Understanding fetch_assoc()

Question

I am trying to understand how/why fetch_assoc works the way it does. I have the following piece of code:

$results = $connectToDb->fetch(\"SELECT * FROM cust         


        

Answer 1

Lets try to understand your code and how it works:

$results = $connectToDb->fetch("SELECT * FROM customer");

A variable $results has a collection of rows which are returned by a query. The size of the collection can be from 0 to n.

$resultsArray = $results->fetch_assoc();

This line fetch the first element from the collection. If the collection is empty it will return NULL.

while($row = $results->fetch_assoc()){
}

It can be decoupled in the following steps:

1. Calculate $row = $results->fetch_assoc() and return array with elements or NULL.
2. Substitute $row = $results->fetch_assoc() in while with gotten value and get the following statements: while(array(with elements)) or while(NULL).
3. If it's while(array(with elements)) it resolves the while condition in True and allow to perform an iteration.
4. If it's while(NULL) it resolves the while condition in False and exits the loop.