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# Entity Relationship Diagram presentation

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### Entity Relationship Diagram presentation

1. 1. ROYAL UNIVERSITY OF PHNOM PENH Depart : Computer Science Subject : Software Engineering Class : E2, Year4 Batch : 13 Lecturer : KEAN TAK Pre Topic : Entity Relationship and Diagram Group1 1. Ben Piseth 7. Chea Sokhom 2. Chan Kimchhun 8. Chea Sakall 3. Chan Sopov 9. Chin puttra 4. Chanthy Raksmey 10.Chhim Vichhai 5. Chao Yokchivve 11.Choun Piseth 7. Chev Toun 1
2. 2. Group 1 WHAT IS ERD?• Is a diagram used to conduct data modeling activity.• It describes the relationship between data object.• DBA and System Analyst used ERD to perform data modeling, and explain the diagram to stakeholders. 2
3. 3. Group 1 ERD COMPONENTS• The primary components of ERD are: • Data object • Attribute • Relationship 3
4. 4. Group 1 ERD COMPONENTS Association between the instances of one or more entity types Data Object Relationship AttributesPerson, place, object, event named property oror concept about which data characteristic of anis to be maintained entityRepresents a set or collection ofobjects in the real world thatshare the same properties 4
5. 5. Group 1 CARDINALITY• express the minimum and maximum number of occurrences of one entity for a single occurrence of the other • One-to-One (1:1) • One-to-many (1:N) • Many-to-Many (M:N) 5
6. 6. Group 1RELATIONSHIP CARDINALITYGraphic Cardinality Exactly 1 0 or 1 1 or more 0 or many More than 1 6
7. 7. Group 1 DEGREE OF RELATIONSHIP• Refer to the number of Entity type that participate in the relationship.• There are three case: • Unary: between two instances of one entity type • Binary: between the instances of two entity types • Ternary: among the instances of three entity types 7
8. 8. Group 1EXAMPLE OF ERD 8
9. 9. Group 1 BENEFIT OF ERD• Visual representation :• Effective communication• Simple to understand• High flexibility 9
10. 10. Group 1, Section 4.4THE END Thanks for your enjoying. Good Luck !!! 10