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  • How can I use AND condition in IF EXISTS in SQL?

    - by user811433
    IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'X' AND COLUMN_NAME = 'Y') IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'Z' AND COLUMN_NAME = 'A') BEGIN UPDATE [dbo].[X] SET Y= (SELECT inst.[A] FROM [dbo].[Z] s WHERE s.[B] = [dbo].[x].[B]); END GO I want to combine the 2 IF confitions and perform the update only when both of them are satisfied. Is there some way in which I can club 2 IF EXISTS?

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  • What could cause my LAN Pings be greater than 100ms?

    - by James Holland
    I have 2 servers (Both: Windows Server 2008, Dual Xeon 2.8Ghz, 32GB RAM, 8 x 15k SAS Drives). One of them is a DC / Web server / Exchange Server, the other is a SQL Server (2008). I have a 48 port Netgear GS748T Gigabit switch. When I ping from server to server, I get ping times <1ms, great, but when I ping from a PC, I get varying pings from the occasional <1ms to 500ms!! If I log into either server and look at Task Manager, CPU usage peaks at 20%, memory usage is 100%, but I am led to believe this is normal as Exchange will just use as much as you have, and release it when requested. Network usage peaks at 1%. I really don't understand how the ping can vary that much. I know I am giving very little info, but this is all I know, I apologise, but can anyone help? In response to question, I have pinged by both IP address and hostname, no difference in ping times.

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  • Drive configuration for 5 large databases

    - by Mr. Flibble
    I've got 5 databases, each 300GB, currently on a RAID 5 array consisting of 5 drives. All the databases are used heavily, at the same time, so drive speed is an issue. Would I see better performance if I got rid of the RAID 5 configuration and just put each database on a separate drive? The redundancy provided by RAID 5 is not necessary due to mirroring elsewhere. Will the server then be able to perform reads / writes to different databases drives in parallel? More so at least than when it's in RAID? This is all on Windows 2003 / SQL 2008.

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  • Database mirroring login failure attempts on mirror server

    - by Chandan
    I have configured database mirroring between two servers at a distance 40 miles away from each other. Server specifications: SQL Server 2008,Standard Edition 64-bit This is same for principal,mirror and witness. The configuration is high-safety with automatic failover Initially we tested our .net application(web application) on both the principal and mirror and made sure that the login is not orpahned. Things run fine generally.But sometimes on the mirror server,I see login failed attempts: Login failed for user 'd0main\user'. Reason: Failed to open the explicitly specified database. [CLIENT: xx.xx.x.x] Message Error: 18456, Severity: 14, State: 38. This error appears 3-4 times a day but not more than that. My question to the experts is:If the principal is alive so why the application tries to connect to mirror.The default time-out for a .net webpage is 30 seconds,so is it possible that the application tries to connect principal and after 30 seconds even if principal is alive,it assumes that it is dead and thus tries to open a connection to mirror where it fails. Please help me with this problem.

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  • SQL Server Table locks in long query - Solution: NoLock?

    - by Kovu
    a report in my application runs a query that needs between 5 - 15 seconds (constrained to count of rows that will be returned). The query has 8 joins to nearly all main-tables of my application (Customers, sales, units etc). A little tool shows me, that in this time, all those 8 tables are locked with a shared table lock. That means, no update operation will be done in this time. A solution from a friend is, to have every join in the query, which is not mandetory to have 100% correct data (dirty read), with a NoLock, so only 1 of this 8 tables will be locked completly. Is that a good solution? For a report in which 99% of data came from one table, unlock the less prio tables?

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  • Microsoft OLE DB Provider for SQL Server error '80040e14' Could not find stored procedure

    - by BBlake
    I am migrating a classic ASP web app to new servers. The database back end is migrating from SQL Server 2000 to SQL Server 2008, and the app is moving from Win2000 x86 to Win2003R2 x64. I am getting the above error on every single stored procedure call within the application. I have verified: Yes, the SQL user is set up, using correct username and password Yes, the SQL user has execute permissions on the stored procedures in the database Yes, I have updated the TypeLib references to the new UUID Yes, I have logged into the database via SSMS with the SQL user id and it can see and execute the stored procedures just fine in SSMS, but not from the web app. Yes, the SQL user has the database set as its default database. The most frustrating thing is it works fine on the DEV server, but not on the production server. I have gone through every IIS setting 5 or 6 times and the web app is set up precisely the same in both environments. The only difference is the database server name in the connection string (DEV vs prod) EDIT: I have also tried pointing the prod web box at the dev database server and get the same error so I'm fairly sure the issue isn't on the database side.

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  • How to put foreign key constraints on a computed fields in sql server?

    - by Asaf R
    Table A has a computed field called Computed1. It's persisted and not null. Also, it always computes to an expression which is char(50). It's also unique and has a unique key constraint on it. Table B has a field RefersToComputed1, which should refer to a valid Computed1 value. Trying to create a foreign key constraint on B's RefersToComputed1 that references A' Computed1 leads to the following error: Error SQL01268: .Net SqlClient Data Provider: Msg 1753, Level 16, State 0, Line 1 Column 'B.RefersToComputed1' is not the same length or scale as referencing column 'A.Computed1' in foreign key 'FK_B_A'. Columns participating in a foreign key relationship must be defined with the same length and scale. Q: Why is this error created? Are there special measures needed for foreign keys for computed columns, and if so what are they? Summary: The specific problem rises from computed, char based, fields being varchar. Hence, Computed1 is varchar(50) and not char(50). It's best to have a cast surrounding a computed field's expression to force it to a specific type. Credit goes to Cade Roux for this tip.

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  • unit/integration testing web service proxy client

    - by cori
    I'm rewriting a PHP client/proxy library that provides an interface to a SOAP-based .Net webservice, and in the process I want to add some unit and integration tests so future modifications are less risky. The work the library I'm working on performs is to marshall the calls to the web service and do a little reorganizing of the responses to present a slightly more -object-oriented interface to the underlying service. Since this library is little else than a thin layer on top of web service calls, my basic assumption is that I'll really be writing integration tests more than unit tests - for example, I don't see any reason to mock away the web service - the work that's performed by the code I'm working on is very light; it's almost passing the response from the service right back to its consumer. Most of the calls are basic CRUD operations: CreateRole(), CreateUser(), DeleteUser(), FindUser(), &ct. I'll be starting from a known database state - the system I'm using for these tests is isolated for testing purposes, so the results will be more or less predictable. My question is this: is it natural to use web service calls to confirm the results of operations within the tests and to reset the state of the application within the scope of each test? Here's an example: One test might be createUserReturnsValidUserId() and might go like this: public function createUserReturnsValidUserId() { // we're assuming a global connection to the service $newUserId = $client->CreateUser("user1"); assertNotNull($newUserId); assertNotNull($client->FindUser($newUserId); $client->deleteUser($newUserId); } So I'm creating a user, making sure I get an ID back and that it represents a user in the system, and then cleaning up after myself (so that later tests don't rely on the success or failure of this test w/r/t the number of users in the system, for example). However this still seems pretty fragile - lots of dependencies and opportunities for tests to fail and effect the results of later tests, which I definitely want to avoid. Am I missing some options of ways to decouple these tests from the system under test, or is this really the best I can do? I think this is a fairly general unit/integration testing question, but if it matters I'm using PHPUnit for the testing framework.

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  • Just Another Web Service (JAWS) vs SOA

    Over the last few years SOA has been a hot topic lending it to be abused by many that have no understanding of the concept. In my opinion, one of the largest issues facing SOA is the lack of understanding and experience implementing SOA by business and IT alike. I just recently deployed a new web services that is called by multiple service clients. Would you call this SOA because it is a web service that can be called by any requesting client? In my opinion, this is not SOA; instead it is Just Another Web Service (JAWS).  Just because a company creates a web service does not mean that they are using SOA, in fact it only means that they are using a web service. SOA is an architectural style that focuses on the design of systems based on the consumer and providers thorough the use of contracts.  With this approach SOA needs to be applied for the top down in order for it to reach its full potential. In the case of the web service, the service is just a small part of the entire system that is reusable and has the flexibility to change. In order for a company in this case to move towards SOA then they need to define business processes that can be shared through the use of reusable software and loose coupling. Once the company’s thought and development process change to address changes in this manner they can start to become more SOA.

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  • How to write to a varchar(max) column using ODBC

    - by andyjohnson
    Summary: I'm trying to write a text string to a column of type varchar(max) using ODBC and SQL Server 2005. It fails if the length of the string is greater than 8000. Help! I have some C++ code that uses ODBC (SQL Native Client) to write a text string to a table. If I change the column from, say, varchar(100) to varchar(max) and try to write a string with length greater than 8000, the write fails with the following error [Microsoft][ODBC SQL Server Driver]String data, right truncation So, can anyone advise me on if this can be done, and how? Some example (not production) code that shows what I'm trying to do: SQLHENV hEnv = NULL; SQLRETURN iError = SQLAllocEnv(&hEnv); HDBC hDbc = NULL; SQLAllocConnect(hEnv, &hDbc); const char* pszConnStr = "Driver={SQL Server};Server=127.0.0.1;Database=MyTestDB"; UCHAR szConnectOut[SQL_MAX_MESSAGE_LENGTH]; SWORD iConnectOutLen = 0; iError = SQLDriverConnect(hDbc, NULL, (unsigned char*)pszConnStr, SQL_NTS, szConnectOut, (SQL_MAX_MESSAGE_LENGTH-1), &iConnectOutLen, SQL_DRIVER_COMPLETE); HSTMT hStmt = NULL; iError = SQLAllocStmt(hDbc, &hStmt); const char* pszSQL = "INSERT INTO MyTestTable (LongStr) VALUES (?)"; iError = SQLPrepare(hStmt, (SQLCHAR*)pszSQL, SQL_NTS); char* pszBigString = AllocBigString(8001); iError = SQLSetParam(hStmt, 1, SQL_C_CHAR, SQL_VARCHAR, 0, 0, (SQLPOINTER)pszBigString, NULL); iError = SQLExecute(hStmt); // Returns SQL_ERROR if pszBigString len > 8000 The table MyTestTable contains a single colum defined as varchar(max). The function AllocBigString (not shown) creates a string of arbitrary length. I understand that previous versions of SQL Server had an 8000 character limit to varchars, but not why is this happening in SQL 2005? Thanks, Andy

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  • SQL Server 2008 - Login failed for user 'user1' The user is not associated with a trusted SQL Server connection

    - by difek
    I have installed SQL Server 2008 R2 on Windows XP. In installation process I selected 'SQL Server and Windows Authentication Mode' When I click right button of the mouse in SQL Server Management Studio on Server - Security tab 'SQL server and Windows Authentication Mode' is selected. But when I click on my Database - Properties - View connection properties Authentication Method is set on Windows Authentication. To my database was added one user1 with password user1. But I can't log in to my database from C# (Visual Studio 2008) because error occurs: Login failed for user 'user1' The user is not associated with a trusted SQL Server connection What isn't right ? When I get: string connectionStr = @"Data Source=rmzcmp\SQLExpress;Initial Catalog=ResourcesTmp;Integrated Security=True"; I have following error: {"Cannot open database \"ResourcesTmp\" requested by the login. The login failed.\r\nLogin failed for user 'RMZCMP\rm'."} rm is my original user name on which I log in to my computer. When I get rm I have error: {"Login failed for user 'rm'. The user is not associated with a trusted SQL Server connection."} again. Regards

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  • SQL 2005 Express Edition - Install new instance

    - by Douglas Anderson
    Looking for a way to programatically, or otherwise, add a new instance of SQL 2005 Express Edition to a system that already has an instance installed. Traditionally, you run Micrsoft's installer like I am in the command line below and it does the trick. Executing the command in my installer is not the issue, it's more a matter of dragging around the 40 MBs of MS-SQL installer that I don't need if they have SQL Express already installed. This is what my installer currently executes: SQLEXPR32.EXE /qb ADDLOCAL=ALL INSTANCENAME=<instancename> SECURITYMODE=SQL SAPWD=<password> SQLAUTOSTART=1 DISABLENETWORKPROTOCOLS=0 I don't need assistance with launching this command, rather the appropriate way to add a new instance of SQL 2005 Express without actually running the full installer again. I'd go into great detail about why I want to do this but I'd simply bore everyone. Suffice to say, having this ability to create a new instance without the time it takes to reinstall SQL Express etc. would greatly assist me for the deployment of my application and it's installer. If makes any difference to anyone, I'm using a combination of NSIS and Advanced Installer for this installation project.

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  • Message pump in .NET Windows service

    - by Pickles
    I have a Windows Service written in C# that handles all of our external hardware I/O for a kiosk application. One of our new devices is a USB device that comes with an API in a native DLL. I have a proper P/Invoke wrapper class created. However, this API must be initialized with an HWnd to a windows application because it uses the message pump to raise asynchronous events. Besides putting in a request to the hardware manufacturer to provide us with an API that does not depend on a Windows message pump, is there any way to manually instantiate a message pump in a new thread in my Windows Service that I can pass into this API? Do I actually have to create a full Application class, or is there a lower level .NET class that encapsulates a message pump?

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  • Ubuntu Server Cannot Route to the Internet

    - by ejes
    I've been having this problem for weeks now, and I can't seem to figure out the problem. My server can route the local network and serves it well, however it cannot access the internet. It can't be the router because everything else on this lan can route through the router. I've even switched the ethernet port. Any help would be appreciated. I've tried all the usual places, anyway, here are the configs: root@uhs:~# uname -a Linux uhs 3.0.0-16-generic-pae #28-Ubuntu SMP Fri Jan 27 19:24:01 UTC 2012 i686 i686 i386 GNU/Linux root@uhs:~# cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface # auto eth1 # iface eth1 inet dhcp auto eth0 iface eth0 inet static address 192.168.0.3 netmask 255.255.255.0 broadcast 192.168.0.255 gateway 192.168.0.1 root@uhs:~# ping -c 4 192.168.0.1 PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data. 64 bytes from 192.168.0.1: icmp_req=1 ttl=64 time=0.334 ms 64 bytes from 192.168.0.1: icmp_req=2 ttl=64 time=0.339 ms 64 bytes from 192.168.0.1: icmp_req=3 ttl=64 time=0.324 ms 64 bytes from 192.168.0.1: icmp_req=4 ttl=64 time=0.339 ms --- 192.168.0.1 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 2997ms rtt min/avg/max/mdev = 0.324/0.334/0.339/0.006 ms root@uhs:~# ping -c 4 209.85.145.103 PING 209.85.145.103 (209.85.145.103) 56(84) bytes of data. --- 209.85.145.103 ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3023ms root@uhs:~# ifconfig eth0 Link encap:Ethernet HWaddr 00:0c:6e:a0:92:6e inet addr:192.168.0.3 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::20c:6eff:fea0:926e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13131114 errors:0 dropped:0 overruns:0 frame:0 TX packets:10540297 errors:0 dropped:0 overruns:5 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3077922794 (3.0 GB) TX bytes:3827489734 (3.8 GB) Interrupt:10 Base address:0xa000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:7721 errors:0 dropped:0 overruns:0 frame:0 TX packets:7721 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:551950 (551.9 KB) TX bytes:551950 (551.9 KB) root@uhs:~# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.0.1 0.0.0.0 UG 100 0 0 eth0 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 root@uhs:~# # PRETEND Traceroute root@uhs:~# for i in {1..30}; do ping -t $i -c 1 209.85.145.103; done | grep "Time to live exceeded" root@uhs:~#

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  • Creating Service with Bluetooth activation in Android

    - by Mr. Kakakuwa Bird
    Hi I want to create a service in Android which will initially ask user if they want to start Bluetooth and set the Bluetooth discovery. My question is 1) Can I launch in the service following activities? if (!mBluetoothAdapter.isEnabled()) { Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBtIntent, 0); } // Set Phone Discoverable for 300 seconds. Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE); discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 600); startActivity(discoverableIntent); 2) I want to set discoverabilty of the phone on for lifetime of application. Is it possible? 3) I want to access empty space available on SD card. How should i do it? Thanks in advance.

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  • How can I extend this SQL query to find the k nearest neighbors?

    - by Smigs
    I have a database full of two-dimensional data - points on a map. Each record has a field of the geometry type. What I need to be able to do is pass a point to a stored procedure which returns the k nearest points (k would also be passed to the sproc, but that's easy). I've found a query at http://blogs.msdn.com/isaac/archive/2008/10/23/nearest-neighbors.aspx which gets the single nearest neighbour, but I can't figure how to extend it to find the k nearest neighbours. This is the current query - T is the table, g is the geometry field, @x is the point to search around, Numbers is a table with integers 1 to n: DECLARE @start FLOAT = 1000; WITH NearestPoints AS ( SELECT TOP(1) WITH TIES *, T.g.STDistance(@x) AS dist FROM Numbers JOIN T WITH(INDEX(spatial_index)) ON T.g.STDistance(@x) < @start*POWER(2,Numbers.n) ORDER BY n ) SELECT TOP(1) * FROM NearestPoints ORDER BY n, dist The inner query selects the nearest non-empty region and the outer query then selects the top result from that region; the outer query can easily be changed to (e.g.) SELECT TOP(20), but if the nearest region only contains one result, you're stuck with that. I figure I probably need to recursively search for the first region containing k records, but without using a table variable (which would cause maintenance problems as you have to create the table structure and it's liable to change - there're lots of fields), I can't see how.

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  • FACING ERROR WHILE CALLING AXIS2 WEB SERVICE ...

    - by darshanv
    Hello , I am new to axis ,I have created a web servcie with couple of methods using axis2 and deployed it on tomcat.And am calling that web service from my android program with the help of ksoap.But wen i call a method which doesn't take any parameter am gettin fine reply from web service which i can able to see on my screen,But wen i call anothr method which takes a string argument am getting namespace exception on server WEB SERVICE CODE IS ..... package Guru; public class DarshanSays { public String getMsg(String h) { return h+" ..the power of change is eVolution..."; } public String getEmpty(String d)throws Exception { return "empty string from tomcattttttttttt"; } } //AND program is String soap_action="http://Guru/getEmpty"; String method_nm="getEmpty"; String nmspc="http://Guru/"; String url7="//192.168.10.182:8080/axis2/services/Friday";//http: SoapObject request = new SoapObject(url7,method_nm); /*sending method parameters with SoapObject */ request.newInstance(); request.addProperty("h","darshan.....");//sending a parameter to a method SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); envelope.bodyOut=request; envelope.dotNet = true; envelope.encodingStyle = SoapSerializationEnvelope.XSD; Log.d("Step","3"); envelope.dotNet=true; /*setting outputsoap object sending request */ envelope.setOutputSoapObject(request); /*HttpTransportSE object creating sending it url */ androidHttpTransport = new HttpTransportSE(url7); //androidHttpTransport.setXmlVersionTag(""); Log.d("Step","4"); try{ androidHttpTransport.debug=true; androidHttpTransport.call(nmspc,envelope); } catch(Exception e) { Log.d("Transportcall",""+e); alert=new AlertDialog.Builder(this); alert.setMessage(""+e); alert.show(); } //exception is throw. Log.d("Step","5"); try { Log.d("giving...","resp"); SoapPrimitive sp=(SoapPrimitive)envelope.getResponse(); String hh=sp.toString(); Log.d("reply from web ser",".."+hh.toString()); //and erorr msg is SoapFault - faultcode:'soapenv:Server' faultstring: 'namespace mismatch require http://Guru found 192.168.10.182:8080/axis2/services/Friday' faultactor: 'null' detail: org.kxml2.kdom.Node@43d31390 ERROR IS coming only when am calling parameterized method. I am facing this issue only when am giving a call to parameterized method. Please Help.. thanks Darshan V

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  • Adding IoC Support to my WCF service hosted in a windows service (Autofac)

    - by user137348
    I'd like to setup my WCF services to use an IoC Container. There's an article in the Autofac wiki about WCF integration, but it's showing just an integration with a service hosted in IIS. But my services are hosted in a windows service. Here I got an advice to hook up the opening event http://groups.google.com/group/autofac/browse_thread/thread/23eb7ff07d8bfa03 I've followed the advice and this is what I got so far: private void RunService<T>() { var builder = new ContainerBuilder(); builder.Register(c => new DataAccessAdapter("1")).As<IDataAccessAdapter>(); ServiceHost serviceHost = new ServiceHost(typeof(T)); serviceHost.Opening += (sender, args) => serviceHost.Description.Behaviors.Add( new AutofacDependencyInjectionServiceBehavior(builder.Build(), typeof(T), ??? )); serviceHost.Open(); } The AutofacDependencyInjectionServiceBehavior has a ctor which takes 3 parameters. The third one is of type IComponentRegistration and I have no idea where can I get it from. Any ideas ? Thanks in advance.

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  • SQL Azure Roadmap gets a little clearer &ndash; announcements from Tech Ed

    - by Eric Nelson
    On Monday at Tech?Ed 2010 we announced new stuff (I like new stuff) that “showcases our continued commitment to deliver value, flexibility and control of data through data cloud services to our customers”. Ok, that does sound like marketing speak (and it is) but the good news is there is some meat behind it. We have some decent new features coming and we also have some clarity on when we will be able to get our hands on those features. SQL Azure Business Edition Extends to 50 GB – June 28th SQL Azure Business Edition database is now extending from 10GB to 50GB The new 50GB database size will be available worldwide starting June 28th SQL Azure Business Edition Subscription Offer – August 1st Starting August 1st, we will have a new discounted SQL Azure promotional offer (SQL Azure Development Accelerator Core) More information is available at http://www.microsoft.com/windowsazure/offers/. Public Preview of the Data Sync Service  - CTP now Data Sync Service for SQL Azure allows for more flexible control over data by deciding which data components should be distributed across multiple datacenters in different geographic locations, based on your internal policies and business needs.  Available as a community technology preview after registering at http://www.sqlazurelabs.com SQL Server Web Manager for SQL Azure - CTP this Summer SQL Server Web Manager (SSWM) is a lightweight and easy to use database management tool for SQL Azure databases, to be offered this summer. Access 10 Support for SQL Azure – available now Yey – at last! Microsoft Office 2010 will natively support data connectivity to SQL Azure – we can now start developing those “departmental apps” with the confidence of a highly available SQL store provisioned in seconds. NB: I don’t believe we will support any previous versions of Access talking to SQL Azure. The Pre-announced Spatial Data Support to Become Live – Live now* At MIX in March we announced spatial was coming and apparently it is now here - although I need to check. Related Links UK based? Sign up at http://ukazure.ning.com SQL Azure Team Blog http://blogs.msdn.com/b/sqlazure/

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  • Constructor Injection and when to use a Service Locator

    - by Simon
    I'm struggling to understand parts of StructureMap's usage. In particular, in the documentation a statement is made regarding a common anti-pattern, the use of StructureMap as a Service Locator only instead of constructor injection (code samples straight from Structuremap documentation): public ShippingScreenPresenter() { _service = ObjectFactory.GetInstance<IShippingService>(); _repository = ObjectFactory.GetInstance<IRepository>(); } instead of: public ShippingScreenPresenter(IShippingService service, IRepository repository) { _service = service; _repository = repository; } This is fine for a very short object graph, but when dealing with objects many levels deep, does this imply that you should pass down all the dependencies required by the deeper objects right from the top? Surely this breaks encapsulation and exposes too much information about the implementation of deeper objects. Let's say I'm using the Active Record pattern, so my record needs access to a data repository to be able to save and load itself. If this record is loaded inside an object, does that object call ObjectFactory.CreateInstance() and pass it into the active record's constructor? What if that object is inside another object. Does it take the IRepository in as its own parameter from further up? That would expose to the parent object the fact that we're access the data repository at this point, something the outer object probably shouldn't know. public class OuterClass { public OuterClass(IRepository repository) { // Why should I know that ThingThatNeedsRecord needs a repository? // that smells like exposed implementation to me, especially since // ThingThatNeedsRecord doesn't use the repo itself, but passes it // to the record. // Also where do I create repository? Have to instantiate it somewhere // up the chain of objects ThingThatNeedsRecord thing = new ThingThatNeedsRecord(repository); thing.GetAnswer("question"); } } public class ThingThatNeedsRecord { public ThingThatNeedsRecord(IRepository repository) { this.repository = repository; } public string GetAnswer(string someParam) { // create activeRecord(s) and process, returning some result // part of which contains: ActiveRecord record = new ActiveRecord(repository, key); } private IRepository repository; } public class ActiveRecord { public ActiveRecord(IRepository repository) { this.repository = repository; } public ActiveRecord(IRepository repository, int primaryKey); { this.repositry = repository; Load(primaryKey); } public void Save(); private void Load(int primaryKey) { this.primaryKey = primaryKey; // access the database via the repository and set someData } private IRepository repository; private int primaryKey; private string someData; } Any thoughts would be appreciated. Simon

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  • How to perform Linq select new with datetime in SQL 2008

    - by kd7iwp
    In our C# code I recently changed a line from inside a linq-to-sql select new query as follows: OrderDate = (p.OrderDate.HasValue ? p.OrderDate.Value.Year.ToString() + "-" + p.OrderDate.Value.Month.ToString() + "-" + p.OrderDate.Value.Day.ToString() : "") To: OrderDate = (p.OrderDate.HasValue ? p.OrderDate.Value.ToString("yyyy-mm-dd") : "") The change makes the line smaller and cleaner. It also works fine with our SQL 2008 database in our development environment. However, when the code deployed to our production environment which uses SQL 2005 I received an exception stating: Nullable Type must have a value. For further analysis I copied (p.OrderDate.HasValue ? p.OrderDate.Value.ToString("yyyy-mm-dd") : "") into a string (outside of a Linq statement) and had no problems at all, so it only causes an in issue inside my Linq. Is this problem just something to do with SQL 2005 using different date formats than from SQL 2008? Here's more of the Linq: dt = FilteredOrders.Where(x => x != null).Select(p => new { Order = p.OrderId, link = "/order/" + p.OrderId.ToString(), StudentId = (p.PersonId.HasValue ? p.PersonId.Value : 0), FirstName = p.IdentifierAccount.Person.FirstName, LastName = p.IdentifierAccount.Person.LastName, DeliverBy = p.DeliverBy, OrderDate = p.OrderDate.HasValue ? p.OrderDate.Value.Date.ToString("yyyy-mm-dd") : ""}).ToDataTable(); This is selecting from a List of Order objects. The FilteredOrders list is from another linq-to-sql query and I call .AsEnumerable on it before giving it to this particular select new query. Doing this in regular code works fine: if (o.OrderDate.HasValue) tempString += " " + o.OrderDate.Value.Date.ToString("yyyy-mm-dd");

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  • Important question about linq to SQL performance on high loaded web applications

    - by Alex
    I started working with linq to SQL several weeks ago. I got really tired of working with SQL server directly through the SQL queries (sqldatareader, sqlcommand and all this good stuff).  After hearing about linq to SQL and mvc I quickly moved all my projects to these technologies. I expected linq to SQL work slower but it suprisongly turned out to be pretty fast, primarily because I always forgot to close my connections when using datareaders. Now I don't have to worry about it. But there's one problem that really bothers me. There's one page that's requested thousands of times a day. The system gets data in the beginning, works with it and updates it. Primarily the updates are ++ @ -- (increase and decrease values). I used to do it like this UPDATE table SET value=value+1 WHERE ID=@I'd It worked with no problems obviously. But with linq to SQL the data is taken in the beginning, moved to the class, changed and then saved. Stats.registeredusers++; Db.submitchanges(); Let's say there were 100 000 users. Linq will say "let it be 100 001" instead of "let it be increased by 1". But if there value of users has already been increased (that happens in my site all the time) then linq will be like oops, this value is already 100 001. Whatever I'll throw an exception" You can change this behavior so that it won't throw an exception but it still will not set the value to 100 002. Like I said, it happened with me all the time. The stas value was increased twice a second on average. I simply had to rewrite this chunk of code with classic ado net. So my question is how can you solve the problem with linq

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