package io.ebean.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

Specify how a foreign key constraint should be defined.

We can specify if a constraint should not be defined at all or control the
onDelete and onUpdate modes used.

Example: On delete cascade

 @DbForeignKey(onDelete = ConstraintMode.CASCADE) 
@ManyToOne

RelatedBean parent;
}

Example: No foreign key

// No FK Constraint
 @DbForeignKey(noConstraint=true)
@ManyToOne

RelatedBean parent;
}


Example: On delete set null

 @DbForeignKey(onDelete = ConstraintMode.SET_NULL)
@ManyToOne

RelatedBean parent;
}/**
 * Specify how a foreign key constraint should be defined.
 * <p>
 * We can specify if a constraint should not be defined at all or control the
 * onDelete and onUpdate modes used.
 * <p>
 * <h3>Example: On delete cascade</h3>
 * <pre>{@code
 *
 * @DbForeignKey(onDelete = ConstraintMode.CASCADE)
 * @ManyToOne
 * RelatedBean parent;
 *
 * }</pre>
 * <p>
 * <h3>Example: No foreign key</h3>
 * <pre>{@code
 *
 * // No FK Constraint
 * @DbForeignKey(noConstraint=true)
 * @ManyToOne
 * RelatedBean parent;
 *
 * }</pre>
 * <p>
 * <p>
 * <h3>Example: On delete set null</h3>
 * <pre>{@code
 *
 * @DbForeignKey(onDelete = ConstraintMode.SET_NULL)
 * @ManyToOne
 * RelatedBean parent;
 *
 * }</pre>
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface DbForeignKey {

	
Specify the onDelete mode. Typically will default to RESTRICT (aka No Action).
/**
	 * Specify the onDelete mode. Typically will default to RESTRICT (aka No Action).
	 */
	ConstraintMode onDelete() default ConstraintMode.RESTRICT;

	
Do NOT change this - seriously, don't do it.

Your primary keys should never change by design. We should orientate the design to
support primary keys that change (and instead find better non mutating primary keys).
Oracle go to the point of actively not supporting "on update" for this reason.


So yes, we can specify the onUpdate mode but I don't expect anyone to change this.

/**
	 * Do NOT change this - seriously, don't do it.
	 * <p>
	 * Your primary keys should never change by design. We should orientate the design to
	 * support primary keys that change (and instead find better non mutating primary keys).
	 * Oracle go to the point of actively not supporting "on update" for this reason.
	 * </p>
	 * <p>
	 * So yes, we can specify the onUpdate mode but I don't expect anyone to change this.
	 * </p>
	 */
	ConstraintMode onUpdate() default ConstraintMode.RESTRICT;

	
Set to true when we do not wish any foreign key constraint to be created.
When this is set to true the onDelete and onUpdate have no effect.
/**
	 * Set to true when we do not wish any foreign key constraint to be created.
	 * When this is set to true the onDelete and onUpdate have no effect.
	 */
	boolean noConstraint() default false;

	
Set to true when we do not wish an index to be created on the foreign key column(s).
/**
	 * Set to true when we do not wish an index to be created on the foreign key column(s).
	 */
	boolean noIndex() default false;
}