What is $ stmt in PHP

Question

What is $ stmt and what is the purpose? what does this mean.

I am following a tutorial that uses prepared statements and looked at stmt in the manual: http://php.net/manual/en/class.mysqli-stmt.php

and see that it is a class that "represents a prepared statement", which, I think, is a prepared sql statement into which you insert a variable. although I don’t see how this identifier differs from storing the sql statement as a string, and then manipulating the string to add variables when you need to?

Answer 1

" $stmt " obviously (I think) means "expression". As a variable name it is arbitrary, you can name this variable what you want. $stmt is rather rather idiomatic.

A prepared statement as such is a database function. The database itself takes a request in two stages: first, the structure of the request with placeholders, and secondly, data for filling placeholders. The assertion objects on the PHP side represent this separation and should provide you with a handle representing the prepared statement on the SQL server side.

The point of this separation is that there is no way to have problems with SQL injection due to improper escaping of arbitrary string values; it is also useful for performance if you reuse this prepared statement more than once.

Answer 2

Working with statements is much safer than inserting variables into a regular SQL string. Using statements, you prohibit SQL injection. Take a look at:

How does SQL injection from the "Bobby Tables" table of XKCD comic work?

&

How to prevent SQL injection in PHP?

Answer 3

What is $ stmt and what is the purpose?

This is a variable and stores the value.

People use it for approval - others are a bit more inventive with variable names

Answer 4

  I think your trying to get DESC AND ASC as VARIABLES FROM SCREEN AND TRYING TO APPEND THEM BASED ON type you have choosed to the query , the code below may help you. you can try like this <?php /* if you select column names from screen using and html and angular*/ $fruitcolumn=$_GET['column']; // values will get here from screen using html forms $sort=$_GET['sortorder']; // values will get here from screen using html forms if($sort=='DESC'){ $sortbyorder='DESC'; }else{ $sortbyorder='ASC'; } /* or you can simply hard code variables with strings */ $fruitColumn='bananas' $sortbyORDER= 'DESC' /* please comment out based on your needs */ // USE this type of syntax use get data from screen $sql_fruits="SELECT * FROM fruits ORDER BY '".$fruitcolumn."' '".$sortbyorder."' "; // use this type of syntax for hard coded variables $sql_fruits="SELECT * FROM fruits ORDER BY $fruitcolumn $sortbyorder /* now to execute query you need to use $stmt variable for preparing the query and for executing to the query */ $stmt = $conn->prepare($sql_fruits); $stmt->execute(); $fruitsinfo=$stmt->fetchAll(); // now you will get data from query , to check data you can simply use //print_r($fruitsinfo); ?>