Oracle NLS_NCHAR_CHARACTERSET: National Character Set Configuration

NLS_NCHAR_CHARACTERSET is a parameter in Oracle Database that specifies the character set for the National Character Set (NCHAR) data type. The National Character Set is used to store national language data that may require a different character set than the database's default character set.

The value of NLS_NCHAR_CHARACTERSET determines the character set used for NCHAR data, which includes NCHAR, NVARCHAR2, and NCLOB data types. It is important to set this parameter correctly in order to ensure proper storage and retrieval of national language data.

The default value for NLS_NCHAR_CHARACTERSET is derived from the database's default character set, but it can be explicitly set during database creation or altered later using the ALTER DATABASE statement.

It is important to note that changing the value of NLS_NCHAR_CHARACTERSET after data has been stored in the database can lead to data corruption, as the character set conversion may not be accurate. Therefore, it is recommended to set this parameter correctly from the beginning and avoid changing it later unless absolutely necessary.