8 tips developed by PHP and MySQL

Source: www.freeelamp.com

Lamp architecture website, I used to pay more attention to installation / configuration, and the relative development is relatively small, because I have fewed development. The original text of this article is from:

Published on the o'reilly network (http://www.oreillynet.com/)

http://www.oreillynet.com/pub/a/onlamp/2002/04/04/webdb.html

After reading, it is quite inspired. Some problems encountered in the previous development, the blades are solved. So translate out and share it.

1. Use of PHP

When operating the database, use the associative array (Associative-indexed arrays) is very helpful. Here we look at an array traversal of a basic digital format:

$ TEMP [0] = "richmond";

$ TEMP [1] = "TiGERS";

$ TEMP [2] = "premiers";

For ($ x = 0; $ x

{

Echo $ TEMP [$ x];

echo ""

}

?>

However, another way to save the 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" => "premier");

Foreach ($ TEMP AS $ Key => $ VALUE)

Echo "$ key: $ value";

?>

Approximately 50 functions for processing arrays are described in the PHP manual.

2. Add variables in the PHP string

This is very simple:

$ TEMP = "Hello"

Echo "$ TEMP World";

?>

However, it should be noted that although there is no error below:

$ TEMP = Array ("One" => 1, "Two" => 2);

// Output :: The first Element IS 1

Echo "The First Element IS $ TEMP [One]."

?>

However, if the Echo statement is not caused by double quotes, it is necessary to report an error. Therefore, it is recommended to use the curne brackets:

$ TEMP = Array ("One" => 1, "Two" => 2);

Echo "The first element is {$ TEMP [" one "]}."

?>

3. Adopt associative array access query results

Look at the example below:

$ 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 "Surname / T {$ ROW [" Surname "]} / n";

Echo "First Name: / t {$ ROW [" firstname "]} / n / n";

}

?>

Function mysql_fetch_array () puts a line of query results into an array, can be referenced in two ways, such as CUST_ID, can be used in both ways: $ ROW ["Cust_ID"] or $ ROW [0]. Obviously, the former readability is much better than the latter.

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

Select Winery.name as WNAME,

Region.name as RNAME,

From Winery, Region

WHERE WINERY.REGON_ID = region.region_id;

The column name is: $ ROW ["WNAME"] and $ ROW ["RNAME"].

In the case of specifying the table name and column name, only the column name:

Select Winery.Region_ID

From Winery

The column name is: $ ROW ["Region_ID"].

The reference to the aggregation function is the reference name:

SELECT Count (*)

From customer;

The column name is: $ ROW ["count (*)"].

4. Pay attention to common PHP bugs

Common PHP error correction is:

No page rendered by the web browser when more is expected

A pop-up dialog stating what the "Document Contains No Data"

A Partial Page When More Is Exected

Most of these situations are not the logic of scripts, but the bugs of bugs present in HTML, the HTML BUG generated by the script. For example, a closed tag similar to , , is missing, and the page cannot be refreshed. The way to solve this problem is to view the source code of HTML.

For complex, you cannot find out the page, you can analyze it through the W3C page checkpoint http://validator.w3.org/.

If there is no variable, or the variable definition error will make the program be quirky. For example, the following dead cycle:

For ($ counter = 0; $ counter <10; $ counter )

Myfunction ();

?>

Variable $ Counter is increasing, and $ counter is less than 10. Such errors are generally found by setting higher error reporting levels:

Error_Reporting (E_ALL);

For ($ counter = 0; $ counter <10; $ counter )

Myfunction ();

?>

5. Use the header () function to handle single part query

In many web database applications, some features often let users click on a connection, continue to stay in the current page, such a job I call it "single part query".

Below is a script called calling.php:

"- // W3C // DTD HTML 4.0 Transitional // En"

"http://www.w3.org/tr/html4/loose.dtd">