Exercises

1. Exercises • Apa saja komponen utama dari ER-Diagram ? • Yang membuat sebuah entity unik adalah… • Sebutkan tipe dari attribut berikut: • Nama anak • Jenis kelamin • Jumlah anak • Total discount • Harga buku • Pengarang buku • Apa yang dibutuhkan untuk membuat rancangan logical database (ER-Diagram) ? • Apakah yang dimaksud dengan weak entity ? • Bagaimana membentuk key attribut dari weak entity ? Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Revised by IB & SAM, Fasilkom UI, 2005

2. More Exercises… • In E-R modeling, entities within an entity class may have different attributes. [T/F] • In E-R modeling, an attribute may be either composite or multi-value, but it cannot be both. [T/F] • An identifier (key attribute) of an entity instance must consist of one and only one attribute. [T/F] • The degree of a relationship is expressed as the relationship’s maximum cardinality. [T/F] • Relationships among instances of a single entity class are called redundant relationships. [T/F] Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Revised by IB & SAM, Fasilkom UI, 2005

3. A Bank Enterprise Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Revised by IB & SAM, Fasilkom UI, 2005

4. Sebutkan (nonweak) entity pada ERD tsb! • Sebutkan (weak) entity pada ERD tsb jika ada! • Sebutkan relasi yg ada serta tentukan batasan (min,max) –nya! • Sebutkan user requirement yg melandasi ERD tsb! • Jika setiap customer harus punya satu account namun paling banyak dua pinjaman pada satu waktu dan setiap cabang tidak boleh punya lebih dari 1000 pinjaman. Bagaimana hal ini dibuat dgn notasi (min,max)? Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Revised by IB & SAM, Fasilkom UI, 2005

5. A university database contains information about professors (identified by social, security number, or SSN) and courses (identified by courseid). Professors teach courses; each of the following situations concerns the Teaches relationship set. For each situation, draw an ER diagram that describes it (assuming no further constraints hold). • Professors can teach the same course in several semesters, and each offering must be recorded. • Professors can teach the same course in several semesters, and only the most recent such offering needs to be recorded. (Assume this condition applies in all subsequent questions.) • Every professor must teach some course. • Every professor teaches exactly one course (no more, no less). • Every professor teaches exactly one course (no more, no less), and every course must be taught by some professor. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Revised by IB & SAM, Fasilkom UI, 2005

6. Develop ER-Diagram based on following facts ! • Manufacturers have a name, which we may assume is unique, an address, and a phone number • Product have a model number and a type (e.g., television set). Each product is madeby one manufacturer, and different manufacturers may have different products withthe same model number. However, you may assume that no manufacturer would havetwo products with the same model number. • Customers are identified by their unique social security number. They have emailaddresses, and physical addresses. Several customers may live at the same (physical)address, but we assume that no two customers have the same email address. • An order has a unique order number, and a date. An order is placed by one customer.For each order, there are one or more products ordered, and there is a quantity foreach product on the order. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Revised by IB & SAM, Fasilkom UI, 2005