Currently in my application I have a single table that is giving me a bit of trouble. The issue at hand is I have a value object that is mapped to this table. When the data is returned to me as an array of value objects, I have to then loop through this array and begin my recursion by matching the ParentID to parent ObjectID’s.
The column ParentID is either null (acts a parent) or it holds the value of an ObjectID.
I know there has to be a better way to create this data structure so that I do not have to do recursive loops to match ParentID’s with their ObjectID’s.
Any help with this is greatly appreciated.
Here is the table in describe form:
+----------------+------------------+------+-----+---------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+----------------+------------------+------+-----+---------------------+-----------------------------+
| ObjectID | int(11) unsigned | NO | PRI | NULL | auto_increment |
| ObjectHeight | decimal(6,2) | NO | | NULL | |
| ObjectWidth | decimal(6,2) | NO | | NULL | |
| ObjectX | decimal(6,2) | NO | | NULL | |
| ObjectY | decimal(6,2) | NO | | NULL | |
| ObjectLabel | varchar(255) | NO | | NULL | |
| TemplateID | int(11) unsigned | NO | MUL | NULL | |
| ObjectTypeID | int(11) unsigned | NO | MUL | NULL | |
| ParentID | int(11) unsigned | YES | MUL | NULL | |
| CreationDate | datetime | YES | | 0000-00-00 00:00:00 | |
| LastModifyDate | timestamp | YES | | NULL | on update CURRENT_TIMESTAMP |
+----------------+------------------+------+-----+---------------------+-----------------------------+e
You could use a nested set model. See the very good explanation here: http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/