What Is Character Data Type in Oracle?

A character data type is a fundamental concept in Oracle databases. It represents any string of characters, such as letters, numbers, or special symbols. In Oracle, there are different character data types available to accommodate various requirements.

Character Data Types in Oracle:

1. CHAR:
The CHAR data type is used to store fixed-length character strings.

When you define a CHAR column, you must specify the maximum length of the string it can hold. For example:

CREATE TABLE employees
(
employee_id NUMBER,
first_name CHAR(50),
last_name CHAR(50)
);

In this example, the first_name and last_name columns can hold strings up to 50 characters long.

2. VARCHAR2:
The VARCHAR2 data type is used to store variable-length character strings.

Unlike the CHAR data type, VARCHAR2 columns only occupy space for the actual length of the stored string plus two bytes for overhead. For example:

CREATE TABLE customers
(
customer_id NUMBER,
first_name VARCHAR2(100),
last_name VARCHAR2(100)
);

Here, the first_name and last_name columns can hold strings up to 100 characters long.

3. NCHAR:
The NCHAR data type is similar to CHAR but is used to store fixed-length Unicode character strings (National Character Set). It is useful when dealing with multilingual data that requires support for different character sets.

4. NVARCHAR2:
The NVARCHAR2 data type is similar to VARCHAR2 but is used to store variable-length Unicode character strings (National Character Set). It allows storing multilingual data in Oracle databases.

Usage Examples:

Let’s consider an example where we want to create a table to store employee information:

CREATE TABLE employees
(
employee_id NUMBER,
first_name VARCHAR2(50),
last_name VARCHAR2(50)
);

• The employee_id column is of type NUMBER, which stores numeric values.
• The first_name and last_name columns are of type VARCHAR2, which can hold variable-length character strings.

By utilizing appropriate character data types, we can ensure efficient storage and retrieval of data in the Oracle database.

In conclusion, the character data type in Oracle is essential for storing strings of characters. By using the appropriate data type based on our requirements, we can efficiently manage and manipulate textual data within Oracle databases.