NCHAR(n) data type

The NCHAR data type stores fixed-length character data. The data can be a string of single-byte or multibyte letters, digits, and other symbols that are supported by the code set of the database locale.

The main difference between CHAR and NCHAR data types is the collating order.

The collation order of the CHAR data type follows the code-set order, but the collating order of the NCHAR data type can be a localized order, if DB_LOCALE (or SET COLLATION) specifies a locale that defines a localized order for collation.

Size specifications ib NCHAR data type declarations can be affected by the SQL_LOGICAL_CHAR configuration parameter that is described in the section Logical Character Semantics in Character Type Declarations.

In databases that are created with the NLSCASE INSENSITIVE property, operations on NCHAR strings ignore letter case, ordering data values without respect to or preference for letter case. For example, the NCHAR string "IDS" might precede or follow "IdS" or "iDs" in the collated list that a query returns, depending on the order in which these data strings are retrieved, because all of the following NCHAR strings are treated as duplicate values:
"ids" "IDS" "idS" "IDs" "IdS" "iDs" "iDS" "Ids"