SQL ServerData Types

SQL - DataTypes - Bit

The bit data type is simple - and yet, it gets kind of tricky.

In short - this datatype can be set to 0 or 1.

Two things complicate this:

  • It can also be set to null
  • Many programming languages will set this to true/false

Consequently - it’s pretty easy to fall into some traps.

Here are a few

asp.net sample - populating a checkbox based on a bit field

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ds = dl_db.DS_Fetch(str, "ConnectionString")
chkChlorine.Checked = False  ' here is my checkbox
If ds.Tables(0).Rows.Count = 0 Then
    ' nothing for 
Else
    With ds.Tables(0).Rows(0)
        If .Item("Confined") Then  ' if I said .item("confined")=1, it would never work
            chkConfined.Checked = True
        End If
    End With
End If