Fetch Type and CascadeType

Posted On: 2023-03-26 15:54:02 Spring, Spring Boot

FetchType (select) => It is a enum, having 2 possible values.

EAGER: While fetching(selecting) parent data we can get child data,Employee with Profile object ,It is default for Non -Collection Type (EAGRER LOADING/EARLY LOADING)
LAZY : While fetching(selecting) parent data we dont get child data,Employee object only  ,It is default for Collection Type  (LAZY LOADING/LATE LOADING)

*) When child is Many -- default is LAZY

*) When child is One -- default is EAGER

CascadeType
*) When we perfom one operation on parent object if we want to perform same operation on child also then it is called as Cascading (connected operation)

@Entity

@Table(name="prodtab")

public class Product {

@OneToMany(cascade = CascadeType.ALL)

@JoinColumn(name="midFk")

private Set mobs; //HAS-A

}

*) For Collections cascading is good approch.

@OneToMany(cascade = CascadeType.PERSIST) //only for save

@OneToMany(cascade = CascadeType.REMOVE)//only for delete

*) There is no default value for cascading, if we do not write any cascacde type.