NLS_LENGTH_SEMANTICS is a database parameter that controls the way that the database calculates the length of character strings. There are two possible values for this parameter: BYTE and CHAR. When NLS_LENGTH_SEMANTICS is set to BYTE, the database calculates the length of a character string in bytes. When NLS_LENGTH_SEMANTICS is set to CHAR, the database calculates the length of a character string in characters.
The default value for NLS_LENGTH_SEMANTICS is BYTE. This means that, by default, the database calculates the length of character strings in bytes. However, there are some cases in which it may be necessary to set NLS_LENGTH_SEMANTICS to CHAR. For example, if you are using a database to store Unicode data, you will need to set NLS_LENGTH_SEMANTICS to CHAR in order to ensure that the database calculates the length of character strings correctly.
