Option 1, Copy and Paste
This a very crude solution but I have used it before, admittedly with smaller volumes of data. Simply select the rows and columns in Excel, making sure they correlate with your database table schema. Copy to the Clipboard. Open up a connection to your database in Visual Studio select the last empty row and paste.
Like I said, a very crude solution but if it works and saves you time that's what matters. Try with a small selection of rows first and don't forget to exclude any auto-incrementing columns. If you convert to CSV first you will nuke any Excel formatting that may not import into your table schema. I have to be honest I don't know how this method will perform with larger datasets, obviously it will depend on the data in the Excel document, number of columns etc. You may need to move the data in chunks but it could well be quicker than other methods.
Option 2, CSV to DataTable
The second method requires some coding but will give you more control over how the data is mapped to the data table. It basically involves converting the document to a CSV from Excel, reading into a DataTable object looping the rows and inserting to the SQL Database table.
Dim dt As DataTable = New DataTable("myData")
Dim DataFile As FileInfo = New FileInfo("c:\myspreadsheet.csv")
Dim MyConnection As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" & DataFile.Directory.FullName & "';Extended Properties='text;HDR=NO';Jet OLEDB:Engine Type=96;")
Dim oledataAdapter As OleDbDataAdapter
oledataAdapter = New OleDbDataAdapter("SELECT * FROM [" & DataFile.Name & "]", MyConnection)
oledataAdapter.Fill(dt) 'Bind the csv to the data table
'LOOP AND INSERT HERE...
For Each DataRowObj As DataRow In dt.Rows
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