Relationship in database lecture with English language and Persian Translation. This lecture is for absolutely beginners. This is the fifth lecture in database one.

1. Relationship
‫ارتباط‬
‫کننده‬ ‫تهیه‬:‫عادل‬ ‫هللا‬ ‫عصمت‬

2. Topics:
• Relationship
• Degree of a relation
• Associative entity
• Cardinality of relationships
•‫ارتباط‬
•‫ارتباط‬ ‫درجه‬
•‫پذیر‬ ‫شرکت‬ ‫موجودیت‬
•‫ارتباط‬ ‫کاردینالیتی‬
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3. Relationship:
• Showing association among
two or more than two entity
types is called Relationship.
•‫اضا‬ ‫یا‬ ‫و‬ ‫دو‬ ‫بین‬ ‫رابطه‬ ‫دادن‬ ‫نشان‬‫فه‬
‫بنام‬ ‫را‬ ‫موجودیت‬ ‫نوع‬ ‫دو‬ ‫از‬ ‫تر‬
‫میکند‬ ‫یاد‬ ‫ارتباط‬.
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4. Continue…
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Teacher SubjectTeaches

5. Degree of a relation:
• The number of entity types
that participate in a
relationship is called its
degree.
•‫یک‬ ‫در‬ ‫که‬ ‫موجودیت‬ ‫نوع‬ ‫تعداد‬
‫درجه‬ ‫بنام‬ ‫میکند‬ ‫شرکت‬ ‫ارتباط‬
‫میشود‬ ‫یاد‬ ‫ارتباط‬.
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6. Degree of a relation…
• Three most common degree
are:
1. Unary Relationship(Degree
one).
2. Binary Relationship(Degree
two).
3. Ternary
Relationship(degree three).
•‫ذیل‬ ‫قرار‬ ‫معمول‬ ‫بسیار‬ ‫درجه‬ ‫سه‬
‫است‬:
.1‫یگانه‬ ‫ارتباط‬(‫یک‬ ‫درجه‬)
.2‫دوگانه‬ ‫ارتباط‬(‫دو‬ ‫درجه‬)
.3‫گانه‬ ‫سه‬ ‫ارتباط‬(‫سه‬ ‫درجه‬)
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7. Unary relationship(degree one):
• A relation between the
instances of single entity
type is called Unary(Degree
one) Relationship .
• An entity type linked with
itself, also called recursive
relationship.
•‫ن‬ ‫یک‬ ‫های‬ ‫نمونه‬ ‫بین‬ ‫ارتباط‬ ‫یک‬‫وع‬
‫یاد‬ ‫یگانه‬ ‫ارتباط‬ ‫بنام‬ ‫موجودیت‬
‫میشود‬.
•‫موجودیت‬ ‫نوع‬ ‫یک‬‫خودش‬ ‫با‬ ‫ایکه‬
‫ارتباط‬ ‫بنام‬ ‫همچنان‬ ‫باشد‬ ‫وصل‬
‫میشود‬ ‫یاد‬ ‫بازگشتی‬.
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person
Is_married_to
EMPLOYEE
Manages

8. Binary relationship(degree two):
• A relation between the
instances of two entity
types is called
binary(degree two)
relationship.
•‫های‬ ‫نمونه‬ ‫بین‬ ‫ارتباط‬ ‫یک‬‫نوع‬ ‫دو‬
‫ارتباط‬ ‫بنام‬ ‫موجودیت‬‫یاد‬ ‫دوگانه‬
‫میشود‬.
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9. Ternary relationship(degree three):
• A Relationship between the
instances of three entity
types is called
Ternary(Degree three)
relationship.
• Example: Many venders
ships many items to
many warehouses.
•‫های‬ ‫نمونه‬ ‫بین‬ ‫ارتباط‬ ‫یک‬‫سه‬‫نو‬‫ع‬
‫ارتباط‬ ‫بنام‬ ‫موجودیت‬‫ی‬ ‫گانه‬ ‫سه‬‫اد‬
‫میشود‬.
•‫مثال‬:‫اشیای‬ ‫زیاد‬ ‫گان‬ ‫فروشنده‬
‫انتقال‬ ‫زیاد‬ ‫های‬ ‫گدام‬ ‫به‬ ‫را‬ ‫زیادی‬
‫میدهد‬.
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10. Ternary relationship(degree three)…
• The Institute might need to
record which teachers
taught which subjects in
which courses.
•‫داشت‬ ‫ضرورت‬ ‫ممکن‬ ‫انستیتیوت‬‫ه‬
‫استا‬ ‫کدام‬ ‫که‬ ‫کند‬ ‫ثبت‬ ‫تا‬ ‫باشد‬‫کدام‬ ‫د‬
‫درس‬ ‫صنف‬ ‫کدام‬ ‫در‬ ‫را‬ ‫مضمون‬
‫میدهد‬.
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11. Degree of relationships:
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Entities of
two different
types related
to each other.
Entities of three
different types
related to each
other.
One entity
related to
another of
the same
entity type.

12. Associative entity:
• The presence of one or
more attributes on a
relationship suggests to the
designer that the
relationship should perhaps
be represented as an entity
type.
• That entity type is called
associative Entity.
•‫یک‬ ‫از‬ ‫بیشتر‬ ‫یا‬ ‫و‬ ‫یک‬ ‫موجودیت‬
‫ب‬ ‫ارتباط‬ ‫یک‬ ‫باالی‬ ‫خاصه‬ ‫صفت‬‫ه‬
‫ارت‬ ‫که‬ ‫میکند‬ ‫پیشنهاد‬ ‫دیزاینر‬‫به‬ ‫باط‬
‫داده‬ ‫نمایش‬ ‫موجودیت‬ ‫نوع‬ ‫شکل‬
‫شود‬.
•‫بنام‬ ‫موجودیت‬ ‫نوع‬ ‫این‬ ‫که‬
‫میشود‬ ‫یاد‬ ‫پذیر‬ ‫شرکت‬ ‫موجودیت‬.
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13. Associative entity example:
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STUDENT COURSE
Std_id S_name Course_id C_title
Certificate
Date_comp
Certificate_No

14. Cardinality of relationships:
• One to One:
• Each entity in the
relationship will have
exactly one related entity.
• For example:
•‫یک‬ ‫به‬ ‫یک‬:
•‫یک‬ ً‫ا‬‫دقیق‬ ‫ارتباط‬ ‫در‬ ‫موجودیت‬ ‫هر‬
‫داشت‬ ‫خواهد‬ ‫وابسته‬ ‫موجودیت‬.
•‫مثال‬ ‫بطور‬:
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Person Passporthas

15. Cardinality of relationships…
• One to Many:
• An entity on one side of the
relationship can have many
related entities, but an
entity on the other side will
have a maximum of one
related entity.
• For example:
•‫چند‬ ‫به‬ ‫یک‬:
•‫ارتباط‬ ‫طرف‬ ‫یک‬ ‫در‬ ‫موجودیت‬ ‫یک‬
‫وابس‬ ‫موجودیت‬ ‫چندین‬ ‫که‬ ‫میتواند‬‫ته‬
‫طرف‬ ‫موجودیت‬ ‫اما‬ ‫باشد‬ ‫داشته‬ ‫را‬
‫وابس‬ ‫موجودیت‬ ‫یک‬ ‫حداکثر‬ ‫دیگر‬‫ته‬
‫داشت‬ ‫خواهد‬.
•‫مثال‬ ‫بطور‬:
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Instructor Coursesteaches

16. Cardinality of relationships…
• Many to Many:
• Entities on both sides of the
relationship can have many
related entities on the other
side.
•‫چند‬ ‫به‬ ‫چند‬:
•‫طرف‬ ‫دو‬ ‫هر‬ ‫در‬ ‫ها‬ ‫موجودیت‬
‫موجودی‬ ‫چندین‬ ‫که‬ ‫میتواند‬ ‫ارتباط‬‫ت‬
‫باش‬ ‫داشته‬ ‫دیگر‬ ‫طرف‬ ‫در‬ ‫وابسته‬‫د‬.
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Student CoursesRegister for

17. Mandatory/Optional Relationships:
• Participation by an entity in
a relationship may
be optional or mandatory.
• For example:
•‫یک‬ ‫در‬ ‫موجودیت‬ ‫یک‬ ‫شرکت‬
‫اجباری‬ ‫یا‬ ‫و‬ ‫اختیاری‬ ‫ممکن‬ ‫رابطه‬
‫باشد‬.
•‫مثال‬ ‫بطور‬:
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Employee CarDrives

18. Continue…
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19. Continue…
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20. 1:50 AM
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