Back to IF3140 Sistem Basis Data
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1. B+-tree
Diagram:
+----------+
| 11, 19 |
+----------+
|
+------------+--------------+
| | |
+---+---+ +--+--+ +--+--+--+--+
|2,3,5,7|---->|11,17|---->|19,23,29,31|
+-------+ +-----+ +-----------+
2. Hash Index
Aturan:
-
Fungsi hash:
h(x) = x mod 8. -
Kapasitas bucket: 3 record.
Proses Perhitungan Hash:
h(17) = 17 mod 8 = 1h(3) = 3 mod 8 = 3h(2) = 2 mod 8 = 2h(11) = 11 mod 8 = 3h(19) = 19 mod 8 = 3h(7) = 7 mod 8 = 7h(29) = 29 mod 8 = 5h(23) = 23 mod 8 = 7h(31) = 31 mod 8 = 7h(5) = 5 mod 8 = 5
Diagram:
Hash Value Bucket
+----------+ +----------------+
| 0 | -> | |
+----------+ +----------------+
| 1 | -> | 17 |
+----------+ +----------------+
| 2 | -> | 2 |
+----------+ +----------------+
| 3 | -> | 3, 11, 19 | <-- Penuh
+----------+ +----------------+
| 4 | -> | |
+----------+ +----------------+
| 5 | -> | 29, 5 |
+----------+ +----------------+
| 6 | -> | |
+----------+ +----------------+
| 7 | -> | 7, 23, 31 | <-- Penuh
+----------+ +----------------+
Penjelasan Diagram Hash:
-
Setiap nilai
search-keydihitung nilai hash-nya menggunakanmod 8. -
Hasil hash (0 sampai 7) menentukan ke bucket mana data tersebut akan disimpan.
-
Setiap bucket dapat menampung hingga 3 record. Berdasarkan data yang ada, bucket untuk hash value
3dan7terisi penuh.