PHP: Creating big HTML-table efficiently - php

Question

I'm making a HTML table based on certain information in my MySQL database. The tables I need from the database hold the data for rows (rowid, rowname), columns (columnid, columnname) and cell data. A table, that links IDs from rows and columns together (cellid, rowid, columnid, somedata).
The table looks something like this:
__________| column1 | column2 | column3 | ...
row1 | somedata | somedata | |
----------|----------|----------|----------|-----
row2 | somedata | | somedata |
----------|----------|----------|----------|-----
... | | | |
My approach was to use several nested foreach loops, something like this:
$rows = new Rows(); //These objects are containers for objects
$columns = new Columns(); //that hold some of the database data.
$alldata = new Alldata(); //MySQL queries within these objects are irrelevant, I think. They already get the relevant data
$count = count($alldata);
echo "<table>";
echo "<tr>";
echo "<td> </td>";
foreach ($columns->getColumns() as $column) {
echo "<td>".$column->getColumnname()."</td>";
}
echo "</tr>";
foreach ($rows->getRows() as $row) {
echo "<tr>";
echo "<td>".$row->getRowname()."</td>";
foreach ($columns->getColumns() as $column) {
$last = 1;
foreach ($alldata->getAlldata() as $data) {
if ($data->getCID() == $column->getID() & $data->getRID() == $row->getID()) { //If the column has data the related to the row
echo "<td>".$data->getSomedata()."</td>";
break;
}
if ($last == $count) { //if loop couldn't find any entries, it prints an empty cell
echo "<td> <td>";
}
$last++
}
}
echo "</tr>";
}
echo "</table>";
Bruteforcing, obviously this is not very efficient method when there are several hundred rows of data on any table in the database and I don't like this. Any ideas how to make this more efficient? Is there better way of creating a table like I need?
EDIT:
Pondering about this problem for a week has finally given me some answers. It was so simple!
I did a slight modification to my Column object class. Previously, my code went through all possible entries on celldata table in the database. Now Column object gets an array of celldata where columnid's match and I can do the comparison using only that data.
$rows = new Rows();
$columns = new Columns();
echo "<table>";
echo "<tr>";
echo "<td> </td>";
foreach ($columns->getColumns() as $column) {
echo "<td>".$column->getColumnname()."</td>";
}
echo "</tr>";
foreach ($rows->getRows() as $row) {
echo "<tr>";
echo "<td>".$row->getRowname()."</td>";
foreach ($columns->getColumns() as $column) {
$last = 1;
$count = count($column->getAlldata());
foreach ($column->getAlldata() as $data) {
if ($data->getCID() == $column->getID() & $data->getRID() == $row->getID()) {
echo "<td>".$data->getSomedata()."</td>";
break;
}
if ($last == $count) {
echo "<td> <td>";
}
$last++
}
}
echo "</tr>";
}
echo "</table>";
Much faster, although still bruteforcing but there's less amount of data to go through. Of course, now the problem is that Column objects may do quite a lot of MySQL queries, depending on how many Columns there are.

Answer 1

If you ensure that the data fetched from MySQL is correctly ordered in $alldata by joining the tables and specifying an ORDER BY clause in your query:
SELECT data.*
FROM data RIGHT JOIN rows USING (rowid) RIGHT JOIN columns USING (columnid)
ORDER BY rowname, columnname;
Then you only need to output each cell in order:
echo '<table>';
echo '<thead>'
echo '<tr>';
echo '<th> </th>';
foreach ($columns->getColumns() as $column) {
echo '<th scope="col">', htmlentities($column->getColumnname()), '</th>';
}
echo '</tr>';
echo '</thead>';
echo '<tbody>';
$data = $alldata->getAlldata();
foreach ($rows->getRows() as $row) {
echo '<tr>';
echo '<th scope="row">', htmlentities($row->getRowname()), '</th>';
foreach ($columns->getColumns() as $column) {
$d = each($data);
echo '<td>', ($d ? htmlentities($d[1]->getSomedata()) : ' '), '</td>';
}
echo '</tr>';
}
echo '</tbody>';
echo '</table>';

Answer 2

The best way to solve this would be to rewrite the query for $alldata so that it is in the order you want like eggyal suggested. If you can't do that for some reason, you could iterate through $alldata in the beginning and create a properly indexed array from it. Something like this:
$ordereddata = array();
foreach($alldata as $d) {
$ordereddata[$d->getCID()][$d->getRID()] = $d->getSomedata();
}
Now you can replace your foreach($alldata) loop with this:
if(isset($ordereddata[$column->getID()][$row->getID()])) {
echo "<td>{$ordereddata[$column->getID()][$row->getID()]}</td>";
} else {
echo "<td> </td>";
}