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u |
Different
tables are related to one another with
|
|
primary
and foreign key matches.
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|
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n |
Ex.
Sales order table holds customer FK
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|
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u |
Relationships
may be:
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|
|
n |
(Zero
or) One-to-one
|
|
|
n |
(Zero
or) One-to-Many
|
|
|
|
n |
Self-join
|
|
|
u |
Relational
Integrity (RI) can be enforced with
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|
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triggers,
RI Builder, or code
|
|
|
n |
Ex.
Cannot delete invoice with detail items
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|