PHP For Loop Through Multiple Array Then Add to Database

When it comes to working with arrays in PHP, one common task is to loop through multiple arrays and perform operations on them. This can be particularly useful when retrieving data from a database, as described in Chapter 7.

One way to achieve this is by using the `foreach` loop. The basic syntax of the `foreach` loop is as follows:

```php

$dinner = array('Sweet Corn and Asparagus', 'Eggplant with Chili Sauce');

foreach ($dinner as $key => $value) {

// code to be executed for each element in the array

}

```

In this example, the `$key` variable takes on the value of each key in the array (i.e. 'Sweet Corn and Asparagus' and 'Eggplant with Chili Sauce'), while the `$value` variable takes on the corresponding value.

Another way to use the `foreach` loop is by specifying a secondary array as an argument, like so:

```php

$meal = array(

'breakfast' => 'Walnut Bun',

'lunch' => 'Cashew Nuts and White Mushrooms'

);

foreach ($meal as $key => $value) {

// code to be executed for each element in the array

}

```

In this case, the `$key` variable takes on the value of each key in the secondary array (i.e. 'breakfast' and 'lunch'), while the `$value` variable takes on the corresponding value.

When working with arrays that come from a database, it's often necessary to loop through the data and perform operations on it. For example, you might want to add the data to a new table in the database. To do this, you can use a combination of `foreach` loops and database queries.

Here is an example of how you might use the `foreach` loop to add data from multiple arrays to a database:

```php

// assume that $dinner and $meal are already populated with data

$database = mysqli_connect('localhost', 'username', 'password', 'database');

if (!$database) {

die('Could not connect: ' . mysqli_error($database));

}

foreach ($dinner as $key => $value) {

foreach ($meal as $meal_key => $meal_value) {

// query to add data to the database

$query = 'INSERT INTO mytable (key, value, meal_key, meal_value)

VALUES ('$key', '$value', '$meal_key', '$meal_value')';

mysqli_query($database, $query);

}

mysqli_close($database);

```

In this example, the `foreach` loop is used to iterate through each element in both arrays. For each element, a database query is executed to add the data to a new table.

By using the `foreach` loop and combining it with database queries, you can easily manipulate and work with data from multiple arrays in PHP.

Php for loop through multiple array then add to database