Structuri ierarhice Stocarea şi utilizarea arborilor în baze de date

Structuri ierarhice Electronice Monitoare Aparate foto CRT LCD Compacte SLR Digitale Pe film

Reprezentare recursivă +-------------+----------------------+--------+ | category_id | name | parent | +-------------+----------------------+--------+ | 1 | Electronice | NULL | | 2 | Monitoare | 1 | | 3 | CRT | 2 | | 4 | LCD | 2 | | 5 | Aparate foto | 1 | | 6 | SLR | 5 | | 7 | Digitale | 6 | | 8 | Pe film | 6 | | 9 | Compacte | 5 | +-------------+----------------------+--------+

+-------------+----------------------+--------+

| category_id | name | parent |

+-------------+----------------------+--------+

| 1 | Electronice | NULL |

| 2 | Monitoare | 1 |

| 3 | CRT | 2 |

| 4 | LCD | 2 |

| 5 | Aparate foto | 1 |

| 6 | SLR | 5 |

| 7 | Digitale | 6 |

| 8 | Pe film | 6 |

| 9 | Compacte | 5 |

+-------------+----------------------+--------+

Reprezentare plană +-------------+----------------------+--------+------+-------+ | category_id | name | parent | rank | depth | +-------------+----------------------+--------+------+-------+ | 1 | Electronice | NULL | 1 | 0 | | 2 | Monitoare | 1 | 2 | 1 | | 3 | CRT | 2 | 3 | 2 | | 4 | LCD | 2 | 4 | 2 | | 5 | Aparate foto | 1 | 5 | 1 | | 6 | SLR | 5 | 6 | 2 | | 7 | Digitale | 6 | 7 | 3 | | 8 | Pe film | 6 | 8 | 3 | | 9 | Compacte | 5 | 9 | 2 | +-------------+----------------------+--------+------+-------+

+-------------+----------------------+--------+------+-------+

| category_id | name | parent | rank | depth |

+-------------+----------------------+--------+------+-------+

| 1 | Electronice | NULL | 1 | 0 |

| 2 | Monitoare | 1 | 2 | 1 |

| 3 | CRT | 2 | 3 | 2 |

| 4 | LCD | 2 | 4 | 2 |

| 5 | Aparate foto | 1 | 5 | 1 |

| 6 | SLR | 5 | 6 | 2 |

| 7 | Digitale | 6 | 7 | 3 |

| 8 | Pe film | 6 | 8 | 3 |

| 9 | Compacte | 5 | 9 | 2 |

+-------------+----------------------+--------+------+-------+

Reprezentare lineară +-------------+----------------------+-------- - ------ - -------+ | category_id | name | tree_path | +-------------+----------------------+-------- - ------ - -------+ | 1 | Electronice | 001 | | 2 | Monitoare | 001.001 | | 3 | CRT | 001.001.001 | | 4 | LCD | 001.001.002 | | 5 | Aparate foto | 001.00 2 | | 6 | SLR | 001.002.001 | | 7 | Digitale | 001.002.001.001 | | 8 | Pe film | 001.002. 001. 002 | | 9 | Compacte | 001.002.00 2 | +-------------+----------------------+-------- - ------ - -------+

+-------------+----------------------+-------- - ------ - -------+

| category_id | name | tree_path |

+-------------+----------------------+-------- - ------ - -------+

| 1 | Electronice | 001 |

| 2 | Monitoare | 001.001 |

| 3 | CRT | 001.001.001 |

| 4 | LCD | 001.001.002 |

| 5 | Aparate foto | 001.00 2 |

| 6 | SLR | 001.002.001 |

| 7 | Digitale | 001.002.001.001 |

| 8 | Pe film | 001.002. 001. 002 |

| 9 | Compacte | 001.002.00 2 |

+-------------+----------------------+-------- - ------ - -------+

Reprezentare preordonată Electronice Monitoare Aparate foto CRT LCD Compacte SLR Digitale Pe film 1 2 3 4 5 6 7 18 8 9 10 11 15 16 12 13 14 17

Reprezentare preordonată +-------------+----------------------+-----+-----+ | category_id | name | lft | rgt | +-------------+----------------------+-----+-----+ | 1 | Electronice | 1 | 18 | | 2 | Monitoare | 2 | 7 | | 3 | CRT | 3 | 4 | | 4 | LCD | 5 | 6 | | 5 | Aparate foto | 8 | 17 | | 6 | SLR | 9 | 14 | | 7 | Digitale | 10 | 11 | | 8 | Pe film | 12 | 13 | | 9 | Compacte | 15 | 16 | +-------------+----------------------+-----+-----+

+-------------+----------------------+-----+-----+

| category_id | name | lft | rgt |

+-------------+----------------------+-----+-----+

| 1 | Electronice | 1 | 18 |

| 2 | Monitoare | 2 | 7 |

| 3 | CRT | 3 | 4 |

| 4 | LCD | 5 | 6 |

| 5 | Aparate foto | 8 | 17 |

| 6 | SLR | 9 | 14 |

| 7 | Digitale | 10 | 11 |

| 8 | Pe film | 12 | 13 |

| 9 | Compacte | 15 | 16 |

+-------------+----------------------+-----+-----+

Parcurgere MPTT Electronice Monitoare CRT LCD Aparate foto SLR Compacte Digitale Pe film 1 2 3 4 5 6 7 8 9 10 11 12 1314 15 1617 18

Parcurgere MPTT SELECT * FROM tree WHERE lft >= 2 AND rgt <= 7 ORDER BY lft SELECT * FROM tree WHERE lft <= 10 AND rgt >= 11 SELECT * FROM tree WHERE rgt = lft+1 AND lft > 8 AND rgt < 17 Electronice Monitoare CRT LCD Aparate foto SLR Compacte Digitale Pe film 1 2 3 4 5 6 7 8 9 10 11 12 1314 15 1617 18

SELECT * FROM tree WHERE lft >= 2 AND rgt <= 7 ORDER BY lft

SELECT * FROM tree WHERE lft <= 10 AND rgt >= 11

SELECT * FROM tree WHERE rgt = lft+1 AND lft > 8 AND rgt < 17

Inserare MPTT Electronice Monitoare CRT LCD Aparate foto SLR Compacte Digitale Pe film 1 2 3 4 5 6 7 8 9 10 11 12 1314 15 1617 18 Plasm ă

Inserare MPTT UPDATE tree SET rgt = rgt + 2 WHERE rgt > 6 UPDATE tree SET lft = lft + 2 WHERE lft > 6 INSERT INTO tree SET lft = 7, rgt = 8, name = “Plasm ă ” Electronice Monitoare CRT LCD Aparate foto SLR Compacte Digitale Pe film 1 2 3 4 5 6 7 8 9 101112 1 3 1 4 1 5 1 6 1 7 1 8 1 9 20 Plasm ă

UPDATE tree SET rgt = rgt + 2 WHERE rgt > 6

UPDATE tree SET lft = lft + 2 WHERE lft > 6

INSERT INTO tree SET lft = 7, rgt = 8, name = “Plasm ă ”

Ştergere MPTT Electronice Monitoare CRT LCD Aparate foto SLR Compacte Digitale Pe film 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Ştergere MPTT DELETE FROM tree WHERE lft >= 9 AND rgt <= 14 UPDATE tree SET rgt = rgt - 6 WHERE rgt > 14 UPDATE tree SET lft = lft - 6 WHERE lft > 14 Electronice Monitoare CRT LCD Aparate foto SLR Compacte Digitale Pe film 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

DELETE FROM tree WHERE lft >= 9 AND rgt <= 14

UPDATE tree SET rgt = rgt - 6 WHERE rgt > 14

UPDATE tree SET lft = lft - 6 WHERE lft > 14

Resurse adiţionale Managing Hierarchical Data in MySQL http://dev.mysql.com/tech-resources/articles/hierarchical-data.html Storing Hierarchical Data in a Database http://www.sitepoint.com/article/hierarchical-data-database Four ways to work with hierarchical data http://www.evolt.org/article/Four_ways_to_work_with_hierarchical_data/17/4047

Managing Hierarchical Data in MySQL

http://dev.mysql.com/tech-resources/articles/hierarchical-data.html

Storing Hierarchical Data in a Database

http://www.sitepoint.com/article/hierarchical-data-database

Four ways to work with hierarchical data

http://www.evolt.org/article/Four_ways_to_work_with_hierarchical_data/17/4047