Is It Bad Practice To Leave A SqlCeConnection Open Through The Duration Of A Mobile Application?
Jan 24, 2008
I know that with traditional SQL systems, it is important to only open connections to a sql server when they are needed. However, since there is no "server" in mobile apps, is it bad practice to leave one open throughout the duration of an application?
The application is going to be constantly reading and writing to the data tables and it seems like it might be a good idea to leave it open.
Thanks!
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Apr 15, 2008
Good day,
I am writing an application using VB.Net 2005 for the Windows CE 5.0 device and it is connecting to a SQL Server 2005 Mobile Edition Database.
The trouble I'm having is establishing a connection to a SQL Server Mobile database on the device.
Here is the code I am using:
Code Snippet
Public gConnectionString As String = "Data Source=Program FilesMobAppMobDB.sdf;Persist Security Info=False;"
Code Snippet
Imports System.Data.SqlServerCe
Public Class DBManager
Public Shared gSQLCEConnection As SqlCeConnection
Public Shared Function OpenDB() As Boolean
If gSQLCEConnection IsNot Nothing Then
Throw New InvalidOperationException("Connection already open.")
End If
gSQLCEConnection = New SqlCeConnection(gConnectionString)
Try
gSQLCEConnection.Open() 'Error occurs here
Return True
Catch ex As SqlCeException
MsgBox(ex.Message & vbCrLf & ex.HResult & vbCrLf & ex.NativeError & vbCrLf & ex.Source)
Return False
End Try
End Function
In the immediate window I recieve the following messages:
A first chance exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll
A first chance exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll
A first chance exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll
A first chance exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll
A first chance exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll
A first chance exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll
A first chance exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll
A first chance exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll
A first chance exception of type 'System.Data.SqlServerCe.SqlCeException' occurred in System.Data.SqlServerCe.dll
I believe that the first few lines are caused by the icons/pictures that I have included with my app, but the SqlCeException line occurs when the connection to the .SDF file is trying to be established.
Here is the exception output:
Message: "" (Blank)
HResult: -2147024882
NativeError: 0
Source: SQL Server 2005 Mobile Edition ADO.NET Data Provider
Programs under Remove Programs on the PDA are:
Microsoft .NET CF 2.0 ENU-String R...
Microsoft .NET Compact Framework...
Microsoft SQL Client
Microsoft SQL Mobile 2005
Microsoft SQL Mobile 2005 [EN]
Microsoft SQL Server 2005 Compact...
Microsoft SQL Server 2005 Compact...
Microsoft SQL Server 2005 Compact...
Microsoft SQLCE 2.0
Microsoft SQLCE 2.0 Dev
Any ideas on what could be stopping this connection from being established? It was working before but all of a sudden just stopped. I have warm booted, cold booted, and rebuilt with no luck and also checked that SQL Query Analyzer is not running on the PDA and that the connection string is valid.
The call to OpenDB occurs in the form_load of the startup object.
Thanks in advance,
Leon
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Jun 7, 2006
Hi there,
I got an approach like that:
1) Read something from DB - check the value, if true stop if false go on2) Read the second Value (another SQL Statement) - check the value etc.
Now I could open the connection at 1) and if I have to go to 2) I leave the connection open and use the same connection at 2). Is it ok to do that?
The other scenario would be opening a connection at 1), immediately close it after I read the value and open a new connection at 2).
Thanks for the input!
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Mar 20, 2008
Hello, I have always closed my db connections asap after opening them and have always thought this was the best practice. But now I am wondering if I can just leave the connection open.
I created a windows service which runs on a timer and executes every 5 seconds. The problem is that the code takes longer than that to process and the code may be executing three times at once. Im worried that since I use the same connection each time the code executes that a connection opened by the first run through may be closed or reopened by the second or third running of the code resulting in an error. The connection is opened and closed about 10 times each time the timer event fires. Should I open the connection once and leave it open when the service is started and close it when it is stopped or on any error?
Thanks
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Feb 3, 2005
I am used to writing applications that hit the database "every so often" and am happy with opening and closing the connection to SQL Server for each one.
I am now writing an application that monitors a table where rows are written to it by a 3rd party application at possibly several rows per second. My job is to "pickup" those rows, analyse the data and move them to different tables. This will be done with a timer which is currently set to tick every second.
My question is: At what stage should I start to think about keeping open a permanent connection to the database ?
1 row per second ?
100 rows per second ?
Any suggestions appreciated.
Steve.
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Feb 16, 2006
What is exactly the recommended way of using a SqlCeConnection object in your application?
In all the examples I see (IBuySpyDelivery for example) it opens the connection object in the constructor and leaves it open most of the time until the class gets disposed.
Is that the way to do it? Or should you open and close the connection for each database action (insert/select/delete) you're doing on the local SQL Mobile database?
I'm a bit confused, but maybe I'm messing up the way of working on remote database servers with how it should be done on a local SQL Mobile db.
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Aug 9, 2006
Help!
I am trying to implement a web service that creates and populates a SQL Mobile database file, then returns the created database to a mobile device as a byte array. The database size could be in excess of 500,000 rows, which is why I want to do as much of this preprocessing on the server before it gets to the mobile device. I can't use replication since I have to do some shaping of the data before I can use it on the mobile device.
Unfortunately, the web service is throwing the following exception when I try to instantiate a SqlCeConnection object:
"System.NotSupportedException: SQL Server Everywhere Edition is not intended for ASP.NET development."
Are there any suggestions as to how I can get around this potential limitation? If I refactor out the code that actually performs the SqlCe operations to a separate assembly, but still call that assembly from within the ASP.NET process, will I get the same error?
I know that you can work with Sql Mobile databases from the deskop, and I suppose I could invoke a console application to create the database, but that seems like such a hack.
Thanks for any advice,
Matthew
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Dec 4, 2007
I'm having a problem where I am getting a "Permission denied" exception when I call Open on a SqlCeConnection object using SqlCE version 3.5. It does this when mode is set to Read Only in the connection string. Furthermore it does this on XP, but not Vista. Here is the connection string I'm building:
string connectionString = "Data Source='" + fileName + "';password=" + DBPassword + ";mode='Read Only';Temp File Directory='" + Path.GetTempPath() + "'";
A prompt response with a resolution to this would be greatly appreciated.
Ron
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Jul 11, 2006
Hi,
I'm having the problem that my application hangs on SqlCeConnection.Dispose() when I'm closing the app.
public class DatabaseManager : IDisposable
{
private DbConnection connection = null;
// Singleton
private DatabaseManager()
{
this.CreateConnection();
}
~DatabaseManager()
{
this.Dispose();
}
public void Dispose()
{
if (this.connection != null)
{
this.connection.Dispose();
}
}
// ...
}
This only happens when I'm calling Application.Exit(); and Dispose is called through the destructor of the DatabaseManager class. When I'm disposing the connection during normal work the call works as intended. BTW I'm using SQL Server Mobile 3.0.5214.0 on a PPC 2003 AKU2 (Symbol PPT8846 industrial device).
Thanks for support,
Klaus
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Mar 23, 2006
Hello,
I am developping a non-managed C++ application for PocketPC using a SQL Server mobile database.
The application is compiled for PocketPC 2003 and uses SQL Server Mobile v2. I use Visual Studio 2005. But I need to compile the application for Windows Mobile 5.0 devices. So I installed the WM5 SDK and had the WM5 into my project configuration.
The "ssceoledb.h" which I include incluses the "transact.h" file. But my problem is that this file is only provided with the PocketPC 2003 SDK and not in the WM5 SDK.
So I cannot use the WM5 configuration project with SQL Server. I also tried with the last SQL Server Mobile 2005 (ie v3.0) and the "ssceoledb30.h" also includes "transact.h".
Did I miss something to install ?
Do you know how I can resolve the problem ?
By advance, thank you for any answer.
--
Gregoire
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Jul 21, 2006
This is a great tutorial and it's a shame one of the more important steps was missed.
In the €œCreate the snapshot user€? section you you find the steps to create the snapshot_agent account. Then in the €œCreate the snapshot folder€? section you find the share and folder permissions. However, at no point do the instructions advise you about adding the snapshot_agent to the SQL Server Logins. The result is that agent cannot perform the initial snapshot but you won't find this out until 50 steps later after Step 10 in the section €œCreate a new subscription".
To get back on track, openthe Object Explorer's Security section and add the snapshot_agent to your logins. Then using the "User Mappings", set an appropriate level for the SQLMobile database role. Once completed you then need to run the agent.
Right-click the SQLMobile publication you created and select "View Snapshot Agent status". From that dialog you can select "Start" to run the agent. When it completes, you can return to the tutorial section "Create a new subscription" and continue with the tutorial.
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Nov 3, 2007
I am studying the tutorial in SQL Server 2005 Mobile Edition Books Online, and the topic is Creating a Mobile Application with SQL Server Mobile. I have got a problem when creating a new subscription after created a new SQL Server Mobile database. And the problem is shown below:
New Subscription Wizard
- Beginning Synchronization (Success)
- Synchronizing Data (100%) (Error)
Messages
* Failure to connect to SQL Server with provided connection information. SQL Server does not exist, access is denied because the IIS user is not a valid user on the SQL Server, or the password is incorrect.
HRESULT 0x80004005 (29061)
* 無法完æˆ?作æ¥ã€‚
- Finalizing Synchronization (Stopped)
- Saving Subscription Properties (Stopped)
Before I have met this problem, I have finished all the task. And I can browse the localhost web site by using anonymous account even I use internet explorer or browse the directly in IIS.
Does anyone can solve it?? Thank you very much~~~
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Feb 20, 2007
Hello Reporting Services Gurus!
I'm about to start on my first reporting services project, but before I mess it up, I'm looking for some guidance on how best to achieve my mission. Here's what I'm looking to achieve:
I have a datacentric application (SQL Server 2005 Express w/ Advanced Services backend) in which I want to build about 50 "canned" reports for the end users. I want to build the reports utilizing server mode so I can take advantage of some of Reporting Services advanced features. I'm not sure what the best practice would be to build the reporting services project. Is it better to include the report project as another project within the application solution? Or, should I build the report project independent of the application solution? What are the pros and cons of doing it either way? How does including the report project build if it's included in the application solution? How would a ClickOnce deployment deploy the report project to the report server?
My ultimate goal would be to have an "off-the-shelf" software solution that includes an installation package consisting of the application project and report project. Is it even possible due to the Reporting Services architecture to achieve an install in this manner with ClickOnce, Windows Installer, or Installshield? Or, is building the report project indepedent of the application project and deploying the reports to the report server "manually" (i.e. deploy within the report server project) the only solution?
Any help would be greatly appreciated!
Tony
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Jan 22, 2008
I am geeting following error while trying to acquire db connection. I use sql server ce2.0 with vs2005
Failed to find or load the registered .Net Framework Data Provider
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Jun 4, 2015
I have the following SQL query
SELECT
[Req_ID]
,[Service_Name]
,[Req_Started_Date]
,[Task_Name]
,[Task_Status]
,[Performer_Full_Name]
[code]....
Which works fine, but what I need to calculate the total duration of a request based on the duration of the tasks completed in the request based on Req_ID. I would like to use the CASE statement I have to determine the SLA_Mins for each task and add them together to get total request SLA_Mins.
Below is the create table schema and data
GO
/****** Object: Table [dbo].[MidrangeOtherSourceControl] Script Date: 06/03/2015 18:13:15 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[MidrangeOtherSourceControl](
[Req_ID] [float] NULL,
[Service_Name] [nvarchar](255) NULL,
[code]....
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Jan 30, 2006
Hi
My application :
On PC : Access application + Access DB
On PocketPC : Embedded Visual Basic 3.0 application + PocketAccess DB
I synchronise my DBs through ActivSync.
It runs good before Windows Mobile 5.
My customers asked me for new PocketPC with this application, so I bought some new PocketPCs : but as I see, syncronisation with Access is no more supported.
So what are my solutions ?
My customer wait for there PocketPC, so I need a quick solution, I don't want to rewrite all my application now.
My application run before WM5, so now I don't want to have to pay for a Visual Studio .Net, some SQL Server, etc ....
Please, what are the solutions that won't cost me more than the time that have already lost with this new Windows Mobile 5 ?
Joël
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Feb 14, 2006
Hi,
I've found guides on creating a mobile application but everything is on 1 computer.
What i'd like to do is to seperate into 3 parts for added security.
One is used to store the Database.
One is used as an IIS Server (Web Server).
One is used as a Deployment Server.
Is there a step-by-step guide to this setup?
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May 9, 2007
Hi
guys.
Is it possible to interoperate between SQL mobile and applications developed in j2me?
I need my application in j2me to perorm the basic database operations in sql mobile db.
Please advise
Thanks
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Apr 3, 2008
I am creating a mobile application in which i am implementing data synchronization through merge replication method as per the step by step procedure given in the following link:-
http://msdn2.microsoft.com/en-us/library/ms171908.aspx
I am using SQL server Mobile Edition which is included in SQL server 2005 in this application, but the application suggests to use SQL server Compact Edition. I was able to successfully create the publication, but not able to run the sqlcesa30.dll file of the created virtual directory in the internet explorer. Is this problem because of i'm not using SQL server Compact Edition? and also let me know if i use SQL server Mobile Edition, do i need to install its Server Tools? If yes, please give me the link to download the tools needed.
Reply Soon.
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Feb 11, 2006
Dear All,
I am trying to build a simple mobile application. I am very new to this. Thus I am trying to access the build in database in the folder C:Program FilesMicrosoft SQL Server 2005 Mobile EditionDeviceMobilev3.0Northwind.sdf. I am following the steps in the wizard to help me. When I press test connection is say Test Connection Succeeded. But when I press the ok button I get this error as "Unable to find the requested .Net Framework Data Provider. It may not be installed". I am running VS 2005. Can anyone pls help ?
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Mar 12, 2008
Hi there, i am building a mobile app using vs 2008, the app has about 8 - 12 forms that collect data.. i am thinking of
i am trying to decide how i want to save the temporary work data while the user fills the data collection forms.
when the user selects to create a new report, i will
create a new xml file...
as user moves from form to form, i will update the file
when the user has finished filling up all the data i will create a transaction and insert the data into the sql ce database and delete the file...
i will be using sql ce 3.5
i think it supports transactions
i think it also supports identity.... i am using sql management studio 2005 standalone , so i cannot visually modify the 3.5 sdf.,..,. is there a tool for 2008 that will let me visually modify the table(s)? i dont want to use the 2008 feb community edition...
is there a better way to do this? should i skip the xml and go directly into sql ce insert (for the first record creation) and updates? i think this will be a performance killer on a win mob devilce (5.0)
p.s. i cannot store data in a class, and then commit the class to the transaction because if the application crashes i will loose class data, so xml file will be needed.,
suggestions?
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Jan 21, 2008
Hi,
I'm writing a windows application using VB.NET 2005 that must connect to Pocket PC via ActiveSync to read data from SQL Server CE. This is my code:
Dim cnn As New SqlCeConnection
cnn.ConnectionString = "Data Source =Mobile DeviceStorage CardProgram FilesMyAppMobileDB1.sdf"
cnn.Open()
But I get the following error:
The path is not valid. Check the directory for the database. [ Path = Mobile DeviceStorage CardProgram FilesMyAppMobileDB1.sdf ]
Any help would be greatly appreciated!
Leila
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Feb 5, 2006
I've read that microsoft.applicationblocks.data for .net v2 can't be deployed to a mobile app, and my experience bears that out. So I 'm wondering if there are application blocks for windows mobile 5 that would know how to both talk to sql server mobile and sql server 2005. I see OpenNetCF has a port but as far as I can tell, they only address sql server mobile and not talking to a sql server 2005 remote database. I can use the OpenNetCF version for my sql server mobile requirements, but I'm hoping there is an encapsulation of sqlclient calls for communication with my server db.
thanks
braden
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Feb 28, 2008
Hi There,
I would like to know what the recommended Number of Sql Mobile Databases Per Application?
I appreciate any response!
Thanks!
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Jun 28, 2007
Hello!!
I completed that example that I pasted in the subject part and when I try to synchronize my mobile database, the data from the server appear in my pocket pc; but when i refresh the data on my pocket pc they do not show on the server.
Can anyone give me a hand?
thanks
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Jul 24, 2006
Event ID - 1001 and Event ID - 1004.
Source - MsiInstaller
Error Description for Event ID - 1001:
Detection of product '{8670F53C-8AD7-4F34-BDBA-17B38A18CB65}', feature 'SQL_SSMSEE' failed during request for component '{6EC5DFBD-F6B5-4F02-8432-BFB8B03562B8}'
Error Description for Event ID - 1004:
Detection of product '{8670F53C-8AD7-4F34-BDBA-17B38A18CB65}', feature 'SQL_SSMSEE', component '{180F515D-F56C-40DD-9D71-CC532EA8E286}' failed. The resource '' does not exist.
While opening our SAP Mobile Client Application, in the task manager MSIEXEC.EXE is running and trying to repair the application and this will cause our application to take time to lauch. In the Event viewer, whenever we try to lauch our application we are getting this event id's. Can you please kindly provide a solution for this msg.
Regards,
Thiyagarajan.R
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Feb 2, 2006
I am working with merge replication. The db server is running Windows 2003 Server Std x64 with SQL 2005 Std x64. The IIS server is running Windows 2003 Server Stx x86. The clients are Windows Mobile 5.0 running SQL 2005 Mobile.
I have previously been able to get the test client to initialize a subscription to the publication. I made some changes recently and added about 7 tables, bringing the total articles to 104. Some of the articles have unpublished columns, which means they are using vertical filtering as well. This publication is also using parameterized filters. During publication creation, there are several warnings that "Warning: column 'rowguid' already exists in the vertical partition".
The snapshot agent runs without any errors. When the client attempts to initialize, I get the error "The buffer pool is too small or there are too many open cursors."
My question is 2 part. First, what is causing this error, and second, how can it be resolved?
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Jan 31, 2008
Hello
I am writing a Desktop application accessing a SSCE database. I am running Windows XP SP2, VS2005 SP1, and have SQLServerCE3.1 installed. Debugging the application shows that ds.m_spInit->QueryInterface() returns E_NOINTERFACE. I have checked that SSCE runtime library is installed, IDBCreateSession uuid exists in the registry and m_spInit.CoCreateInstance(CLSID_SQLSERVERCE_3_0) return S_OK. Can you suggest me what need adding/installing to get the CSession.Open(datasource) working?
Thanks
Ares,
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Oct 22, 2007
How do i know whether the connection is open with the sqlserver database while work in the application?
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Jan 24, 2008
Hi guys..
i'm having a hard time to do this one..
you see these are the requirements..
1. there is a text file named "Loan"
2. i must create a program using ASP.net wherein the text file can be imported in the system.
3. after importing, i must save the whole text file in a database.
my questions are:
1. what code can i do to open up a text file?
2. how can i save the text file into a database?
3. is there any way that i could import the file and view its content in my application?
4. after viewing, how can i save the text file as a text file in a database?
thanks to the help
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Oct 31, 2006
I was wondering if there was a way to set a default project to open in Microsoft SQL Server 2005 when the application launches.
Perhaps there's a certain registry key I could edit?
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Apr 14, 2008
Long story short -
Have two C# applications - one WinForms desktop app, the other a WinForms smart device app. Both use SQL Server Compact CE 3.5 to store data locally. Both work just fine.
Now the desktop app needs to open and update the .SDF file that is stored on the Windows Mobile device. (Device will be docked via USB.)
What format would the path to the .SDF look like that the WinForms application would need to specify in order to open it?
Thanks for reading.
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Feb 26, 2008
I'm attempting to use RDA to synchronize a pocket pc emulator with SQL Server 2005 database by following tutorial http://msdn2.microsoft.com/en-us/library/aa454892.aspx, which uses AdvWorksMobile database that comes with SQL Server 2005.
When get to testing of "To test application features " ( step 4 of the merge replication setup lab ), I am receiving SQLCe Exception errors.
ORIGINALLY, I was able to deploy an application and view the local database on the emulator, but once I clicked "InitSinc" button, I received an error.
"Failure to connect to SQL Server with provided connection information. SQL Server does not" exist, access is denied because the SQL user is not a valid user on the SQL Server, or the password is incorrect.
Found this error listed in Server Agent Errors log http://technet.microsoft.com/en-us/library/ms172357.aspx, but it wasn't very helpful since it doesn't provide any suggestions on fixing the problems.
I am brand new to SQL CE Server , mobile programming and .NET framework in general so please bare with me
All the connections / security settings, etc that were set up were taken from a tutorial so I am not sure what SQLCeServer is complaining about. Reading up on the error on the web didn't help, it all pointed to making sure that the snapshot folder had correct permissions set up. I verified that MACHINENAMEUISR_MACHINENAME guest user had Read rights to the database so I don't think that piece is the problem. Otherwise ,Merge publication has been setup in Microsoft SQL Server Management Studio by following the tutorial.
I am trying to run this sync on my home pc so there should be no issues with any user permissions
I have IIS installed
I did NOT have SQL Server Agent running in management studio at this time
I am trying to run this tutorial on an XP machine, which is my regular home PC so I dont think there are any special networking settings to consider
I am able to hit http://localhost/AdvWorksMobile/sqlcesa30.dll from my pc OK, but when I try to hit it from a cradled emulator ( after replacing "localhost" with "MACHINE_NAME" ), Internet Explorer on the emulator gives me a "Cannot Connect With Current Settings" error message. This part wasn't part of tutorial but decided so not sure if I am supposed to be able to hit it from my emulator..so I am not sure if the fact that I can't hit it is related to the problem.
AFTER STARTING SQL SERVER AGENTin Microsoft SQL Server Management Studio, I killed the application, and after relaunching it, it hits "The Specified table does not exist [Vendor]" error. This time it doesn't even launch first - that is I dont even get to pressing "InitSinc" button. Debugger is showing that this error is hit on the following line in AdvWorksMobile.AddWorksDataSetTableAdapters
int returnValue = this.Adapter.Fill(dataTable);
I am not sure why the errors changed on me after starting SQL Server Agent.
What can I do to fix this connection problem?
Thank you so much for your help!
Irina
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