Store "Null" to Date/Time datatype in Access

[calvin]

I want to update a Date/Time datatype in MS Access by Null value(or blank?). A variable is declare as DateTime datatype in ASP.NET. I was use the following approach try to set null/empty.

 

Dim TimeIn as DateTime

TimeIn = New DateTime <<------ What should i change here?? :confused:

 

'Update Statement here'

...

...

cmdUpdate.Parameters.Add("@TimeIn", TimeIn)

...

 

 

After update the DB, all the column which store TimeIn contain a value 01-01-2001, this is not what i want. I want it is "Totally nothing(null/empty)" in the column. When I bind the TimeIn to the datagrid, it will show "12:00:00 AM "

 

Is anyone know to solve it.Thank you

 

Calvin

[Joe Mamma]

TimeIn = New DateTime <<------ What should i change here??

try

 

TimeIn = null

[Derek Stone]

Value types can't be null. You need to do something like this:

 

Dim birthdate As DateTime = DateTime.MaxValue

If birthdate = DateTime.MaxValue Then
    cmdUpdate.Parameters.Add("@TimeIn", Nothing)
End If

 

Then again I don't recommend allowing null values into your database, but that's a whole 'nother bag of beans.

[calvin]

I get this error:

 

Parameter 0: '@TimeIn', the property DbType is uninitialized: OleDbType.Empty.

 

I think we can't use "Nothing" add to table

 

 

Calvin

[Joe Mamma]

Then again I don't recommend allowing null values into your database

huh???

 

the concept of null is critical!!!!

 

I use it all the time and depend on it for the relational model.

not always but it is often called for and when it is, I accept it.

[Joe Mamma]

try TimeIn = null

sorry about this (what was that about testing code before posting PD???)

 

you want to do this. . .

 

[size=2]Dim [/size][size=2]oTimeIn as = object  = System.DBNull.Value[/size]
' do something to possibly set oTimeIn to an actual date value. . . 
' and set up your update statement
' then . . . 
cmdUpdate.Parameters.Add(new OleDbParameter("@TimeIn", TimeIn))
cmdUpdate.ExecuteNonScalar

 

forget about the spaghetti approach:

if test then 
  this 
else 
 that 
end if

bad. . very bad

 

 

[calvin]

Thanks for help, it works

 

 

Calvin :D

[Joe Mamma]

Thanks for help, it works

 

 

Calvin :D

here to serve. . . and gripe about VB