VARCHAR and NVARCHAR are two different types of character storage used in SQL databases. VARCHAR stores characters in variable-length strings, meaning each character takes up one byte, whereas NVARCHAR stores characters in two bytes. As a result, NVARCHAR allows for the storage of more characters.
Both types of character storage are essential for many organizations when designing SQL databases for their applications. By understanding the difference between VARCHAR and NVARCHAR, you can determine which character storage type best suits your application needs.
Let’s break them down below!
VARCHAR vs. NVARCHAR: Side-by-Side Comparison
| VARCHAR | NVARCHAR | |
|---|---|---|
| Data Storage | Only stores ASCII characters and requires less storage space | Requires more space to store different character |
| Performance | More efficient in terms of storage and retrieval speed | The larger size can result in increased memory usage and slower query execution times |
| Compatibility | Most programming languages support VARCHAR | Lacks the backing of some database management systems or programming languages |
| Query Optimization | Less storage space makes optimizing queries involving VARCHAR data easier for SQL Server | Double-byte encoding can slow the query processing time and make it harder for SQL Server to optimize queries |
| Character Encoding | Stores ASCII characters, including alphabets, numbers, and special characters | Supports Unicode encoding, which can encode characters from multiple languages like non-Latin-based languages |
| Maximum Length of Characters | Between 1 and 8,000 characters; takes the real length in bytes | Between 1 and 4,000 characters; takes two times the actual length in bytes |
| Character Data Type | Variable-length and non-Unicode (English characters) | Unicode characters such as Korean, Japanese, or Indonesian |
| Literals | It is enclosed in single quotes like ‘John Doe’ | It is prefixed with N, for instance, N’John Doe’ |
What is VARCHAR?
VARCHAR, an acronym for “Variable Character,” is an efficient and flexible data type used in relational databases to store strings of characters with varying lengths. It is a great choice for character data storage as it can accommodate a wide range of characters while also being space-saving.
VARCHAR can store any character data, such as letters, numbers, and special characters. The maximum length you can store in a VARCHAR column varies depending on the database management system. However, in many database systems, the maximum length of a VARCHAR column ranges from 255 to 65,535 characters.
Additionally, VARCHAR is an efficient way to store data since it does not require a fixed amount of space for each column. Instead, it stores only the length of the string, allowing for more effective use of storage space. This makes VARCHAR a great choice for storing data that doesn’t have a fixed length.
What is NVARCHAR?
NVARCHAR is a data type used in relational databases to store variable-length Unicode character strings. NVARCHAR can store characters from different languages, including non-Latin-based languages. NVARCHAR accommodates characters from various languages whose length is not predetermined. It works by allocating the necessary memory for the data based on its size, allowing for a variable-length format. This makes it an ideal choice for storing character information that may vary in length.
Using NVARCHAR provides more encoding options for characters, allowing data to be stored in multiple languages, including those with non-Latin alphabets such as Arabic, Chinese, and Japanese.
Moreover, NVARCHAR is becoming increasingly popular as businesses become more global and require support for multiple languages. However, it does require more storage space than VARCHAR due to its support of Unicode characters. Nevertheless, the benefits of NVARCHAR outweigh the cost of additional storage space in many cases.
VARCHAR vs. NVARCHAR: What’s the Difference?
VARCHAR stores non-Unicode characters, while NVARCHAR is designed to store Unicode characters. Due to the extra encoding feature that stores Unicode data, NVARCHAR requires more storage space than VARCHAR.
It is important to consider the key differences between these two variable-length data types when deciding which one to use. Now let’s look at their distinctions in more detail.
Character Data Type
NVARCHAR is a data type that can store both English and non-English character data types, ASCII values, and special characters. This makes it ideal for multi-lingual applications, supporting up to 4,000 characters. On the other hand, VARCHAR is mainly used for storing English character data types and can hold up to 8,000 characters with ASCII support.
Literals
The main difference between VARCHAR and NVARCHAR lies in their handling of characters. VARCHAR values or literals are enclosed in single inverted commas, such as VALUES (‘Substantive’). On the other hand, NVARCHAR values or literals require an additional prefix of ‘N’ within the single inverted commas. An example is VALUES (N’Substantive’). Using the N prefix indicates that the value is Unicode, a character set that includes many international characters. As a result, NVARCHAR values can accommodate a broader range of characters, while VARCHAR can only store up to 255 characters.
Data Storage
VARCHAR stores variable-length character strings, where the length of the stored data determines the storage size. The maximum length it can store in a VARCHAR column differs depending on the database management system. In many database systems, a VARCHAR column can have a maximum length of 255 to 65,535 characters.
On the other hand, NVARCHAR stores variable-length Unicode character strings. Unlike VARCHAR, it can store characters from different languages, including non-Latin-based ones. The length of the stored data also determines the storage size of NVARCHAR. However, because NVARCHAR supports Unicode encoding, it requires more storage space than VARCHAR.
Character Encoding
VARCHAR stores ASCII characters, including alphabets, numbers, and special characters. ASCII is a 7-bit character set that is capable of encoding 127 characters. While this character set is sufficient for most English-based languages, it cannot represent characters from other languages, such as Chinese or Arabic.
On the other hand, NVARCHAR supports Unicode encoding, which can encode characters from multiple languages. Unicode is a character set that can encode up to 1.1 million character points. Such properties make NVARCHAR an ideal data type for storing data because it lacks a fixed length and can contain characters from different languages.
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Performance
VARCHAR is a more efficient choice for data storage due to its ability to store only ASCII characters and its reduced memory requirements. This design allows VARCHAR to occupy less space than NVARCHAR, resulting in faster retrieval and storage speeds. This feature necessitates faster query times and better overall performance.
On the other hand, NVARCHAR requires more storage space than VARCHAR due to its ability to store Unicode characters, resulting in slower query times and overall performance compared to VARCHAR. Nevertheless, the difference in performance between the two data types may be insignificant in smaller databases or when there is a minimal amount of stored data.
Use Cases
VARCHAR is an ideal data type for storing only ASCII characters, such as names, addresses, and descriptions. It is advantageous to use VARCHAR since it utilizes storage space efficiently due to its variable-length storage format and can store data that frequently changes.
On the other hand, NVARCHAR is suitable for storing data with no fixed length, which may contain characters from different languages. For instance, NVARCHAR is an ideal data type for storing text-based information such as text messages, emails, and social media posts. It can also store web content or documents in multiple languages since it supports multi-lingual data.
Compatibility
VARCHAR is a popular data type in relational databases, supported by most database management systems. Furthermore, it can be easily integrated into different applications as many programming languages support it.
On the other hand, if an application only supports ASCII characters, it can be challenging to incorporate NVARCHAR since some database management systems or programming languages may not support it. This design limitation can make adding NVARCHAR to the application a challenge.
Storage Requirements
The difference in storage space between VARCHAR and NVARCHAR results from their respective encoding schemes. VARCHAR uses a single-byte encoding scheme, which requires one byte of storage for each character.
In contrast, NVARCHAR uses a double-byte encoding scheme that takes up more memory to support Unicode characters. Such a requirement needs two bytes of storage for each character. Typically, for the same amount of character data, NVARCHAR needs twice the storage space of VARCHAR. Therefore, when designing a database, it is crucial to consider the trade-off between the flexibility of NVARCHAR and the storage efficiency of VARCHAR.
Query Optimization
VARCHAR has the edge over NVARCHAR regarding query optimization due to its lower storage requirements. VARCHAR requires fewer resources for processing than NVARCHAR, which uses double-byte encoding and thus requires more resources for the same amount of data. This makes it easier for SQL server to optimize queries involving VARCHAR data. In contrast, queries with NVARCHAR data can be slowed down by the additional processing time required and may not be as easily optimized by SQL server.
When considering between VARCHAR and NVARCHAR data types for a database, it is important to consider how each will affect performance. If speed is your main concern, VARCHAR may be more suitable. On the other hand, if you require multi-language support, then NVARCHAR would be the best choice.
VARCHAR vs. NVARCHAR: 8 Must-Know Facts
- VARCHAR stands for “Variable Character.” It stores variable-length Unicode character strings.
- NVARCHAR stands for “National Variable Character,” and it stores characters of varying lengths, including those from multiple languages such as non-Latin-based ones.
- VARCHAR uses a single-byte character encoding system to store data.
- NVARCHAR employs a double-byte character encoding system.
- VARCHAR can store names, addresses, and descriptions.
- NVARCHAR can store text messages, emails, and social media posts.
- VARCHAR only writes ASCII values. The characters in ASCII are 256.
- NVARCHAR stores Unicode values, which are more than 256 ASCII characters.
VARCHAR vs. NVARCHAR: Which One Should You Use?
When deciding between VARCHAR and NVARCHAR, it is essential to consider your project’s requirements. NVARCHAR is a variable-length character data type that utilizes double-byte encoding. On the other hand, VARCHAR is a fixed-length character data type that uses single-byte encoding for Unicode characters.
VARCHAR may be more suitable if your project only needs to operate with single-byte character sets. Additionally, VARCHAR is a popular data type that takes up less storage space and is faster than NVARCHAR regarding query optimization.
However, NVARCHAR may be needed if your project requires Unicode characters or support for multiple languages. It also supports more languages and character sets than VARCHAR, which can be important for global applications. Even though it uses more storage space than VARCHAR, it still offers high-quality results since it can accommodate various characters and symbols.
If you need to support multiple languages and character sets, then NVARCHAR may be the better option. However, if single-byte character sets are sufficient and storage space is a priority, VARCHAR might be a more suitable solution. Ultimately, it all comes down to what best meets your needs.
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