Needed to modify the database table creation as follows:
CREATE TABLE /*_*/transcode (
transcode_id SERIAL PRIMARY KEY,
transcode_image_name VARCHAR(255) NOT NULL,
transcode_key VARCHAR(48) NOT NULL,
transcode_error TEXT NOT NULL,
transcode_time_addjob VARCHAR(14) NULL,
transcode_time_startwork VARCHAR(14) NULL,
transcode_time_success VARCHAR(14) NULL,
transcode_time_error VARCHAR(14) NULL,
transcode_final_bitrate INT NOT NULL
);