Back to IF3140 Sistem Basis Data 94/100

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 = 1
  • h(3) = 3 mod 8 = 3
  • h(2) = 2 mod 8 = 2
  • h(11) = 11 mod 8 = 3
  • h(19) = 19 mod 8 = 3
  • h(7) = 7 mod 8 = 7
  • h(29) = 29 mod 8 = 5
  • h(23) = 23 mod 8 = 7
  • h(31) = 31 mod 8 = 7
  • h(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-key dihitung nilai hash-nya menggunakan mod 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 3 dan 7 terisi penuh.