Matakuliah
Tahun
Versi
: <<M0264>>/<<Sistem Manajemen Basis Data>>
: <<2006>>
: <<1/1>>
Pertemuan <<11>>
Desain fisik basis data
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Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Mahasiswa dapat mendesain fisik basis
data
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Outline Materi
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Pengenalan Desain Fisik Basis Data
Petunjuk Pemilihan Index
Contoh Sederhana Pemilihan Index
Ikhtisar Basis Data Tuning
Pemilihan Skema Konseptual
Pemilihan Queries dan Views
DBMS Benchmarking
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PENGENALAN DISAIN FISIK BASIS DATA
• Database Workloads
• Physical Design and Tuning Decisions
• Need for database tuning
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PETUNJUK PEMILIHAN INDEX
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Guideline 1
Guideline 2
Guideline 3
Guideline 4
Guideline 5
Guideline 6
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CONTOH SEDERHANA PEMILIHAN INDEX
SELECT E.ename, D.mgr
FROM Emp E, Dept D
WHERE D.dname=‘Toy’ AND E.dno=D.dno
SELECT E.ename, D.mgr
FROM Emp E, Dept D
WHERE E.sal BETWEEN 10000 AND 20000
AND E.hobby=‘Stamps’ AND E.dno=D.dno
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IKHTISAR BASIS DATA TUNING
• Tuning indexes
• Tuning the conceptual schema
• Tuning queries and views
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PEMILIHAN SKEMA KONSEPTUAL
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Settling for a weaker normal form
Denormalization
Choice of composition
Vertical partitioning of BCNF Relations
Horizontal Decomposition
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PEMILIHAN QUERIES DAN VIEWS
• Contoh :
CREATE ASSERTION CheckDep
CHECK ( NOT EXISTS ( SELECT *
FROM PartInfo P, ContractInfo C
WHERE P.sid=C.sid AND P.did=C.did
GROUP BY C.jid, P.pid
HAVING COUNT (C.cid) > 1 ))
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PEMILIHAN QUERIES DAN VIEWS
• If a query runs slower than expected, check if an
index needs to be re-built, or if statistics are too
old.
• Sometimes, the DBMS may not be executing the
plan you had in mind. Common areas of
weakness:
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Selections involving null values.
Selections involving arithmetic or string expressions.
Selections involving OR conditions.
Lack of evaluation features like index-only strategies
or certain join methods or poor size estimation.
• Check the plan that is being used! Then adjust
the choice of indexes or rewrite the query/view
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DBMS BENCHMARKING
• Online Transaction Processing
Benchmarking
• Query Benchmarking
• Menggunakan Benchmarking
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<< PENUTUP>>
Dilanjutkan ke pert. 12
Paralel dan Basis Data Terdistribusi
12