Insert unknown number of rows into MySQL using PHP - php

Question

I am trying to insert an unknown number of rows into MySQL using PHP. This is how it should work:
Javascript parses HTML DOM to create a multi-dimensional array based on a css class. The array will have a certain number of rows(or sub-arrays) corresponding to the number of elements that have that class. (This could be any integer 0 or greater... obviously).
Then, on a JavaScript event, the array is sent to a PHP script.
The PHP script will INSERT data from the array into MySQL.
My problem is that I don't know how to tell my PHP script how many values are in the array. And I don't know how to write the mysql_query() without knowing the number of values (or rows) that should be inserted.

Answer 1

You can insert more than one row at a time to MySQL:
INSERT INTO table1 (column1, column2, ...) VALUES (value_col1, value_col2), (value2_col1, value2_col2), ...;
In PHP, you can build your query by looping through rows and adding them to the SQL string:
$sql = "INSERT INTO table1 (col1, col2) VALUES ";
foreach($rows as $i=>$row) {
if ($i>0) {
$sql .= sprintf(",(%s,%s)", $row["col1_value"], $row["col2_value"]);
} else {
$sql .= sprintf("(%s,%s)", $row["col1_value"], $row["col2_value"]);
}
}
mysql_query($sql);
You have to be sure to properly escape your values depending upon what you're actually inserting.

Answer 2

Why don't you prepare a two dimensional array while searching with the css class identifier like this?
//This is jquery code - you can write javascript to do the same
$(`.class`).each(function(i,e){resultsArray.push($(this).val());});
This will save you from the headache of traversing a multidimensional array in the backend and you can simply do a count() in you PHP code and the following query preparation.
Query preparation
Assuming you have a two dimensional array you can use a bulk insert query like this:-
INSERT INTO tablename (a,b)
VALUES
('1', 'one'),
('2', 'two'),
('3', 'three')
And prepare the query dynamically using PHP like this -
$counter = 0;
$valuesPart = NULL;
foreach($_POST as $each)
{
if($counter > 0)
$appendComma = ",";
else
$appendComma ="";
$valuesPart .= $appendComma."(".$each['key1'].",".$each['key2'].")";
$counter++;
}
if(!empty($valuesPart))
$mysql_query = "INSERT INTO tablename (a,b) VALUES ".$valuesPart;
So, you don't need to know how many results are to be actually inserted.
If you stay with the multidimensional array, you will probably need to code or search for a code to traverse the multidimensional array which will probably involve recursion and a lot of complex code. There will be many chances of errors and it will be a slower (may be little but a finite amount which is not necessary).

Answer 3

So I assume the array is getting to PHP successfully, through $_POST or whatever? If you aren't sure then do a var_dump or echo_r so we can see.
EDIT - wow I put explode where I meant implode several times. fixed.
Assuming that it is, and that each 'sub' array is an associative array in form
[0]
'id' => 1
'name' => 'Billy'
'DOB' => .....
[1]
etc.
And the code to build a single query inserting all rows, like this INSERT INTO table ('f1','f2',f3') VALUES ('v11', 'v22', 'v33'), ('v21', 'v22', 'v23'), ......
$escapeAndQuote = function($x) {return "'".mysql_real_escape_string($x)."'";};
$rowwise = function($x) {return '('. implode(', ', array_map($escapeAndQuote, $x)) .')';
$fieldString = $rowwise(array_keys($arr[0]));
$valString = implode(', ', array_map($rowwise, $arr));
$sql = "INSERT INTO table $fieldString VALUES $valString";
mysql_query($sql, $conn);

Answer 4

Use a foreach loop to cycle through the array.
// Example:
foreach($submitted_array as $insert_array)
{
//php and mysql insert query here
}
Perhaps prepared statements would assist you in your endeavors. Essentially you will declare a generic insert statement and then "bind" values to each input. Read more on PHP PDO Prepared Statements.