Example 1. Non-Dense (Primary) Index,

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Example 1. Non-Dense (Primary) Index, ONE FREE
matches file ordering
Records
Index
111 121 1112 111 131 2143 121 234 4544 121 349
6341 235 121 2311 235 122 4993 266 333
4343
111 121 1113 235 121 2311 266 333 4343
block
block
Search for 235 122 4993
block
2
Example 2. (Clustered) Non-Dense Index (ONE
FREEmatches file ordering)
Records
Index
Blue 2 Blue 3 Blue 9 Green 1 Green 2 Green 6 Grey
1 Red 1 Red 9 Red 10 Yellow 6
Blue Green Grey Red Yellow
block
block
block
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Example 3. Secondary (Dense) Index 1 entry per
record
Records
Index

• Blue
• Yellow
• Green
• Yellow
• Blue
• Yellow
• Green
• Green
• 43 Blue

Blue Blue Blue Green Green Green Yellow Yellow Yel
low
4
Example 4. Secondary (Dense) Index 1 entry per
value, all addresses
Records
Index

• Blue
• Yellow
• Green
• Yellow
• Blue
• Yellow
• Green
• Green
• 43 Blue

Blue Green Yellow
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Example 5. Secondary (Dense) Index 1 entry per
value, address to addresses
Records
Index
Addresses

• Blue
• Yellow
• Green
• Yellow
• Blue
• Yellow
• Green
• Green
• 43 Blue

Blue Green Yellow
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Example 6. Multilevel Index
First Level
Second Level
Records
1 3 4 15 23 24 25 39 42 52 53
1 15 25 39 52
1 25 52
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Example 7a. B Tree Node Structure
p1 v1 p2 v2 p3 v3 p4 v4 p5
Node 1
Node 2
Node 3
Node 4
Node 5
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Example 7b. B Tree Node Structure
p1 15 p2 30 p3 50 p4 93 p5
31 33 47 50
94 99 103
1 12 15
16 21 24 30
51 56 78 81 93
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HashingFunction(value) location (i.e. bin)

• Example Mod 13 of (SSN)
• 123-45-6789 mod 13 1
• 234-56-7899 mod 13 7
• 864-93-5196 mod 13 8
• 963-77-5936 mod 13 6
• 058-32-9744 mod 13 5
• 532-87-1523 mod 13 2
• 274-98-6648 mod 13 1

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• Bin 1
• 123-45-6789 mod 13 1
• 274-98-6648 mod 13 1
• Bin 2
• 532-87-1523 mod 13 2
• Bin 3
• Bin 4
• Bin 5
• 058-32-9744 mod 13 5
• Bin 6
• 963-77-5936 mod 13 6
• Bin 7
• 234-56-7899 mod 13 7
• Bin 8
• 864-93-5196 mod 13 8
• . (plus overflow Bin)

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Indexing Organization Options
File (on Disk) Index in RAM
Unordered
Ordered No Index
Ordered One Free Primary Non-Dense Index (BTree) and possibly Multiple (costly) Secondary Dense Indexes (BTree)
Hash No physical index