√70以上 er diagram parent child relationship 212658-Parent child relationship in er diagram
In the below ER Diagram, 'Payment' is the weak entity 'Loan Payment' is the identifying relationship and 'Payment Number' is the partial key Primary Key of the Loan along with the partial key would be used to identify the records Example2 The existence of rooms is entirely dependent on the existence of a hotel So room can be seen as the weak entity of theRecursive) is a relationship type between two occurrences of the same entity type Examples I Marriage between Person and itself I ParentChild between Person and itself I PartSubPart between Part and itself With each entity type in a cyclic relationship type we associate a role, represented by labels on lines in an ERD A parentchild relationship between two tables can be created only when there is a PRIMARY KEY in one table and FOREIGN KEY in another table Syntax diagram SQL JOIN of three tables Example SQL JOIN three or more tables Here is an example of SQL join three tables with conditions Sample table agents ...
