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We are following that for consistency  \n1 N  \n (1, N)   (1,1)   \n[http://www.vertabelo.com/blog/technical-articles/chen-erd-notation](http://www.vertabelo.com/blog/technical-articles/chen-erd-notation)[ ](http://www.vertabelo.com/blog/technical-articles/chen-erd-notation)[http://www.vertabelo.com/blog/technical-articles/crow-s-foot-notation](http://www.vertabelo.com/blog/technical-articles/crow-s-foot-notation)  \n[https://creately.com/](https://creately.com/)  \n[https://www.draw.io/](https://www.draw.io/)  \nCSC 261, Spring 2017, UR  \nSpecial Symbols Used  \nCSC 261, Spring 2017, UR  \nStrong and Weak Entities  \n• A weak entity is an entity whose instances cannot exist in the database without the existence of an instance of another entity  \n• Any entity that is not weak entity is called a strong entity  \n– Instances of a strong entity can exist in the database independently  \n• The weak entity’s identifier is a combination of the identifier of the owner entity and the partial key of the weak entity.  \nCSC 261, Spring 2017, UR  \nIn E/R Diagrams  \nname  \n| \u003Cbr>Players |  |\n| --- | --- |\n|  |  |\n\n• Double diamond for supporting many-one relationship.  \n• Double rectangle for the weak entity set.  \nExample: Weak Entity Set  \n• name is almost a key for football players, but there might be two with the same name.  \n• number is certainly not a key, since players on two teams could have the same number.  \n• But number, together with the team name related to the player should be unique.  \nPartial vs Total Participation  \n• An entity set may participate in a relation either totally or partially.  \n• Total participation means that every entity in the set is involved in the relationship  \n– depicted as a double line.  \n• Partial participation means that not all entities in the set are involved in the relationship, e.g. , not every professor guides a student  \n– depicted by a single line.  \nCSC 261, Spring 2017, UR  \nWeak Entity , Total Participation and Partial Key  \nCSC 261, Spring 2017, UR","cbCaiuAL0vVmirhn","https://ap.wps.com/l/cbCaiuAL0vVmirhn","pdf",28770602,47,"English","# ER model and agenda\n## Chen vs Crow’s Foot notation\n## Special symbols and entity types\n# Strong vs weak entities\n## Weak entity identifier and partial key\n# Participation in relations\n## Partial vs total participation","[{\"question\":\"What is the difference between Chen notation and Crow’s Foot notation in ER diagrams?\",\"answer\":\"The lecture contrasts Chen notation with Crow’s Foot notation and follows a specific (min, max) convention for consistency, referencing external notation resources.\"},{\"question\":\"What defines a weak entity and how is it identified?\",\"answer\":\"A weak entity cannot exist in the database without an instance of the owner entity. Its identifier combines the owner entity’s identifier with the weak entity’s partial key.\"},{\"question\":\"How do partial and total participation differ in ER diagrams?\",\"answer\":\"Total participation means every entity in the set participates in the relationship and is depicted with a double line. Partial participation means not all entities participate and is depicted with a single line.\"}]","CSC 261/461 - Database Lecture (Fall 2017) - ER Model and Entities | PDF",1792966240,118]