The SQL language provides various data types to store different types of data in a database. Two commonly used data types for storing character data are VARCHAR and VARCHAR2.
While they may seem similar, there are some important differences between them. In this article, we will explore the distinctions between VARCHAR and VARCHAR2 in SQL.
Difference in Storage Capacity
One of the main differences between the VARCHAR and VARCHAR2 data types is their storage capacity.
The VARCHAR data type allows you to define a column or variable with a maximum length of characters specified. For example, if you define a column as VARCHAR(20), it can store up to 20 characters.
On the other hand, the VARCHAR2 data type also allows you to define a column or variable with a maximum length of characters specified. However, unlike VARCHAR, when you declare a column as VARCHAR2(20), it will allocate space for 20 characters regardless of whether you use all of it or not.
Treatment of Trailing Spaces
An important distinction between VARCHAR and VARCHAR2 is how they handle trailing spaces.
In the case of VARCHAR, trailing spaces are not significant. This means that if you store a value with trailing spaces, SQL will ignore them when comparing or displaying the data. For example, “John” and “John ” (with multiple trailing spaces) would be considered equal when compared using VARCHAR.
VARCHAR2, on the other hand, treats trailing spaces as significant. This means that if you store a value with trailing spaces in a VARCHAR2 column and compare it with another value without trailing spaces, they would be considered different.
VARCHAR is a data type that is supported by many database systems, including Oracle. However, it is important to note that VARCHAR2 is specific to the Oracle database.
If you are developing an application that needs to be portable across different database systems, using VARCHAR instead of VARCHAR2 would be a more suitable choice.
In summary, while both VARCHAR and VARCHAR2 are used for storing character data in SQL, there are key differences between them. VARCHAR allows for variable-length storage with trailing spaces being insignificant, while VARCHAR2 allocates space for the maximum length specified and treats trailing spaces as significant. Additionally, VARCHAR is more portable across different database systems compared to the Oracle-specific VARCHAR2.
Understanding these differences will help you make informed decisions when designing your database schema or writing SQL queries.