Oracle Character Set

When you create a database, you can specify the character set (CHARACTER set) and the national character set (Nation CHARACTER set, additional character set).

1. Character Set:
(1) used to store char, VARCHAR2, CLOB, long and other types of data
(2) to indicate such as table name, column name, and PL/SQL variable, etc.
(3) used to store SQL and PL + + program units, etc.

2. National Character Set:
(1) to store nchar, NVARCHAR2, NCLOB and other types of data
(2) The national character set is essentially the additional character set chosen for Oracle, primarily to enhance the character processing capabilities of Oracle, since the nchar data type provides support for the use of fixed-length multibyte encoding in Asia, and the database character set is not. The national character set is redefined in oracle9i and can only be selected in Af16utf16 and UTF8 in Unicode encoding, and the default value is AF16UTF16.

My database:

Oracle 12c supports a single CDB with multiple PDB, each with a different character set, and multiple character sets can coexist.

Oracle Character Set