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So, in your example, during the design of the database, the reason I must understand that the weak entity is the child and the strong entity is the parent is because ... that informs me of how to depict the relationship properly in the ERD so that the eventual database &quot;can handle any kind of query&quot;?<br />
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What do you mean by &quot;It should no be depend on any case&quot;?
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So, in your example, during the design of the database, the reason I must understand that the weak entity is the child and the strong entity is the parent is because ... that informs me of how to depict the relationship properly in the ERD so that the eventual database "can handle any kind of query"?

What do you mean by "It should no be depend on any case"?

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I know WHAT these concepts are; I understand their definitions: &nbsp;strong/weak entity, strong/weak relationship, participant optionality. &nbsp;I do not understand WHY they are important to database design. &nbsp;Why do I care if an entity is strong or weak? &nbsp;Why do I care if a relationship is strong or weak? &nbsp;Why do I care if participant optionality is optional or mandatory?
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I know WHAT these concepts are; I understand their definitions:  strong/weak entity, strong/weak relationship, participant optionality.  I do not understand WHY they are important to database design.  Why do I care if an entity is strong or weak?  Why do I care if a relationship is strong or weak?  Why do I care if participant optionality is optional or mandatory?

Database Design

Databases are organized collections of data, most commonly accessed through management systems including schemas, tables, queries and processes that allow users to enter and manipulate the information or utilize it in other fashions, such as with web applications or for reporting purposes.