Download - Marathon class psbd
MARATHON CLASSEdi Purnomo PutraLecture Code : D5386
Normalisasi• Tujuan Normalisasi• Update anomalisinsert, update, delete• Functional dependency• Full functional dependency
nilainim, KdMtk• Partial dependency
namabarangidbarang
Normalisasinormalisasi 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
Tujuan Normalisasi1) 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
Datawarehouse• Karakteristik DWH• ETL(Extract, transform, loading)• Datamart vs DWH
Karakteristik • Subject oriented
Customer, product, sales• Integrated
Data konsistenMale, M, Ma Male
• NonvolatileTidak bisa diubah refresh scd(Slow Changing Dimension)
• Time variantMingguna, bulanan, tahunandimensi waktu
ETL • Extract
Ekstract data dari ODS /OLTP(OPERASIONAL DATA SOURCE)• Transform
Penyamaan data JL, jalan, JLN JLMelakukan kalkulasi aggregate
• LoadMasukan data ke DWH/Data Mart
Datamart VS DWH• Data mart• 1 subject• Bagian dari data warehouse• Relative Sebentar• DWH• Beberapa subject• Implementasi waktu lama
ER• Fan trap• Chasm trap• Participant disjoint• Strong entity • Weak entity• Degree relation• Recursive• Single value atribute• Multivalue attribute
Prticiapant Disjoint• ParticipantAnd / or• Join disjoin Optional and mandatory
Participant Disjoint
Participant Disjoint
Optional OR
Mandatory Or
Degree
Degree of a RelationshipNumber of participating entities in relationship.
Relationship of degree :two is binary three is ternaryfour is quaternary.
Binary relationship called POwns
Ternary relationship called Registers
Quaternary relationship called Arranges
Recursive relationship called Supervises with role names
Attributes
• Attribute– Property of an entity or a relationship type.
• Attribute Domain– Set of allowable values for one or more
attributes.
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.
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.
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.
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.
• 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
An Example of a Fan Trap
Semantic Net of ER Model with Fan Trap
• At which branch office does staff number SG37 work?
Restructuring ER model to remove Fan Trap
Semantic Net of Restructured ER Model with Fan Trap Removed
• SG37 works at branch B003.
An Example of a Chasm Trap
Semantic Net of ER Model with Chasm Trap
• At which branch office is property PA14 available? Mengawasi, mengatur
ER Model restructured to remove Chasm Trap
Semantic Net of Restructured ER Model with Chasm Trap Removed
Key Type• Primary key NIM, KDMataKuliah• Composite key KdMatakuliah+NIM• Foreign key • Candidate key• Alternate key
Aggregate• Sum• Avg• Min• Max• Count
Intersect, except,union