NLS_LENGTH_SEMANTICS

Parameter type	String
Syntax	NLS_LENGTH_SEMANTICS = string Example: NLS_LENGTH_SEMANTICS = 'CHAR'
Default value	BYTE
Parameter class	Dynamic: ALTER SESSION, ALTER SYSTEM
Range of values	BYTE | CHAR

NLS_LENGTH_SEMANTICS enables you to create CHAR and VARCHAR2 columns using either byte or character length semantics. Existing columns are not affected.

NCHAR, NVARCHAR2, CLOB, and NCLOB columns are always character-based. You may be required to use byte semantics in order to maintain compatibility with existing applications.

NLS_LENGTH_SEMANTICS does not apply to tables in SYS and SYSTEM. The data dictionary always uses byte semantics.