How can I display a null database column

ysfkay · December 4th, 2009, 07:08 AM

Is there anyway to retrieve a null column from the database and display it on a asp control without any modification,I tried this on a column with data type bit but it gives me errors, so I had to insert 'false' if value is null to the column before retrieving and displaying it successfully.

gbianchi · December 4th, 2009, 08:26 AM

well.. you have to tell the system what to display instead of null.. if you just want an empty string, you convert it and you solve the problem...

dparsons · December 4th, 2009, 09:57 AM

Without getting into a theoretical discussion on what null is or isn't, it is almost always best to handle this at your data store using functions such as ISNULL (MS Sql Server) or IFNULL (MySQL) to return some default data in the event of null.

hth.
-Doug

rstelma · December 4th, 2009, 12:21 PM

SELECT ISNULL([Bit Column], 1) FROM [Table]

I don't know about MySQL but in MS Sql Server you can supply a default value for the column so if for some reason you have not defined that value it will be false (0) by default.

What is your reason for wanting a NULL value in that column on the INSERT?

dparsons · December 4th, 2009, 12:28 PM

Yes, MySQL will allow you to specific default values for a given column.

IMHO what you are doing here (using NULL as a datatype) is bad practice. NULL is not a datatype and you shouldn't allow it to have any bearing on your application logic whatsoever.

hth.
-Doug