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Slide4 er-stu
The document discusses different types of relationships in entity-relationship (ER) modeling including unary, binary, ternary, and n-ary relationships. It provides examples of one-to-one (1:1), one-to-many (1:M), and many-to-many (M:N) relationships between entities. It also covers ER diagram concepts such as entities, attributes, keys, and the use of primary and foreign keys to link entities.
Slide4 er-stu
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- 7. (Connectivity) - - 1:1 - - 1:M - - M:N
- 8. Entity A Entity B Entity Entity 1 1
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- 10. One-to- Many Relationship) Entity A Entity B Entity Entity
- 11. - - M
- 12. Many-to- Many Relationship) Entity A EntityB Entity Entity
- 13. - - M N
- 14. 1 M
- 15. M N
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- 18. EX 1 M 0, 3 (1, 1)
- 19. EX 1 1, 2, 3, 4, 5 6 1 40
- 20. Regular Entity name Entity Weak Entity
- 21. Regular Entity Strong Entity Identity ------------------------------------------------ ------------------------------------ Weak Entity Parent Entity Parent Entity
- 22. Identity Identity -
- 23. Employee EmpID Name Sex Saraly 001 M 8,500 002 M 9,000 Time_in_out 003 F 12,000 EmpID Date Time_in Time_o ut 001 15/2/52 7.30 17.30 002 15/2/52 8.00 18.00 003 15/2/52 7.45 17.45 001 16/2/52 8.00 18.00 002 16/2/52 7.30 17.00 003 16/2/52 8.00 17.30
- 24. Student Subject (Strong) (Strong) 45001 01 02 45002 Regis_Det ail(Weak) 450 1/45 01 01 450 1/45 01 02 450 1/45 02 01
- 26. Composite Composite Entity Entity Entity Entity Many to Many Key Attribute Composite Entity M N Key Attribute Entity M:M 1:M 1 M M 1
- 27. : - - - ER
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- 30. ER 1:1 ER
- 31. ER 1:1 ( ) primary key : pk) foreign key : fk)
- 32. ER 1:M ER Diagram M ER M primary key: pk) M foreign key : fk) M
- 33. ER 1:M( )
- 34. ER M:N ER Diagram M: N
- 35. ER M:N ( ) ER Diagram M:N
- 36. M:N M 1:M N ER 1:M 1 M M 1
- 37. E-R Diagram 1. 2. 3. 4. 5.
- 38. (Attribute) Domain
- 39. RelationCardinality = PERSONS Name Addres Phone s Manee Phitsanulo 1111111 k Tuple John Chaingmai 2222222 Peter Bangkok 3333333 Tata Tak 4444444 Degree = Attribute
- 40. Domain Attribute salary integer 8 digits Data Type Emp_name Format chars string 15 sex string M,F
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