Introduction to Oracle NCHAR Data Type

In Oracle Database, NCHAR is a character data type used to store fixed-length strings in the Unicode character set. Unlike the CHAR type, which uses the character set of the current database, NCHAR type uses the Unicode character set.

Syntax

The following syntax can be used to define a column of NCHAR type when creating a table:

column_name NCHAR(size) [CHARACTER SET Unicode_name]

Where column_name is the name of the column, size is the maximum number of characters for that column, and Unicode_name is the name of the Unicode character set, which defaults to AL16UTF16.

Use Cases

Since NCHAR type supports the Unicode character set, it is suitable for storing data in different languages or special character sets, such as international applications, multilingual websites, etc.

Additionally, since NCHAR type has a fixed length, it is suitable for scenarios where string comparison or sorting is required.

Examples

Here are two examples of using NCHAR type:

Example 1

Create an employees table with a last_name column and a first_name column, both of which are of NCHAR type:

CREATE TABLE employees (
  last_name NCHAR(20),
  first_name NCHAR(10)
);

Insert a record into this table:

INSERT INTO employees VALUES ('Adam', 'Alice');

Query the table:

SELECT * FROM employees;

The result is:

LAST_NAME            FIRST_NAME
-------------------- ----------
Adam                 Alice

Example 2

Create a books table with a title column and an author column, both of which are of NCHAR type:

CREATE TABLE books (
  title NCHAR(50),
  author NCHAR(20)
);