How to read a very long blob column in oracle?

@lizzie 

To read a very long BLOB column in Oracle, you can use the DBMS_LOB package. Here is an example of how to read a BLOB column with the DBMS_LOB package:

1. Start by selecting the BLOB column from the table:

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SELECT my_blob_column
FROM my_table
WHERE id = 123;

1. Use the DBMS_LOB package to read the BLOB data:

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DECLARE
  l_blob BLOB;
  l_buffer RAW(32767); -- Set the buffer size as needed
  l_amount INTEGER := 32767;
  l_pos INTEGER := 1;
  l_dest_offset INTEGER := 1;
BEGIN
  SELECT my_blob_column
  INTO l_blob
  FROM my_table
  WHERE id = 123;
  
  DBMS_LOB.read(l_blob, l_amount, l_pos, l_buffer);

  DBMS_OUTPUT.put_line(UTL_RAW.CAST_TO_VARCHAR2(l_buffer));
END;

This script will read the BLOB data from the specified table and ID, and output the data as a VARCHAR2 string in the DBMS_OUTPUT. Make sure to adjust the buffer size and data type according to your specific requirements.