Treating data as text using Microsoft.ACE.OLEDB.12.0

Connection string

This Microsoft ACE OLEDB 12.0 connection string can be used for connections to Excel 2007, Excel 2010 and Excel 2013.

Use this one when you want to treat all data in the file as text, overriding Excels column type "General" to guess what type of data is in the column.

Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\myFolder\myExcel2007file.xlsx;
Extended Properties="Excel 12.0 Xml;HDR=YES;IMEX=1";

If you want to read the column headers into the result set (using HDR=NO even though there is a header) and the column data is numeric, use IMEX=1 to avoid crash.

To always use IMEX=1 is a safer way to retrieve data for mixed data columns. Consider the scenario that one Excel file might work fine cause that file's data causes the driver to guess one data type while another file, containing other data, causes the driver to guess another data type. This can cause your app to crash.