The UTL_ENCODE.BASE64_DECODE function is part of Oracle’s UTL_ENCODE package, which provides utilities for encoding and decoding binary data. Specifically, the BASE64_DECODE function decodes a Base64-encoded string back into its original binary format. This is commonly used when handling encoded data in applications, such as data transfer, storage, or processing.
Syntax
UTL_ENCODE.BASE64_DECODE(encoded_data IN RAW) RETURN RAW;
Parameters
encoded_data: A RAW datatype input representing the Base64-encoded data to be decoded.
Return Value
Returns a RAW datatype containing the decoded binary data.
Usage Notes
The input data must be in Base64 format and of type RAW. If the input is not properly encoded in Base64, the function may return incorrect results or raise an error.
The output is also in RAW, which can be converted to other formats (e.g., VARCHAR2 or BLOB) depending on the application requirements.
UTL_ENCODE functions are primarily used when working with binary data, such as files, images, or cryptographic operations.
Example 1: Decoding Base64-encoded Data
DECLARE
encoded_data RAW(2000) := UTL_RAW.CAST_TO_RAW('VGhpcyBpcyBhIHRlc3Qu'); -- "This is a test."
decoded_data RAW(2000);
BEGIN
decoded_data := UTL_ENCODE.BASE64_DECODE(encoded_data);
DBMS_OUTPUT.PUT_LINE(UTL_RAW.CAST_TO_VARCHAR2(decoded_data)); -- Converts RAW back to VARCHAR2
END;
/
Output: This is a test.
Example 2: Handling Binary Data
DECLARE
encoded_data RAW(2000) := UTL_RAW.CAST_TO_RAW('U29tZSBiaW5hcnkgZGF0YQ=='); -- "Some binary data"
decoded_data RAW(2000);
BEGIN
decoded_data := UTL_ENCODE.BASE64_DECODE(encoded_data);
-- Example usage: Store or process decoded data
DBMS_OUTPUT.PUT_LINE('Decoded data length: ' || LENGTH(decoded_data));
END;
/
Key Points
Input Restrictions: The input must be Base64-encoded and in RAW format. Use functions like UTL_RAW.CAST_TO_RAW to convert text data if needed.
Output Usage: The output is RAW, which may need conversion to make it human-readable or suitable for further processing.
Common Applications: Useful in web services, cryptographic operations, file handling, or scenarios where Base64 encoding is used for data transmission or storage.
Related Functions
UTL_ENCODE.BASE64_ENCODE: Encodes binary data into Base64 format.
UTL_RAW.CAST_TO_RAW: Converts text to RAW.
UTL_RAW.CAST_TO_VARCHAR2: Converts RAW back to text.
By utilizing UTL_ENCODE.BASE64_DECODE, developers can efficiently handle Base64-encoded data within Oracle PL/SQL programs.