3. Normalisasi
normalisasi adalah suatu teknik Formal Dalam Menentukan
atribut dan menghasilkan kumpulan relasi yang bertujuan
untuk menyediakan kebutuhan data yang diperlukan oleh
perusahaan
• A technique for producting a set of relation with desirable
properties, given data reqruirements of an enterprise
4. Tujuan Normalisasi
1) Menjamin struktur data yang konsisten.
2) Kerangkapan data yang minimal.
3) Stabilitas struktur data yang maksimal
1) Meminimalkan Jumlah Kapasitas Penyimpanan
Yang Diperlukan Untuk menyimpan data.
2) Meminimalkan resiko data yang tidak konsisten
dalam suatu basis data.
3) Meminimalkan
kemungkinan update dan delete anomaly.
4) Memaksimalkan stabilitas dari struktur data
Manfaat Normalisasi
8. Karakteristik
• Subject oriented
Customer, product, sales
• Integrated
Data konsisten
Male, M, Ma Male
• Nonvolatile
Tidak bisa diubah refresh scd(Slow Changing Dimension)
• Time variant
Mingguna, bulanan, tahunandimensi waktu
9. ETL
• Extract
Ekstract data dari ODS /OLTP(OPERASIONAL DATA SOURCE)
• Transform
Penyamaan data JL, jalan, JLN JL
Melakukan kalkulasi aggregate
• Load
Masukan data ke DWH/Data Mart
10. Datamart VS DWH
• Data mart
• 1 subject
• Bagian dari data warehouse
• Relative Sebentar
• DWH
• Beberapa subject
• Implementasi waktu lama
11. ER
• Fan trap
• Chasm trap
• Participant disjoint
• Strong entity
• Weak entity
• Degree relation
• Recursive
• Single value atribute
• Multivalue attribute
17. Degree
Degree of a Relationship
Number of participating entities in
relationship.
Relationship of degree :
two is binary
three is ternary
four is quaternary.
22. Attributes
• Attribute
– Property of an entity or a relationship type.
• Attribute Domain
– Set of allowable values for one or more
attributes.
23. Attributes
• Simple Attribute
– Attribute composed of a single component
with an independent existence.
• Composite Attribute
– Attribute composed of multiple components,
each with an independent existence.
24. Attributes
• Single-valued Attribute
– Attribute that holds a single value for each
occurrence of an entity type.
• Multi-valued Attribute
– Attribute that holds multiple values for each
occurrence of an entity type.
25. Attributes
• Derived Attribute
– Attribute that represents a value that is
derivable from value of a related attribute,
or set of attributes, not necessarily in the
same entity type.
26. Entity Type
• Strong Entity Type
– Entity type that is not existence-dependent
on some other entity type.
• Weak Entity Type
– Entity type that is existence-dependent on
some other entity type.
27. • Fan Trap
– Where a model represents a relationship
between entity types, but pathway between
certain entity occurrences is ambiguous.
• Chasm Trap
– Where a model suggests the existence of a
relationship between entity types, but pathway
does not exist between certain entity
occurrences.
Trap