Direction
A direction is a music_data record with a discrminator value of direction.
A direction consists of one or more direction type lists, each having its own direction_type_list record joined to the music_data table.
direction
Direction Type
The direction types themselves are in table direction_type with each record joined to its list in the direction_type_list table. Table direction_type is a single-inheritance table with discriminator column direction_type_type.
Direction type discriminator values
Discriminator values are in most cases the lower-case name of the subelement of the direction-type element with spaces in the place of dashes. Examples: segno and octave shift.
Metronome markings
Beat metronomes consist of a music_data record with discriminator value beat metronome joined to two metronome_mark records joined on columns metronome_mark_1_id and metronome_mark_2_id.
Note metronomes consist of a music_data record with discrminator value note metronome joined to two lists of metronome_note records, the first list joined on metronome_note.note_metronome_1_id, and the second list joined on metronome_note.note_metronome_2_id. Beams, tuplet, and time modification relations are shown in the diagram below.
direction type