What Is a Boolean Data Type and What Is It Called in Oracle SQL Server and Access?


Heather Bennett

Boolean data type is a fundamental concept in computer programming and database management. It represents a binary value that can be either true or false. Boolean data types are commonly used to store and manipulate logical values, such as whether a condition is met or not.

In Oracle SQL Server, the equivalent data type for boolean is called BOOLEAN. It is a simple and straightforward data type that can hold true or false values. When querying or manipulating data in Oracle SQL Server, you can use boolean expressions to perform logical operations.

In Access, however, there is no specific boolean data type like in Oracle SQL Server. Instead, Access uses a variant of the YES/NO data type to represent boolean values. The YES/NO data type allows you to store either True (yes) or False (no) values.

  • The BOOLEAN Data Type in Oracle SQL Server:

  • The BOOLEAN data type in Oracle SQL Server is typically used in conjunction with conditional statements and logical operations. It allows you to evaluate conditions and make decisions based on the result.

  • The YES/NO Data Type in Access:

  • In Access, the YES/NO data type serves as a substitute for the boolean data type. It allows you to store true/false values but uses different keywords.

Differences Between BOOLEAN in Oracle SQL Server and YES/NO in Access:

Data Storage:

In Oracle SQL Server, the BOOLEAN data type occupies 1 byte of storage space. It stores its value internally as a single-byte code representing true or false.

In contrast, the YES/NO data type in Access occupies only 1 bit of storage space. This means that it can only hold two values – true or false.

Usage in Queries:

When querying data in Oracle SQL Server, you can use boolean expressions directly in your SQL statements. For example, you can use the AND, OR, and NOT operators to combine boolean conditions.

In Access, boolean values are typically used in queries by comparing them to other values. For example, you might use the YES/NO data type to filter records based on whether a certain condition is met.


In Oracle SQL Server, boolean values are often represented as 1 for true and 0 for false. However, it’s important to note that different database systems may handle boolean representation differently.

In Access, boolean values are represented as -1 for true and 0 for false. This representation is consistent across different versions of Access.


In summary, while Oracle SQL Server has a specific BOOLEAN data type for storing and manipulating boolean values, Access uses the YES/NO data type as an equivalent substitute. Both data types allow you to work with logical values but have slight differences in their implementation.

Understanding how boolean data types work in different database systems is essential for writing efficient queries and performing logical operations on your data.

Now that you have a better understanding of what a boolean data type is and how it is called in Oracle SQL Server and Access, you can confidently utilize these concepts in your programming and database management endeavors.

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