Nulls Require Variable-Length Datatypes

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

This table lists the fixed-length datatypes and the variable-length datatypes to which SAP ASE converts them. Certain variable-length datatypes, such as moneyn, are reserved; you cannot use them to create columns, variables, or parameters.

Original Fixed-Length Datatype	Converted to
`char`	`varchar`
`nchar`	`nvarchar`
`unichar`	`univarchar`
`binary`	`varbinary`
`datetime`	`datetimn`
`float`	`floatn`
`bigint`, `int`, `smallint`, `tinyint`,	`intn`
`unsigned bigint`, `unsigned int`, and`unsigned smallint`	`uintn`
`decimal`	`decimaln`
`numeric`	`numericn`
`money` and `smallmoney`	`moneyn`

Data entered into char, nchar, unichar, and binary columns follows the rules for variable-length columns, rather than being padded with spaces or zeros to the full length of the column specification.