CHAPTER 4 The Mapping of E-R Model into Relational Model

CHAPTER 4 The Mapping of E-R Model into Relational Model

1. 2.0 Entity Mapping

   • 2 Sections
     • Strong Entity Mapping
       • the attributes of the relation are listed in round bracket () seperated by a comma ","
       • primary key attributes is placed as the first attribute followed by the non-attribute. "underlined" ayat yg PK tu
       • Derived Attribute
         • kotak dia tu buat garisan putus putus
         • kewujudan dia tu kita tk buat. dia automatic
       • Primary Key Attribute
         • underline ayat dia. kotak garis macam biasa
         • dgn kehadiran kunci PK drpd table lain
       • Foreign Key Attribute
         • duduk dalam entity yg many
       • Composite Attribute
         • ayat dia bubuh dalam bracket
       • Multi-valued Attribute
     • Weak Entity Mapping
       • whose existence is dependent on some other entity
       • dia ada PK, maka dia amik drpd strong entity

2. 3.0 Binary Relationship Mapping

   • melibatkan relationship antara 2 entity
     • x semestinya ada 1 relationship shj. tgk cardinality (1:1) (1:M). kita boleh tmbah relationship berdsrkan role dia.
   • 3 types
     • (1:1) Binary Relationship
     • (1:M) Binary Relationship
       • Manadatory Particpitaing Class
       • Optional Participating Class
     • (M:N) Binary Relationship

3. 4.0 Recursive Relationship Mapping

   • (1:M) Recursive Relationship Mapping
   • (M:N) Recursive Relationship Mapping

4. 5.0 Ternary Relationship Mapping

   • 1 relationship ada 3 entity

5. 6.0 Superclass and Subclass Mapping

   • subclass ada special attribute