You can use the unichar and univarchar datatypes anywhere that you can use char and varchar character datatypes, without having to make syntax changes.
In Adaptive Server version 12.5.1 and later, queries containing character literals that cannot be represented in the server’s character set are automatically promoted to the unichar datatype so you do not have to make syntax changes for data manipulation language (DML) statements. Additional syntax is available for specifying arbitrary characters in character literals, but the decision to “promote” a literal to unichar is based solely on representability.
With data definition language (DDL) statements, the syntax changes required are minimal. For example, in the create table command, the size of a Unicode column is specified in units of 16-bit Unicode values, not bytes, thereby maintaining the similarity between char(200) and unichar(200). sp_help, which reports on the lengths of columns, uses the same units. The multiplication factor (2) is stored in the new global variable @@unicharsize.
See Chapter 8, “Configuring Character Sets, Sort Orders, and Languages,” in the System Administration Guide for more information about Unicode.
