Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <pre><code>/** * Rule #0: never trust users input! */ //sanitize integer value $id = intval($_GET['id']); //sanitize string value; $name = mysql_real_escape_string($_POST['name']); //1. using `dbname`. is better than using mysql_select_db() //2. names of tables and columns should be quoted by "`" symbol //3. each variable should be sanitized (even in LIMIT clause) $q = mysql_query("UPDATE `dbname`.`tablename` SET `name`='".$name."' WHERE `id`='".$id."' LIMIT 0,1 "); if ($q===false) { trigger_error('Error in query: '.mysql_error(), E_USER_WARNING); } else { //be careful! $name contains user's data, remember Rule #0 //always use htmlspecialchars() to sanitize user's data in output print htmlspecialchars($name).' updated'; } ######################################################################## //Example, how easily is to use set_error_handler() and trigger_error() //to control error reporting in production and dev-code //Do NOT use error_reporting(0) or error_reporting(~E_ALL) - each error //should be fixed, not muted function err_handler($errno, $errstr, $errfile, $errline) { $hanle_errors_print = E_ALL &amp; ~E_NOTICE; //if we want to print this type of errors (other types we can just write in log-file) if ($errno &amp; $hanle_errors_print) { //$errstr can contain user's data, so... Rule #0 print PHP_EOL.'Error ['.$errno.'] in file '.$errfile.' in line '.$errline .': '.htmlspecialchars($errstr).PHP_EOL; } //here you can write error into log-file } set_error_handler('err_handler', E_ALL &amp; ~E_NOTICE &amp; E_USER_NOTICE &amp; ~E_STRICT &amp; ~E_DEPRECATED); </code></pre> <p><em><strong>And some explanation of comments:</em></strong> </p> <pre><code>//1. using `dbname`. is better than using mysql_select_db() </code></pre> <p>With using mysql_select_db you can create errors, and it will be not so easy to find and fix them.<br> For example, in some script you will set db1 as database, but in some function you need to set db2 as database.<br> After calling this function, database will be switched, and all following queries in script will be broken or will broke some data in wrong database (if names of tables and columns will coincide).</p> <pre><code>//2. names of tables and columns should be quoted by "`" symbol </code></pre> <p>Some names of columns can be also SQL-keywords, and using "<strong>`</strong>" symbol will help with that.<br> Also, all string-values, inserted to query, should be quoted by <strong>'</strong> symbol. </p> <p><code>//always use htmlspecialchars() to sanitize user's data in output</code><br> It will help you to prevent <a href="http://en.wikipedia.org/wiki/Cross-site_scripting" rel="nofollow">XSS-attacks</a>.</p>
    singulars
    1. This table or related slice is empty.
    1. POReference: What is a perfect code sample using the MySQL extension?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USOZ_
    1. USOZ_
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CONice, I like it! I also like the error handler, but maybe it's too much for a newbie to grasp here - would it be an option to remove it for now, or move it to the bottom as "optional"? (I edited out the `i` in `mysqli`)
      singulars
      1. PO
      1. USPekka 웃
    2. COfeel free to edit mistakes in my broken English :)
      singulars
      1. PO
      1. USOZ_
    3. CO@Pekka I will try to take more focus on mysql_, will edit now.
      singulars
      1. PO
      1. USOZ_
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload