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Difference Between VARCHAR and VARCHAR2

Difference Between VARCHAR and VARCHAR2

Q: 1. What is the primary difference between VARCHAR and VARCHAR2 in Oracle?

In Oracle, both VARCHAR and VARCHAR2 are used to store variable-length character strings. However, VARCHAR is a reserved keyword and is currently synonymous with VARCHAR2. Oracle plans to redefine VARCHAR in future releases, potentially altering its behavior. Therefore, it's recommended to use VARCHAR2 to ensure consistent behavior across Oracle versions.

Q: 2. Why does Oracle recommend using VARCHAR2 over VARCHAR?

Oracle advises against using VARCHAR because it's reserved for future use and may be redefined to have different comparison semantics, particularly concerning the treatment of empty strings and NULL values. Using VARCHAR2 ensures that your applications remain stable and compatible with future Oracle versions.

Q: 3. How does Oracle handle empty strings in VARCHAR2 columns?

In Oracle, empty strings ('') are treated as NULL in VARCHAR2 columns. This behavior is consistent across Oracle versions and differs from some other databases where empty strings and NULL are distinct.

Q: 4. What are the maximum lengths for VARCHAR2 columns in Oracle?

The maximum length for a VARCHAR2 column in Oracle depends on the MAX_STRING_SIZE parameter:Standard size: Up to 4,000 bytesExtended size: Up to 32,767 bytesTo use the extended size, MAX_STRING_SIZE must be set to EXTENDED, and the database must be configured accordingly.

Q: 5. What is the difference between VARCHAR2(10) and VARCHAR2(10 CHAR)?

VARCHAR2(10) uses the default length semantics defined by the NLS_LENGTH_SEMANTICS parameter, which is typically BYTE. This means the column can store up to 10 bytes. In contrast, VARCHAR2(10 CHAR) explicitly specifies that the column can store up to 10 characters, regardless of how many bytes each character uses. This distinction is crucial when working with multibyte character sets.

Q: 6. Is it advisable to define VARCHAR2 columns with large sizes, like VARCHAR2(4000), if only small strings are stored?

Defining VARCHAR2 columns with large sizes doesn't inherently waste storage, as Oracle stores only the actual length of the data. However, excessively large column definitions can lead to inefficient memory usage in applications and may affect performance during data retrieval. It's best to define column sizes that closely match the expected data length.

Q: 7. Can VARCHAR2 columns be indexed in Oracle?

Yes, VARCHAR2 columns can be indexed in Oracle. However, it's essential to consider the length and uniqueness of the data. Indexing very long VARCHAR2 columns or columns with low cardinality (few unique values) may not provide performance benefits and could increase storage requirements.

Q: 8. How does Oracle compare VARCHAR2 values?

Oracle compares VARCHAR2 values using non-padded comparison semantics. This means that trailing spaces are considered significant, and two strings are equal only if they have the same length and content, including spaces

Q: 9. Is there any performance difference between CHAR and VARCHAR2 in Oracle?

While both CHAR and VARCHAR2 are stored similarly, CHAR pads the data with spaces to match the defined length, which can lead to unnecessary storage and potential performance issues during comparisons. VARCHAR2 stores data without padding, making it more efficient for variable-length data.

Q: 10. Can VARCHAR2 columns be used in partitioned tables?

Yes, VARCHAR2 columns can be used in partitioned tables in Oracle. However, there are restrictions on the length of the column when used as a partition key. It's essential to consult Oracle's documentation for specific limitations and best practices.

By Mukesh Kumar

Updated on Apr 22, 2025 | 6 min read | 1.4k views

Table of Contents

What if using the wrong data type caused unexpected behavior in your Oracle database? That’s exactly what can happen if you confuse VARCHAR with VARCHAR2.

In SQL, both VARCHAR and VARCHAR2 are used to store variable-length character strings. However, in Oracle, there's a crucial distinction: VARCHAR is a reserved keyword and behaves differently across versions, while VARCHAR2 is the standard and recommended data type for storing variable-length character data.

The most important difference? VARCHAR is deprecated and might change behavior in future Oracle versions, whereas VARCHAR2 is fully supported and stable.

In this blog, we’ll break down what VARCHAR and VARCHAR2 are, how they differ in syntax and storage, why Oracle prefers VARCHAR2, and when and how to use it correctly in your database applications.

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Key Differences Between VARCHAR and VARCHAR2

Parameter	VARCHAR	VARCHAR2
Full Form	Variable Character	Variable Character 2
Usage in Oracle	Reserved for future use	Actively used and recommended
Current Support	Deprecated and discouraged	Fully supported
Default Mapping	Internally maps to VARCHAR2	Native Oracle datatype
Storage Allocation	Variable-length (same as VARCHAR2)	Variable-length (stores only actual data size)
Maximum Size	Same as VARCHAR2 (treated as such)	Up to 4,000 bytes in SQL, 32,767 in PL/SQL
NULL Handling	Treated the same as VARCHAR2 (currently)	NULL and empty string treated as the same
Future Compatibility	May change in future Oracle versions	Safe and consistent across versions
ANSI Compliance	Based on ANSI SQL standard	Oracle-specific extension
Documentation Status	Not recommended in Oracle documentation	Well-documented and supported
Preferred For Use?	No	Yes
Semantic Support	Byte semantics only	Byte and character semantics
Behavior Stability	Unstable (may change)	Stable

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What is VARCHAR?

The VARCHAR data type stands for Variable Character and is used to store character strings of variable length. It allows you to define a maximum number of characters, but only uses storage space for the actual length of the data inserted—making it more efficient than fixed-length types like CHAR.

VARCHAR(20)

This allows up to 20 characters, but if you store "Hello", it only uses space for 5 characters (plus a byte for length).

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What is VARCHAR2?

VARCHAR2 is Oracle’s official data type for storing variable-length character strings. Like VARCHAR, it allows you to define a maximum length, but it dynamically allocates storage based on the actual length of the input data.

VARCHAR2(50)

This stores strings up to 50 characters, but only consumes space for the characters you input—plus 1 or 2 bytes to store the length, depending on how many bytes the string contains.

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Why It's Preferred Over VARCHAR

Oracle explicitly recommends VARCHAR2 because:

VARCHAR is reserved for future changes and may not always behave the same.
VARCHAR2 is guaranteed to behave consistently across versions.
It's optimized for performance and fully documented for production use.

In short: VARCHAR2 is safe, stable, and future-proof, making it the preferred choice for storing variable-length strings in Oracle.

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Common Use Cases for VARCHAR2

VARCHAR2 is one of the most frequently used datatypes in Oracle-based applications, thanks to its efficiency, flexibility, and support for variable-length text storage. Here are some real-world use cases:

1. Storing Usernames or Email Addresses

These vary in length but rarely exceed a certain limit.

username VARCHAR2(50),

email VARCHAR2(100)

2. Product Descriptions in E-commerce

Descriptions can be short or long, and VARCHAR2 saves space by storing only actual content.

product_description VARCHAR2(1000)

3. Customer Feedback or Comments

User-submitted content often varies in length and is a perfect fit for VARCHAR2.

customer_review VARCHAR2(2000)

4. Storing URLs or File Paths

These entries are variable by nature and benefit from dynamic length allocation.

image_url VARCHAR2(255)

5. Mobile Numbers or Contact Details

While consistent in format, they’re stored as strings to preserve formatting and prevent mathematical operations.

contact_number VARCHAR2(15)

6. Employee Designation or Role

Job titles differ greatly in length and frequency, making fixed-length storage inefficient.

designation VARCHAR2(100)

7. Audit Trail and Logging

For storing metadata or logs in admin/audit tables.

action_summary VARCHAR2(500),

ip_address VARCHAR2(45)

8. Flexible Metadata Fields

When a field's content is semi-structured or varies across entries.

custom_metadata VARCHAR2(2000)

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Conclusion: Which One Should You Use?

If you’re working with Oracle databases, the answer is clear—always use VARCHAR2, never VARCHAR.

While both may behave the same today, VARCHAR is a reserved keyword and could be redefined in future Oracle releases. Using it risks unexpected behavior, compatibility issues, and unnecessary maintenance headaches down the line.

VARCHAR2, on the other hand, is:

Fully supported and documented by Oracle
Stable across all versions
Optimized for variable-length character data
Capable of handling both byte and character semantics

From a performance, compatibility, and future-proofing perspective, VARCHAR2 is the only safe and recommended choice.

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