How to Traversal this? - php

Question

I am working on an application that has a web based backend and a Android app based front end.
The backend is used to input data into MySQl (using PHP) and then generate a JSON which is then supplied to the Android App (front end) and displayed.
So here is what I have:
This is my Database
CREATE TABLE IF NOT EXISTS `tddept` (
`deptId` int(11) NOT NULL AUTO_INCREMENT,
`deptName` varchar(50) NOT NULL,
`deptIsRoot` tinyint(1) NOT NULL,
`deptHasChild` tinyint(1) NOT NULL,
`deptParentId` int(11) NOT NULL,
PRIMARY KEY (`deptId`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=16 ;
--
-- Dumping data for table `tddept`
--
INSERT INTO `tddept` (`deptId`, `deptName`, `deptIsRoot`, `deptHasChild`, `deptParentId`) VALUES
(2, 'One', 1, 1, 0),
(3, 'Two', 1, 1, 0),
(4, 'Three', 1, 1, 0),
(5, 'One1', 0, 0, 2),
(6, 'One2', 0, 0, 2),
(7, 'One3', 0, 0, 2),
(12, 'Two1', 0, 0, 3),
(13, 'Three1', 0, 0, 4),
(14, 'Dept1', 1, 1, 0),
(15, 'dept1.1', 0, 0, 14);
My intention is simple to create a tree structure. only that there are multiple root nodes. and hence multiple leafs.
If put in simple words, I am trying to create a directory tree structure. I would want to display the data in the above table in to a dropdown menu (i.e. using <select> and <option>) as:
One
One1
One2
One3
Two
Two1
Three
Three1
Dept1
dept1.1
Where One, Two, Three, Dept1 are root departments while the rest are sub-departments.
There can definitely be situations in the future where in I might have to have something like:
- One
- - One1
- - - One1a
- - - One1b
so on and so forth.
How can I traversal through them using Core PHP and how can I display them in the very structure as above in to a <select>/<option> (dropdown) menu.
PS: any heads up on JSON would also be a great help.

Answer 1

Here's the solution for image2
echo '<select>';
structureTree(0,0);
echo '</select>';
function structureTree($deptParentId, $level){
$result = getDataFromDb($deptParentId); // change this into SQL
foreach($result as $result){
echo '<option value="'.$deptParentId.'">'.str_repeat('-',$level).$result['deptName'].'</option>';
structureTree($result['deptId'], $level+2);
}
}
// mocking database record
function getDataFromDb($deptParentId)
{
$data = array(
array(
'deptId' => 1,
'deptName' => 'IT',
'deptParentId' => 0,
),
array(
'deptId' => 2,
'deptName' => 'Human Resources',
'deptParentId' => 1,
),
array(
'deptId' => 3,
'deptName' => 'Opreational',
'deptParentId' => 1,
),
array(
'deptId' => 4,
'deptName' => 'Networking Department',
'deptParentId' => 1,
),
array(
'deptId' => 5,
'deptName' => 'Software Development',
'deptParentId' => 1,
),
array(
'deptId' => 6,
'deptName' => 'Mobile Software Development',
'deptParentId' => 5,
),
array(
'deptId' => 7,
'deptName' => 'ERP',
'deptParentId' => 5,
),
array(
'deptId' => 8,
'deptName' => 'Product Development',
'deptParentId' => 5,
),
);
$result = array();
foreach ($data as $record) {
if ($record['deptParentId'] === $deptParentId) {
$result[] = $record;
}
}
return $result;
}
regarding 1.png Here's the SQL based on your sample db table
SELEC dep.deptId As DepId
,dep.deptName As DepartmenName
,parent.deptId As ParentId
,parent.deptName As ParentDepartmentName
FROM tddept As dep
JOIN tddept As parent ON parent.deptParentId = dep.deptId;

Answer 2

recursion is the solution for this problem. While the parent still has a child then it keeps querying until there's no child left.
e.g
One
.One1
.One2
.One3
Here's the php application
function structureTree($depParentId = 0){
$result = queryFunction("SELECT *FROM
tddept WHERE deptParentId = '$depParentId'");
foreach($results as $result){
echo $result['deptName'].'<br/>';
structureTree($resultp['deptParentId']);
}
}
structureTree();