Issue importing data from MS Access into SQL Server

Question

I have a bunch of Yes/No fields in Access database that I need to get into SQL Server. If I look at the Access data, those fields contain either 0 or -1. On SQL Server side I created fields of type BIT which did not work for me, I am assuming because BIT expects 0 or 1. Here is my error:

The given value of type String from the data source cannot be converted to type bit of the specified target column. ---> 
System.FormatException: Failed to convert parameter value from a String to a Boolean. 
String was not recognized as a valid Boolean

I also tried using nvarchar(3) which also did not work, saying "The given value of type String from the data source cannot be converted to type nvarchar"

Which data type should I use? I have tried BIT, TINYINT, NVARCHAR(3), CHAR(1), and CHAR(2).

Using CHAR(1) or CHAR(2) gives me a different error:

System.Data.SqlClient.SqlException (0x80131904): Received an invalid column length from the bcp client for colid 13.

But either way nothing works

Answer 1

I always use SMALLINT (2-byte signed integer) to allow for 0 and -1, and avoid the hassle with BIT fields.

https://msdn.microsoft.com/en-us/library/ms187745.aspx

Answer 2

Use a bit, and you'll want to do a transform from Yes to 1 and No to 0 during the import, you can use a CASE statement to handle this operation.

IE

CASE WHEN colVal = 'Yes' THEN 1 ELSE 0