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Pemodelan Data (Data Modeling)

Pemodelan Data (Data Modeling). Data modeling – suatu teknik untuk mengorganisasi dan mendokemntasi data sistem . Disebut juga database modeling

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Pemodelan Data (Data Modeling)

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  1. Pemodelan Data (Data Modeling) Data modeling – suatu teknik untuk mengorganisasi dan mendokemntasi data sistem. Disebut juga database modeling Entity relationship diagram (ERD) – suatu modeldatayang menggunakan beberapa notasi untuk menggambarkan datadalam bentuk entitas danrelasi

  2. ContohEntity Relationship Diagram (ERD)

  3. Entitas suatuobjek yang dapatdiidentifikasidalamlingkunganpemakai, sesuatu yang pentingbagipemakaidalamkontekssistem yang akandibuat

  4. Entitas Entity instance entity instances

  5. Data Modeling Concepts: Attributes Atributmendekripsikankarakteristik (properti) darisuatuentitas Compound attribute – suatu atributyang terdiri dari beberapa atribut lain. Nama lain:concatenated attribute, composite attribute

  6. Key Key – satu atau lebit atribut memounyai nilai yang unik. Nama lain identifier.

  7. Relasi • Menunjukkanhubungan yang terjadidiantarasejumlahentitas yang berasaldarihimpunanentitas yang berbeda

  8. Kardinalitas Kardinalitasatauderajatrelasimenunjukkanjumlahminimum dan maksimumentitas yang dapatberelasidenganentitaspadahimpunanentitas yang lain bidirectional

  9. Notasi Kardinalitas

  10. N-ary relationships • Relasidaritigaentitasataulebih

  11. Entitas Asosiatif (Associative entity Associative entity – entitas yang atribut primary key diturunkan lebih dari 1 entitas lain (parents). Associative Entity

  12. Recursive Relationship Recursive relationship - Relasi yang terjadidarisebuahentitaskeentitas yang sama

  13. Foreign Key Foreign key – atribut yang merupakan atribut primary key pada entitas yang lain

  14. Foreign Keys Primary Key Primary Key Foreign Key Duplicated from primary key of Dorm entity (not unique in Student entity)

  15. Identifying Relationships Identifying relationship – relasi yang key dari parent entity juga merupakan bagian primary key darichild entity. • The child entity disebuta weak entity.

  16. Data Modeling Concepts: Sample CASE Tool Notations

  17. Nonspecific Relationships

  18. Resolving Nonspecific Relationships The verb or verb phrase of a many-to-many relationship sometimes suggests other entities.

  19. Resolving Nonspecific Relationships (continued) Many-to-many relationships can be resolved with an associative entity.

  20. Resolving Nonspecific Relationships (continued) Many-to-Many Relationship While the above relationship is a many-to-many, the many on the BANK ACCOUNT side is a known maximum of "2." This suggests that the relationship may actually represent multiple relationships... In this case two separate relationships.

  21. Generalisasi • Spesialisasi : pengelompokkansuatuentitasmenjadientitas-entitasbaru (prosestop-down) • Generalisasi : entitas-entitas yang mula-mulaterpisahkemudiandisatukanmenjadisatuentitas (prosesbottom-up)

  22. Hirarki Generalisasi

  23. The Context Data Model

  24. The Key-based Data Model

  25. The Key-based Data Model with Generalization

  26. The Fully-Attributed Data Model

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