10. Choosing Storage Structures and Secondary Indexes : Storage Structure Comparison Summary
 
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Storage Structure Comparison Summary
The following chart is a quick reference for deciding which storage structure to use.
Why a particular storage structure is good or bad for the condition listed is described under the section Storage Structures and Performance (see page Storage Structures and Performance). Information on secondary indexes is described in Secondary Indexes (see page Secondary Indexes).
Ratings in the following chart are as follows: 1‑Excellent, 2‑Good, 3‑OK, 4‑Bad, N/A-not applicable.
Requirement
Heap
Hash
ISAM
B-tree
Pattern matching
4
4
1
1
Range searches
4
4
1
1
Exact-match keyed retrievals
4
1
2
2
Sorted data (without sort-by)
4
4
2
1
Concurrent updates
4
1
1
2
Addition of data without needing to modify
2
3
3
1
Sequential addition of data (incremental key)
1*
2
4
1
Initial bulk copying of data
1
2
2
2
Table growth: none, static
N/A
1
1
2
Table growth: some, periodically plan to modify
N/A
1
1
2
Table growth: great deal -- too fast to modify
3
3
3
1
Table size: small (under 15 main pages)
2
1
1
3
Table size: medium (disk space available for any modify)
4
1
1
1
Frequent deletions
4
1
1
3
Frequent updates
4
1
1
2
Secondary index structure
N/A
1
1
1
* Refers to secondary indexes used with a heap table.