About Null/Blank/Empty fields

When looking at any field value that has not value (appears blank) - either in an Outlook contact item or in the input data file, it is impossible to know what the actual value of that field contains which can have a significant impact on how fields are evaluated.

In terms of <text> fields - there are 4 possible "value states"

#1 - Blank

Represents any field that contains one or more space characters in the field value. It is also important to note that a field that contains <one> space character is NOT equal to one that contains <two or more> space characters.

#2 - Blank (unprintable - not-viewable)

Represents any field that contains one or more characters that are not displayed - i.e. a <Tab> character

#3 - Empty

Represents a text field that has been <initialized> but contains no characters

#4 - Null

Represents a field that has not been initialized and is considered to contained <NO> value at all (otherwise referred to as <Nothing>). For example, a Yes/No field can have one of three values, <Yes>, <No> or <NO value = Null).

This becomes important when two fields are compared that both appear as <blank> fields from a visual perspective. Using the definitions above - some exapmples of comparisons would fail are:

FldA = Blank and FldB = Blank (not-viewable) (not equal)

FldA = Blank and FldB = Empty (not equal)

FldA = Blank and FldB = Null (not equal)

FldA = Empty and FldB = Null (not equal)

This becomes particularly relevant in how QuickPort processes <updates> between an Outlook contact folder and various input file types see How the Update Process Works