ALTER TABLE tg_file ADD original_name VARCHAR(255) DEFAULT NULL, ADD mime_type VARCHAR(255) DEFAULT NULL;
UPDATE tg_file SET original_name = SUBSTRING(name FROM 15);
UPDATE tg_file SET mime_type = 'image/png' WHERE LOWER(SUBSTRING(original_name FROM LENGTH(original_name) - 3)) = '.png';
UPDATE tg_file SET mime_type = 'image/jpeg' WHERE LOWER(SUBSTRING(original_name FROM LENGTH(original_name) - 3)) = '.jpg';
UPDATE tg_file SET mime_type = 'image/jpeg' WHERE LOWER(SUBSTRING(original_name FROM LENGTH(original_name) - 4)) = '.jpeg';
UPDATE tg_file SET mime_type = 'image/gif' WHERE LOWER(SUBSTRING(original_name FROM LENGTH(original_name) - 3)) = '.gif';
UPDATE tg_file SET mime_type = 'application/pdf' WHERE LOWER(SUBSTRING(original_name FROM LENGTH(original_name) - 3)) = '.pdf';
ALTER TABLE tg_file ALTER mime_type SET NOT NULL, ALTER mime_type DROP DEFAULT, ALTER original_name SET NOT NULL, ALTER original_name DROP DEFAULT;
ALTER TABLE tg_file ADD original_name VARCHAR(255) DEFAULT NULL, ADD mime_type VARCHAR(255) DEFAULT NULL;
UPDATE tg_file SET original_name = SUBSTRING(name FROM 14);
UPDATE tg_file SET mime_type = 'image/png' WHERE LOWER(SUBSTRING(original_name FROM -4)) = '.png';
UPDATE tg_file SET mime_type = 'image/jpeg' WHERE LOWER(SUBSTRING(original_name FROM -4)) = '.jpg';
UPDATE tg_file SET mime_type = 'image/jpeg' WHERE LOWER(SUBSTRING(original_name FROM -5)) = '.jpeg';
UPDATE tg_file SET mime_type = 'image/gif' WHERE LOWER(SUBSTRING(original_name FROM -4)) = '.gif';
UPDATE tg_file SET mime_type = 'application/pdf' WHERE LOWER(SUBSTRING(original_name FROM -4)) = '.pdf';
ALTER TABLE tg_file CHANGE mime_type mime_type VARCHAR(255) NOT NULL, CHANGE original_name original_name VARCHAR(255) NOT NULL;