Drop constraints using CASCADE

Co-Authored-By: William Cekan <wcekan@oath.com>

hibernate-core/src/main/java/org/hibernate/dialect/H2Dialect.java

@@ -259,11 +259,6 @@ public class H2Dialect extends Dialect {
 		return false;
 	}
 
-	@Override
-	public boolean supportsIfExistsAfterTableName() {
-		return true;
-	}
-
 	@Override
 	public boolean supportsIfExistsBeforeConstraintName() {
 		return true;
@@ -434,8 +429,25 @@ public class H2Dialect extends Dialect {
 		return false;
 	}
 	
+	// Do not drop constraints explicitly, just do this by cascading instead.
 	@Override
-	public boolean supportsIfExistsAfterAlterTable() {
+	public boolean dropConstraints() {
+		return false;
+	}
+
+	@Override
+	public String getCascadeConstraintsString() {
+		return " CASCADE ";
+	}
+
+	// CASCADE has to be AFTER IF EXISTS in case it's after the tablename
+	@Override
+	public boolean supportsIfExistsAfterTableName() {
+		return false;
+	}
+
+	@Override
+	public boolean supportsIfExistsBeforeTableName() {
 		return true;
 	}