How to check the Oracle database character set

Introduction

Character sets are a crucial aspect of Oracle databases, influencing data storage, retrieval, and integrity. Properly setting and verifying your Oracle database’s character set ensures compatibility across different systems and prevents data corruption. This guide will walk you through various methods how to Oracle database character set, including using the NLS_CHARACTERSET and NLS_NCHAR_CHARACTERSET parameters.

Basic Methods to Check Oracle Database Character Set

Using SQL*Plus

One of the simplest ways to check your Oracle database character set is through SQL*Plus. Follow these steps:

Log in to SQL*Plus:

sqlplus username/password@database

Execute the following query:

SELECT parameter, value 
FROM nls_database_parameters 
WHERE parameter = 'NLS_CHARACTERSET';

Using Data Dictionary Views

Oracle provides several data dictionary views that store character set information. The NLS_DATABASE_PARAMETERS view is one such view.

1. Log in to SQL*Plus or any other SQL interface.
2. Run the following query:
   • SELECT * FROM v$nls_parameters WHERE parameter = 'NLS_CHARACTERSET';

Intermediate Methods to Check Oracle Database Character Set

Using DBMS_SESSION Package

The DBMS_SESSION package allows you to access various session-level settings, including character set information.

Run the following PL/SQL block:

DECLARE
l_nls_characterset VARCHAR2(30);
BEGIN
DBMS_SESSION.GET_NLS('NLS_CHARACTERSET', l_nls_characterset);
DBMS_OUTPUT.PUT_LINE('Database Character Set: ' || l_nls_characterset);
END;
/

Checking Character Set in a Multitenant Environment

In a multi-tenant environment, it’s essential to check the character set of each pluggable database (PDB).

1. Connect to the container database (CDB).
   • sqlplus username/password@CDB
2. Query the character set for each PDB:
   • SELECT name, value FROM v$pdbs, v$nls_parameters WHERE parameter = 'NLS_CHARACTERSET' AND con_id = pdb.con_id;

Advanced Methods to Check Oracle Database Character Set

Using Oracle Enterprise Manager

Oracle Enterprise Manager provides a graphical interface to check and manage database settings, including character sets.

1. Log in to Oracle Enterprise Manager.
2. Navigate to the database you want to check.
3. Go to the “Administration” tab and select “NLS Database Parameters.”
4. Check the “NLS_CHARACTERSET” parameter.

Using SQL Developer

Oracle SQL Developer is a powerful tool that allows you to manage database settings graphically.

1. Open Oracle SQL Developer and connect to your database.
2. Navigate to “View” > “DBA.”
3. Expand the “Database” node and select “NLS.”
4. Find the “NLS_CHARACTERSET” parameter.

Checking Both NLS_CHARACTERSET and NLS_NCHAR_CHARACTERSET

To get a complete picture of your Oracle database character settings, you should check both the NLS_CHARACTERSET and NLS_NCHAR_CHARACTERSET parameters. Here’s how you can do it:

Log in to SQL*Plus:

sqlplus username/password@database

Execute the following query to check the NLS_CHARACTERSET:

SELECT PROPERTY_NAME, PROPERTY_VALUE
FROM database_properties
WHERE PROPERTY_NAME = 'NLS_CHARACTERSET';

Screen output:

PROPERTY_NAME                  PROPERTY_VALUE
------------------------------ --------------
NLS_CHARACTERSET               AL32UTF8

Execute the following query to check the NLS_NCHAR_CHARACTERSET:

SELECT PROPERTY_NAME, PROPERTY_VALUE 
FROM database_properties 
WHERE PROPERTY_NAME = 'NLS_NCHAR_CHARACTERSET'; 

Screen output:

PROPERTY_NAME PROPERTY_VALUE

NLS_NCHAR_CHARACTERSET AL16UTF16

Frequently Asked Questions (FAQs)

What is a character set in Oracle?

A character set in Oracle defines the set of characters that can be used in the database, determining how data is stored and retrieved. It includes encoding rules for characters.

Why is it important to check the Oracle database character set?

Checking the Oracle database character set ensures data integrity and compatibility, especially when dealing with multiple languages and diverse systems. It prevents data corruption and ensures seamless data exchange.

How can I change the character set of my Oracle database?

Changing the character set of an Oracle database is a complex process that involves exporting the database, creating a new database with the desired character set, and importing the data. It is recommended to consult Oracle documentation and perform thorough testing.

Can I check the character set using PL/SQL Developer?

Yes, you can use PL/SQL Developer to check the character set. Connect to your database, navigate to “View” > “NLS Parameters,” and find the “NLS_CHARACTERSET” parameter.

What are the common character sets used in Oracle databases?

Common character sets include AL32UTF8, UTF8, WE8ISO8859P1, and WE8MSWIN1252. The choice depends on the languages and data types you need to support.

Conclusion

Through this article, you have learned how to check the Oracle database character set using various methods, including NLS_CHARACTERSET and NLS_NCHAR_CHARACTERSET. Properly identifying and managing your Oracle database character set is essential for maintaining data integrity and compatibility.

By following these steps, you can confidently manage your database settings, ensuring smooth operations and data handling across different systems and languages. I hope this guide is helpful. Thank you for reading the DevopsRoles page!