What value do NUMBER data type columns return when fully redacted?

When NUMBER data type columns are fully redacted, they return a value of zero (0). This behavior is defined by Oracle's data redaction policy, which ensures that sensitive data, while still accessible in terms of its datatype, does not reveal meaningful information.

The rationale behind returning zero instead of null, an empty string, or no value at all is to provide a consistent output that keeps the integrity of the data type. For instance, if the data type is expected to be a number, returning zero keeps the structure intact while masking the actual value. This approach allows applications that rely on numeric data types to continue functioning without encountering unexpected nulls or data type mismatches that could arise from pushing an empty string or no value.

This mechanism not only protects sensitive information by providing a meaningless value but also avoids creating scenarios where applications might misinterpret absent data as a failure or error in data retrieval. By returning zero in the context of redacted NUMBER data types, Oracle ensures that systems that depend on this data can handle it without issues, thereby facilitating both security and usability within applications.