@Dushyant,

Have you created this assembly, compiled it? Is the file in this folder. Does your SQL have enough permissions to read this file?

Msg 6501, Level 16, State 7, Line 1
CREATE ASSEMBLY failed because it could not open the physical file “D:\1\SqlEmailDownloader\bin\Debug\SqlEmailDownloader.dll”: 3(failed to retrieve text for this error. Reason: 15105).
Msg 6528, Level 16, State 1, Procedure GetEmails, Line 2
Assembly ‘SqlEmailDownloaderAssembly’ was not found in the SQL catalog of database ‘HelloWorld’.
Msg 2812, Level 16, State 62, Line 2
Could not find stored procedure ‘GetEmail’.

@Jesil

You simply can not connect. You are using incorrect server address or/and port number or your server is down. This connection attempt failed article may help you.

Msg 6522, Level 16, State 1, Procedure GetEmails1, Line 0
A .NET Framework error occurred during execution of user-defined routine or aggregate “GetEmails1”:
Limilabs.Client.ServerException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 74.125.134.108:143 […]

@Mike

What error do you get? What is the exception message, stack trace?
Can you enable logging?

Imports System.Data
Imports Microsoft.SqlServer.Server
Imports Limilabs.Client.IMAP
Imports Limilabs.Mail
Public Class Class1
        <Microsoft.SqlServer.Server.SqlProcedure> _
        Public Shared Sub GetEmails()
            Dim record As New SqlDataRecord({ _
                New SqlMetaData("UID", SqlDbType.BigInt), _
                New SqlMetaData("Subject", SqlDbType.NVarChar, 128)})

            Using client As New Imap()
                client.ConnectSSL("Imap.gmail.com")
                client.Login("username", "password")
                client.SelectInbox()

                SqlContext.Pipe.SendResultsStart(record)
                For Each uid As Long In client.Search(Flag.Unseen)
                    Dim eml = client.PeekHeadersByUID(uid)
                    Dim email As IMail = New MailBuilder() _
                    .CreateFromEml(eml)

                    record.SetSqlInt64(0, uid)
                    record.SetSqlString(1, email.Subject)
                    SqlContext.Pipe.SendResultsRow(record)
                Next
                client.Close()
                SqlContext.Pipe.SendResultsEnd()
            End Using
        End Sub
    End Class

Here is the query

USE HelloWorld
GO
EXEC sp_configure 'clr enabled' , '1'

GO

RECONFIGURE

GO
Alter Database HelloWorld Set TrustWorthy On

GO
CREATE ASSEMBLY [System.Windows.Forms] FROM 'C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Windows.Forms.dll'
With Permission_Set=Unsafe

GO

CREATE ASSEMBLY SqlEmailDownloaderAssembly FROM 'E:\mail\SqlEmailDownloader.dll'

With Permission_Set=Unsafe

GO

CREATE PROCEDURE GetEmails

AS EXTERNAL NAME SqlEmailDownloaderAssembly.Class1.GetEmails

GO

Thanks
Mike

@Bill

In our practice the most important thing is to save the original, raw eml data for later reference.

True it takes space, but if you have raw data, at any point of time,
you can check S/MIME digital signatures, DKIM signatures, and
if you forgot to include some important detail in your DB structure,
you are able to recreate it from original data.

As for the DB structure we can’t give you any good advice,
as it greatly depends on what are you planning to do with the data:
Searching? Are attachments important? Do attachments need to be searchable?
Are there any headers that are specially important to you?