Database design erd table tool software#

In a traditional American marriage, a man can be married to only one woman a woman can be married to only one man.Ī child has exactly one biological father a father can have many biological children.Ī student can enroll in many classes a class can have many enrolled students. The DDL generated by your data modeling software tool necessary to create the database you have designed. Loan period for tools is seven (7) days and no more than six (6) items may be borrowed at any one time, with no more than two (2) power tools. many-to-many relationship: In relational database design, a many-to-many (M:N) relationship exists when, for one instance of entity A, there exists zero, one, or many instances of entity B and for one instance of entity B, there exists zero, one, or many instances of entity A. LA County Library cardholders over the age of 18 are eligible to borrow tools from the Tool Lending Library.one-to-many relationship: (abbreviated 1:N) In relational database design, a one-to-many (1:N) relationship exists when, for one instance of entity A, there exists zero, one, or many instances of entity B but for one instance of entity B, there exists zero or one instance of entity A.one-to-one relationship: In relational database design, a one-to-one (1:1) relationship exists when zero or one instance of entity A can be associated with zero or one instance of entity B, and zero or one instance of entity B can be associated with zero or one instance of entity A.