property and a owner for a certain time BUT there will ALWAYS be a relation between a owner and a condo). Reason for this: the agent managing the condo will first create a list of owners and a list of properties. It is only later thet he will "link" each property to one or multiple owners (or inversely) I'm quite new to SQL. What SQL statements should I execute to: SELECT, for a specific condo (WHERE condition), the properties and their respective owners (all properties should be listed even if owners are null) SELECT, for a specific condo (WHERE condition), the owners along with their properties (all owners should be listed even if properties are null) UPDATE / DELETE existing owners (I'm uncertain about how to handle the operation for the junction tables. Should I first check if there is an entry in the junction table or not ?) UPDATE / DELETE existing properties (same concern) INSERT new owners (should I use two different SQL statements depending if the owner should be linked to a property or NOT - IF condition ?) INSERT new properties (same question as above) Could you be as clear and generic as possible so that it can be reused ? :-)

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  • Is it possible to definitively identify whether a DML command was issued from a stored procedure?

    - by Ed Harper
    I have inherited a SQL Server 2008 database to which calling applications have access through stored procedures. Each table in the database has a shadow audit table into which Insert/Update/Delete operations for are logged. Performance testing on populating the audit tables showed that inserting the audit records using OUTPUT clauses was 20% or so faster than using triggers, so this has been implemented in the stored procedures. However, because this design cannot track changes made directly to the tables through DML statements issued directly against the tables, triggers have also been implemented which use the value of @@NESTLEVEL to determine whether or not to run the trigger (the assumption being that all DML run through stored procedures will have @@NESTLEVEL 1). i.e. the body of the trigger code looks something like: IF @@NESTLEVEL = 1 -- implies call is direct sql so generate history from here BEGIN ... insert into audit table This design is flawed because it won't track updates where DML statements are executed in dynamic SQL, or any other context where @@NESTLEVEL is raised above 1. Can anyone suggest a completely reliable method we can use in the triggers to execute them only if not triggered by a stored procedure? Or is this (as I suspect) not possible?

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  • Handling missing/incomplete data in R

    - by doug
    As you would expect from a DSL aimed at data analysts, R handles missing/incomplete data very well, for instance: Many R functions have an 'na.rm' flag that you can set to 'T' to remove the NAs, but if you want to deal with this before the function call, then: to replace each 'NA' w/ 0: ifelse(is.na(vx), 0, vx) to remove each 'NA': vx = vx[!is.na(a)] to remove entire each row that contains 'NA' from a data frame: dfx = dfx[complete.cases(dfx),] All of these functions remove 'NA' or rows with an 'NA' in them. Sometimes this isn't quite what you want though--making an 'NA'-excised copy of the data frame might be necessary for the next step in the workflow but in subsequent steps you often want those rows back (e.g., to calculate a column-wise statistic for a column that has missing rows caused by a prior call to 'complete cases' yet that column has no 'NA' values in it). to be as clear as possible about what i'm looking for: python/numpy has a class, 'masked array', with a 'mask' method, which lets you conceal--but not remove--NAs during a function call. Is there an analogous function in R?

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  • ways to store data in c#

    - by Audel
    I am looking for ways to store data in a windows form application in C#. I want to make the input data of a system persistent, so when I close my program and open it again, the data is retrieved. Which ways are of doing this besides creating a linked database? Examples are gladly appreciated regards

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  • Migrate Data and Schema from MySQL to MSSQL

    - by colithium
    Are there any free solutions for automatically migrating a database from MySQL to MSSQL Server that "just works"? I've been attempting this simple (at least I thought so) task all day now. I've tried: MSSQL Server Management Studio's Import Data feature Create an empty database Tasks - Import Data... .NET Framework Data Provider for Odbc Valid DSN (verified it connects) Copy data from one or more tables or views Check 1 VERY simple table Click Preview Get Error: The preview data could not be retrieved. ADDITIONAL INFORMATION: ERROR [42000] [MySQL][ODBC 5.1 Driver][mysqld-5.1.45-community]You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '"table_name"' at line 1 (myodbc5.dll) A similar error occurs if I go through the rest of the wizard and perform the operation. The failed step is "Setting Source Connection" the error refers to retrieving column information and then lists the above error. It can retrieve column information just fine when I modify column mappings so I really don't know what the issue is. I've also tried getting various MySql tools to output ddl statements that MSSQL understand but haven't succeeded. I've tried with MySQL v5.1.11 to SQL Server 2005 and with MySQL v5.1.45 to SQL Server 2008 (with ODBC drivers 3.51.27.00 and 5.01.06.00 respectively)

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  • SQL Server log backups "stalling"

    - by MattK
    I have interited a box running SQL Server 2008 and Windows 2003, and have had a few events where largeish (35GB) log backups "stall", both before and after the installation of SQL 2008 SP1. The server log ships to a standby, so regular log backups are taken at 15 minute intervals. However, after an index reorg causes the log to grow to about 35GB (on a DB with about 17GB of data), the next log backup runs to ~95% completion, then seems to stop. The process shows as suspended, with a wait state of BACKUPIO. CPU, read, and write activity on the SPID also does not change, and the process stays in this state for hours, when normally a backup of this size should complete in about 20 minutes. This server has a single RAID-1 volume, thus the source database files and destination backup files are on the same volume. However, I cannot determine if another process is blocking the backup. The backup SPID cannot be killed, and the only way to terminate the log backup and clear the lock on the backup file is to cycle the SQL Server service. There was one event where the backup terminated completely, with an error that another process had locked the backup file, but no details about what that process was. Can anyone suggest a cause or diagnostic process to this situation?

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  • Using R to download zipped data file, extract, and import data

    - by Jeromy Anglim
    @EZGraphs on Twitter writes: "Lots of online csvs are zipped. Is there a way to download, unzip the archive, and load the data to a data.frame using R? #Rstats" I was also trying to do this today, but ended up just downloading the zip file manually. I tried something like: fileName <- "http://www.newcl.org/data/zipfiles/a1.zip" con1 <- unz(fileName, filename="a1.dat", open = "r") but I feel as if I'm a long way off. Any thoughts?

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  • function to find common rows between more than two data frames in R

    - by biohazard
    I have 4 data frames, and would like to find the rows whose values in a certain column do not exist in any of the other data frames. I wrote this function: #function to test presence of $Name in 3 other datasets common <- function(a, b, c, d) { is.B <- is.numeric(a$Name %in% b$Name) == 1 is.C <- is.numeric(a$Name %in% c$Name) == 1 is.D <- is.numeric(a$Name %in% d$Name) == 1 t <- as.numeric(is.B & is.C & is.D) t } However, the output is always t = 0. This means that it tells me that there are no unique rows in any data sets, even though the datas frames have very different numbers of rows. Since there are no duplicate rows in any of the data frames, I should be getting t = 1 for at least some rows in the biggest dataset. Can someone figure out what I got wrong?

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  • JSON parse data in javascript from php

    - by Stefania
    I'm trying to retrieve data in a javascript file from a php file using json. $items = array(); while($r = mysql_fetch_array($result)) { $rows = array( "id_locale" => $r['id_locale'], "latitudine" => $r['lat'], "longitudine" => $r['lng'] ); array_push($items, array("item" => $rows)); } ECHO json_encode($items); and in the javascript file I try to recover the data using an ajax call: $.ajax({ type:"POST", url:"Locali.php", success:function(data){ alert("1"); //var obj = jQuery.parseJSON(idata); var json = JSON.parse(data); alert("2"); for (var i=0; i<json.length; i++) { point = new google.maps.LatLng(json[i].item.latitudine,json[i].item.longitudine); alert(point); } } }) The first alert is printed, the latter does not, it gives me error: Unexpected token <.... but I do not understand what it is. Anyone have any idea where am I wrong? I also tried to recover the data with jquery but with no positive results.

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  • Detaching all entities of T to get fresh data

    - by Goran
    Lets take an example where there are two type of entites loaded: Product and Category, Product.CategoryId - Category.Id. We have available CRUD operations on products (not Categories). If on another screen Categories are updated (or from another user in the network), we would like to be able to reload the Categories, while preserving the context we currently use, since we could be in the middle of editing data, and we do not want changes to be lost (and we cannot depend on saving, since we have incomplete data). Since there is no easy way to tell EF to get fresh data (added, removed and modified), we thought of twp possible ways: 1) Getting products attached to context, and categories detached from context. This would mean that we loose the ability to access Product.Category.Name, which we do sometimes require, so we would need to manually resolve it (example when printing data). 2) detaching / attaching all Categories from current context. Context.ChangeTracker.Entries().Where(x => x.Entity.GetType() == typeof(T)).ForEach(x => x.State = EntityState.Detached); And then reload the categories, which will get fresh data. Do you find any problem with this second approach? We understand that this will require all constraints to be put on foreign keys, and not navigation properties, since when detaching all Categories, Product.Category navigation properties would be reset to null also. Also, there could be a potential performance problem, which we did not test, since there could be couple of thousand products loaded, and all would need to resolve navigation property when reloading. Which of the two do you prefer, and is there a better way (EF6 + .NET 4.0)?

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  • Strategies for "Always-Connected" Windows Client Data Architecture

    - by magz2010
    Hi. Let me start by saying: this is my 1st post here, this is a bit lenghty, and I havent done Windows Forms development in years....with that in mind please excuse me if this isn't directly a programming question and please bear with me as I really need the help!! I have been asked to develop a Windows Forms app for our company that talks to a central (local area network) Linux Server hosting a PostgreSQL database. The app is to allow users to authenticate themselves into the system and thereafter conduct the usual transactions with the PG database. Ordinarily, I would propose writing a webforms app against Mono, but the clients need to utilise local resources such as USB peripheral devices, so that is out of the question. While it might not seem clear, my questions are italised below: Dilemma #1: The application is meant to be always connected. How should I structure my DAL/BLL - Should this reside on the server or with the client? Dilemma #2: I have been reading up on Client Application Services (CAS), and it seems like a great fit for authentication, as everything is exposed via URIs. I know that a .NET Data Provider exists for PostgreSQL, but not too sure if CAS will all work on a Linux (Debian) server? Believe me, I would get my hands dirty and try myself, but I need to come up with a logical design first before resources are allocated to me for "trial purposes"! Dilemma #3: If the DAL/BLL is to reside on the server, is there any way I can create data services, and expose only these services to authenticated clients. There is a (security) requirement whereby a connection string with username and password to the database cannot be present on any client machines...even if security on the database side is quite rigid. I'm guessing that the only way for this to work would be to create the various CRUD data service methods that are exposed by an ASP.NET app, and have the WindowsForms make a request for data or persist data to the ASP.NET app (thru a URI) and have that return a resultset or value. Would I be correct in assuming this? Should I be looking into WCF Data Services? and will WCF work with a non-SQL Server database? Thank you for taking the time out to read this, but know that I am desperately seeking any advice on this! THANKS A MILLION!!!!

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