UPDATE paper_files SET file_type = 'application/pdf' WHERE original_file_name RLIKE '\\.pdf$';
UPDATE paper_files SET file_type = 'application/msword' WHERE original_file_name RLIKE '\\.doc$';
UPDATE paper_files SET file_type = 'application/vnd.ms-powerpoint' WHERE original_file_name RLIKE '\\.ppt$';
UPDATE paper_files SET file_type = 'application/vnd.ms-powerpoint' WHERE original_file_name RLIKE '\\.pps$';
UPDATE paper_files SET file_type = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document' WHERE original_file_name RLIKE '\\.docx$';
UPDATE paper_files SET file_type = 'application/vnd.openxmlformats-officedocument.presentationml.presentation' WHERE original_file_name RLIKE '\\.pptx$';
UPDATE paper_files SET file_type = 'application/vnd.openxmlformats-officedocument.presentationml.slideshow' WHERE original_file_name RLIKE '\\.ppsx$';