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Number of relationship models
2022-07-04 10:13:00 【Wildcraner】
Calculation formula ： Number of relational patterns = Number of entity sets + The number of many to many connections
Example 1
As in this question , The number of entity sets is 3 individual , Many to many numbers are 2 individual , Then the number of relational patterns =5
Example 2
As in this question , The number of entity sets is 3 individual , Many to many numbers are 1 individual , Then the number of relational patterns =4
Example 3
As in this question , The number of entity sets is 4 individual , Many to many numbers are 2+1+2 individual , Then the number of relational patterns =9
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