Unhandled Exception When Launching Application - Attach Database Failed

Unhandled Exception When Launching Application - Attach Database Failed

• binod m paul

  This error is happening from the compiled app - the app was built, a setup was produced, and it was installed on a machine without Visual Studio installed. Unfortunately, I cannot supply a code example, as the app runs OK from the IDE on the machine where it was built. You suggested to make sure the database is in the same path as the app directory. When the app was installed, there were no options to specify where any components were to be installed - the setup took care (or failed to take care) of that. How am I able to control the DB being installed to the same location as the app This would need to be done by the setup - we will have clients installing this app themselves from the setup, so I would not have the ability to manually move files around.
  

• Sam4u2e

  I have been working in at least 3 (three) different environments (more actually) - and in each case, the connection string variations were, to say the least - at first, cryptic.

  Now, before I go on, I'd like to say that notwithstanding the increased complexities associated with establishing a valid database connection string - the additional params are - in a bummer sense - appreciated..... because, it appears that the flexiblity they provide overrides ones frustration while attempting to figure out -What's going on!

  I too have experienced a similar issue and - ok, maybe it's old school, but I needed a much more dynamic method to deal with these connection string issues when on site vs. in dev environment... and decided that i would create a .ini file to contain the connection string params and thus allow for the dynamic 'throwing of switches' that would allow a proper connection and 'depending on the given environment'.

  Let's consider at the very least 3 environments

  1) VS2005 with SQL Server Express (advanced or not)
  2) VS2005 with SQL Server 2005 AND SQL Server Express (advanced ed)
  3) VS2005 hitting a remote server having SQL Server Standard or higher

  Oh, and what about this one;

  We develop (for SQL Express) against H:\VBProjects\CustomerApp and when we execute in the development env, the database is copied to the H:\VBProjects\CustomerApp\bin\debug directory and we think all is fine.

  But when we install the app on the clients laptop, the mdf and ldf file need to go to say, c:\data directory

  Is it any wonder the connection string doesn't work It shouldn't be... but one is simply - at first - caught off guard. Simple as that, and no matter how experienced you are - or not - it always seems to happen to one degree or another. That's programming.

  There are more scenarios, but this is a good example of the number of configurations one might encounter.

  For example, you may develop against a local instance and deploy to a remote server instance.

  In order to be able to 'debug on the fly' (hey, this stuff is tricky) at the client site, we created an ini file (like I said, old school - but useful) as shown below;

  '*********************************************************************************

  [DATABASE SETTINGS]
  USES_SQL_SERVER_EXPRESS=True
  USES_SQL_SERVER_2005=False

  SERVER_NAME=(local)
  INITIAL_CATALOG=TESTHARNESS
  NAME_OF_DATABASE_FILE=TESTHARNESS.MDF
  LOCATION_OF_DATABASE_FILE=C:\DATA
  SQL_AUTHENTICATION=False
  UID=sa
  PWD=
  Integrated_Security=True
  User_Instance=True

  '*********************************************************************************

  You will notice that the UID & PWD are there, and one would have a number of options with that;

  1) Realize your debugging and before the build want to know all params associated with a gold code build prior to deploying to the client... so these come out later, but for now - you're simply want it to work at the client site in order to determine exactly what those params need to be.

  They may be one thing on the employees laptop using a SQL Server Express mdf (remoting), but another connection string may be used on a desktop that always hits the server.

  Create an INI file and place it in app.path

  2) Locate a INI file reader class or write your own. (See resources below)

  3) Actually, mdsn had it all the time, the keywords used to zero in were simply wrong at first, but persistance paid off. Anyway, theres a function on msdn which you can search for - but - we modified it to read the variables from the .INI file as appears below;

  It's not as elegant as it could be, but - it does the job of allowing one to get connectivity going rather quickly.

  Create a module or use an existing one and create a string variable called: Application_Connection_String

  '*********************************************************************************

  Private Function BuildConnectionString() As Boolean

  Dim cIniFiles As New INIFile

  Dim sServerName As String = INIFile.GetValue("DATABASE SETTINGS", "SERVER_NAME", "Persist.dat")

  Dim sDBFilePath As String = INIFile.GetValue("DATABASE SETTINGS", "LOCATION_OF_DATABASE_FILE", "Persist.dat")

  Dim sDBFileName As String = INIFile.GetValue("DATABASE SETTINGS", "NAME_OF_DATABASE_FILE", "Persist.dat")

  Dim bUsesSQLExpress As Boolean = INIFile.GetValue("DATABASE SETTINGS", "USES_SQL_SERVER_EXPRESS", "Persist.dat")

  Dim bUsesSQLAuthentication As Boolean = INIFile.GetValue("DATABASE SETTINGS", "SQL_AUTHENTICATION", "Persist.dat")

  Dim strInitialCatalog As String = INIFile.GetValue("DATABASE SETTINGS", "INITIAL_CATALOG", "Persist.dat")

  Dim sIntegratedSecurity As String = INIFile.GetValue("DATABASE SETTINGS", "User_Instance", "Persist.dat")

  Dim sUserID As String = INIFile.GetValue("DATABASE SETTINGS", "UID", "Persist.dat")

  Dim sUserPwd As String = INIFile.GetValue("DATABASE SETTINGS", "User_Instance", "Persist.dat")

  Dim sUserInstance As String = INIFile.GetValue("DATABASE SETTINGS", "User_Instance", "Persist.dat")

  Dim strConnectionString As String = ""

  BuildConnectionString = False

  If bUsesSQLExpress Then

  Try

  Dim connectString As String = ""

  If bUsesSQLExpress Then

  connectString = "Server=" & sServerName & "\sqlexpress;Integrated Security=" & sIntegratedSecurity & ""

  Else

  connectString = "Server=" & sServerName & ";" & "Integrated Security=" & sIntegratedSecurity & ";Connect Timeout=10;User Instance=" & sUserInstance

  End If

  Dim builder As New SqlClient.SqlConnectionStringBuilder(connectString)

  builder.AttachDBFilename = sDBFilePath & "\" & sDBFileName

  strConnectionString = builder.ConnectionString

  Using connection As New SqlClient.SqlConnection(builder.ConnectionString)

  connection.Open()

  BuildConnectionString = True

  End Using

  Catch ex As Exception

  MsgBox(ex.Message, MsgBoxStyle.Critical, "Error In BuildConnectionString")

  Dim EL As New ErrorLogger

  EL.WriteToErrorLog(ex.Message, EventLogEntryType.Error, "Test Harness - modAcessLayer")

  End Try

  End If

  If Not bUsesSQLExpress Then

  Try

  Dim connectString As String = ""

  If bUsesSQLAuthentication Then

  connectString = "Data Source=" & sServerName & ";Initial Catalog=" & strInitialCatalog & ";User ID=" & sUserID & ";password=" & sUserPwd & ""

  ElseIf Not bUsesSQLAuthentication Then

  connectString = "Data Source=" & sServerName & ";Initial Catalog=" & strInitialCatalog & ";Integrated Security=True"

  End If

  Dim builder As New SqlClient.SqlConnectionStringBuilder(connectString)

  strConnectionString = builder.ConnectionString

  Using connection As New SqlClient.SqlConnection(builder.ConnectionString)

  connection.Open()

  BuildConnectionString = True

  End Using

  Catch ex As Exception

  MsgBox(ex.Message, MsgBoxStyle.Critical, "Error In BuildConnectionString")

  End Try

  End If

  Application_Connection_String = strConnectionString

  End Function

  '*********************************************************************************

  My intention was not to create an entire article, rather to point you in a direction.

  Your next steps would be to call the function via a button and step through it, ensuring that it populates the global Application_Connection_String variable and, of course connects successfully.

  Then, perhaps you'd create a resource (My.Resources.ConnectionString) and populate that resourse with the connection string at application startup.

  You might embed this within the app - or one could perhaps leave it in the .INI file - and encrypt it or whatever.

  I hope this helps.

  Resources;

  www.codeproject.com --> search on ini <space bar> files

  
  

• omar_rapid

  some code would be helpful where the error is occuring in. Also make sure the database is in the same path as the application directory but also the same path specified in code
  
  

• Thara Riaz

  well can you post the connection string of the database Make sure that the computer does also have SQL Server installed (it should be otherwise you would get a Server does not exist or access denied error instead)

  From the exception this is the problem:

  An attempt to attach an auto-named database for file C:\Documents and Settings\Erik\Local Settings\Apps\2.0\Data\34CATLWM.YEH\RYD4M9PO.CE3\newd..tion_7ef9fb2004316736_0001.0000_18ae9c26aea5f895\Data\DueDiligence.mdf failed

   

  most likely a problem with the database path. Would be ideal if you can post the connection string of the database

  
  
  
• Unhandled Exception When Launching Application - Attach Database Failed