8 Tips for PHP and MySQL Development

1. The use of arrays in PHP
When operating databases, it is very helpful to use associatively-indexed arrays. Let’s look at a basic array traversal in digital format:

$temp[0 ] = "richmond";
$temp[1] = "tigers";
$temp[2] = "premiers";

for($x=0;$x {
echo $temp[$x];
echo " ";
}
?>

However, another way to save code is:

$temp = array("richmond", "tigers", "premiers");
foreach ($temp as $element)
echo "$element ";
?>

foreach can also output text subscripts:

$temp = array ("club" => "richmond",
"nickname" =>"tigers",
"aim" => "premiers");

foreach ($temp as $key => $value)
echo "$key : $value ";
?>
The PHP manual describes about 50 functions for working with arrays.

2. Adding variables to the PHP string

This is very simple:

$temp = "hello"
echo "$temp world";
?>

But what needs to be explained is that , although the following example has no errors:
$temp = array("one" => 1, "two" => 2);
// Output:: The first element is 1
echo " The first element is $temp[one].";
?>

But if the following echo statement is not enclosed in double quotes, an error will be reported, so it is recommended to use curly braces:

$temp = array("one" => 1, "two" => 2);
echo "The first element is {$temp["one"]}.";
?>

3. Use association Array access query results
Look at the following example:

$connection = mysql_connect("localhost", "albert", "shhh");
mysql_select_db("winestore", $connection);

$ result = mysql_query("SELECT cust_id, surname,
firstname FROM customer", $connection);

while ($row = mysql_fetch_array($result))
{
echo "ID:t{$row["cust_id"]} n";
echo "Surnamet{$row["surname"]}n";
echo "First name:t{$row["firstname"]}nn";
}
?>

function mysql_fetch_array() Put a row of the query result into the array, which can be referenced in two ways at the same time. For example, cust_id can be referenced in the following two ways at the same time: $row["cust_id"] or $row[0]. Obviously, the former is much more readable than the latter.

In multi-table query, if two column names are the same, it is best to use aliases to separate them:

SELECT winery.name AS wname,
region.name AS rname,
FROM winery, region
WHERE winery.region_id = region .region_id;

The reference of the column name is: $row["wname"] and $row["rname"].

When the table name and column name are specified, only the column name is quoted:

SELECT winery.region_id
FROM winery

The reference of the column name is: $row["region_id"].

The reference of the aggregate function is the reference name:

SELECT count(*)
FROM customer;

The reference of the column name is: $row["count(*)"].

4. Pay attention to common PHP bugs

Common PHP error correction problems are:

No page rendered by the Web browser when much more is expected
A pop-up dialog stating that the "Document Contains No Data"
A partial page when more is expected

Most of the reasons for these situations are not the logic of the script, but bugs in the HTML or bugs in the HTML generated by the script. For example, if closing tags like , , are missing, the page cannot be refreshed. The solution to this problem is to look at the source code of the HTML.

The above are the tips for PHP and MySQL development. I hope it can be helpful to everyone. If you want to get more content, you can pay attention to the PHP Chinese website (www.php.cn)!