Automatic conversion of fixed-length NULL columns

Only columns with variable-length datatypes can store null values. When you create a NULL column with a fixed-length datatype, Adaptive Server automatically converts it to the corresponding variable-length datatype. Adaptive Server does not inform the user of the datatype change.

Table 1-4 lists the fixed- and variable-length datatypes to which they are converted. Certain variable-length datatypes, such as moneyn, are reserved datatypes; you cannot use them to create columns, variables, or parameters:

Table 1-4: Automatic conversion of fixed-length datatypes

Original fixed-length datatype

Converted to

char

varchar

unichar

univarchar

nchar

nvarchar

binary

varbinary

datetime

datetimn

date

daten

time

timen

float

floatn

int, smallint, and tinyint

intn

decimal

decimaln

numeric

numericn

money and smallmoney

moneyn