polish the jdoc for @onDelete and OnDeleteAction

Author: gavinking

hibernate-core/src/main/java/org/hibernate/annotations/OnDelete.java

@@ -78,6 +78,17 @@
  *     deleted in the persistence context, and are not automatically
  *     evicted from the second-level cache.
  * </ul>
+ * <p>
+ * Other options such as {@link OnDeleteAction#SET_NULL} and
+ * {@link OnDeleteAction#SET_DEFAULT} are much less commonly used.
+ * Note that {@code @OnDelete(SET_DEFAULT)} should be used together
+ * with {@link ColumnDefault @ColumnDefault}.
+ * <pre>
+ * &#064;ManyToOne
+ * &#064;OnDelete(action = OnDeleteAction.SET_DEFAULT)
+ * &#064;ColumnDefault("-1")
+ * Parent parent;
+ * </pre>
  *
  * @author Emmanuel Bernard
  */

hibernate-core/src/main/java/org/hibernate/annotations/OnDeleteAction.java

@@ -27,25 +27,33 @@ public enum OnDeleteAction {
 
 	/**
 	 * Cascade deletion of the parent to the child.
+	 * <p>
+	 * Produces a foreign key constraint with {@code on delete cascade}.
 	 */
 	CASCADE,
 
 	/**
 	 * Prevents deletion of the parent by raising an error immediately.
+	 * <p>
+	 * Produces a foreign key constraint with {@code on delete restrict}.
 	 *
 	 * @since 6.2
 	 */
 	RESTRICT,
 
 	/**
 	 * Set the referencing foreign key to null.
+	 * <p>
+	 * Produces a foreign key constraint with {@code on delete set null}.
 	 *
 	 * @since 6.2
 	 */
 	SET_NULL,
 
 	/**
 	 * Set the referencing foreign key to its default value.
+	 * <p>
+	 * Produces a foreign key constraint with {@code on delete set default}.
 	 *
 	 * @since 6.2
 	 */

hibernate-core/src/test/java/org/hibernate/orm/test/ondelete/toone/ToOneOnDeleteSetNullTest.java

@@ -10,11 +10,11 @@
 import org.hibernate.annotations.ColumnDefault;
 import org.hibernate.annotations.OnDelete;
 import org.hibernate.annotations.OnDeleteAction;
-import org.hibernate.dialect.SybaseDialect;
+import org.hibernate.testing.orm.junit.DialectFeatureChecks;
 import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.RequiresDialectFeature;
 import org.hibernate.testing.orm.junit.SessionFactory;
 import org.hibernate.testing.orm.junit.SessionFactoryScope;
-import org.hibernate.testing.orm.junit.SkipForDialect;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 
@@ -38,11 +38,7 @@ public void tearDown(SessionFactoryScope scope) {
 	}
 
 	@Test
-	@SkipForDialect(
-			dialectClass = SybaseDialect.class,
-			matchSubTypes = true,
-			reason = "Sybase does not support on delete actions"
-	)
+	@RequiresDialectFeature(feature = DialectFeatureChecks.SupportsCascadeDeleteCheck.class)
 	public void testManyToOne(SessionFactoryScope scope) {
 		scope.inTransaction(
 				session -> {

hibernate-core/src/test/java/org/hibernate/orm/test/ondelete/toone/ToOneOnDeleteTest.java

@@ -7,16 +7,13 @@
 import jakarta.persistence.Entity;
 import jakarta.persistence.Id;
 import jakarta.persistence.ManyToOne;
-
 import org.hibernate.annotations.OnDelete;
 import org.hibernate.annotations.OnDeleteAction;
-import org.hibernate.dialect.SybaseDialect;
-
-import org.hibernate.community.dialect.TiDBDialect;
+import org.hibernate.testing.orm.junit.DialectFeatureChecks;
 import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.RequiresDialectFeature;
 import org.hibernate.testing.orm.junit.SessionFactory;
 import org.hibernate.testing.orm.junit.SessionFactoryScope;
-import org.hibernate.testing.orm.junit.SkipForDialect;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 
@@ -43,12 +40,7 @@ public void tearDown(SessionFactoryScope scope) {
 	}
 
 	@Test
-	@SkipForDialect(
-			dialectClass = SybaseDialect.class,
-			matchSubTypes = true,
-			reason = "Sybase does not support on delete actions"
-	)
-	@SkipForDialect(dialectClass = TiDBDialect.class)
+	@RequiresDialectFeature(feature = DialectFeatureChecks.SupportsCascadeDeleteCheck.class)
 	public void testManyToOne(SessionFactoryScope scope) {
 		scope.inTransaction(
 				session -> {