Principles Graphical Languages Modeling Constraints Conceptual Data Model Principles Graphical Languages Modeling Constraints Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Principles Main approach – object-oriented Class (entity set, object) Association (relationship, relation) Data member (attribute, property) Instance (entity, occurrence) Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Languages Entity Relationship model (E-R) (ERM) Entity set Relationship Attribute Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Languages MERISE Object with occurrences Relation Propertiy Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Languages Object Role Modeling (ORM)                             Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Languages Class Diagram Class with instances Association Property Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Conceptual Model Goals Starting from the dictionary and the rules this model tries to reveal the relations among the data and their interaction Example – School Rules Every class has a one and only one room. Every subject is teaches by only one teacher. Every class is taught a subject a fixed number of hours. Every student can have no more one mark in every subject. The school manages the timetable and the rating of students and teachers.. Dictionary Student’s Address, Subject, Number of Hours, Class Name, Student's Family Name, Teacher‘s Name, Mark, Room Number, Student’s Name Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Concepts Class (Entity class, Entity instance) Association Relationship between entity instances Attribute Properties Bogdan Shishedjiev Conceptual Data Model

Defining an Entity Class Give it a name (a noun) Define its attributes Define the rules What belongs to the class? How the instances are identified in the class? Identifying an instance (Identifier) First Name Last Name Address STUDENT Attribute NAME Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Association Give a name (a verb) Determine the participating classes Define the cardinalities Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Examples Bogdan Shishedjiev Conceptual Data Model

Identifier of an Association Bogdan Shishedjiev Conceptual Data Model

Cardinalities of an Association Cardinalities One to One 0..1 – 0..1 – Every student can use one locker 0..1 – 1 1 – 1 Every student uses a locker and ther are no free lockers Bogdan Shishedjiev Conceptual Data Model

Cardinalities of an Association Cardinalities One to Many 1 – 1..N 0..1 – 1..N 1 – 0..N 0..1 – 0..N Bogdan Shishedjiev Conceptual Data Model

Cardinalities of an Association Cardinalities Many to Many 1..N – 1..N 0..N – 1..N 0..N – 0..N Bogdan Shishedjiev Conceptual Data Model

Cardinalities of an Association Generalization Minimal cardinality Mandatory participation of every instance - 1 Optionally participation of every instance - 0 Maximal cardinality To only one instance of the other class – 1 To multiple instances of the other class - N Bogdan Shishedjiev Conceptual Data Model

Dimension of an Association Number of different classes participating in it Multidimensional Bogdan Shishedjiev Conceptual Data Model

Dimension of an Association Multidimensional Bogdan Shishedjiev Conceptual Data Model

Dimension of an Association One-dimensional (Reflexive) Bogdan Shishedjiev Conceptual Data Model

Aggregate Associations Aggregation Composition Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Weak Entities It is identified through the association Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Recommendations Don’t use high dimension associations Be aware not replace classes by associations Bogdan Shishedjiev Conceptual Data Model

Case Study – Management Rules A patient is characterized by: Unique Number Name address Phone Number General practitioner is characterized by: Serial Number Each patient is supervised by a GP A policlinic is characterized by: Address A specialist is characterized by: Each specialist has one or more specialties Each specialist can give consultations in one or more policlinics Each policlinic groups several specialists A patient can make an appointment for a consultation with specialist in a given policlinic, The specialist must work in this policlinic The appointment is for a date that is later than the date of appointment If the consultation does not take place a new appointment must be made no matter what are reasons for the failure Lists of appointment for every specialist are made at the beginning of the day. In the end of every day two reports are made: A log of appointment made A log of consultations done Bogdan Shishedjiev Conceptual Data Model

Case Study - Policlinic Bogdan Shishedjiev Conceptual Data Model

Case Study - Policlinic Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Subtypes Example – Hardware components order Bogdan Shishedjiev Conceptual Data Model

Bogdan Shishedjiev Conceptual Data Model Subtypes Bogdan Shishedjiev Conceptual Data Model