3
I wanted to know the real difference and between
$sql = 'select * from tbl_blablabla';
$result = $connect->prepare(sql);
and
$result = $connect->prepare('select * from tbl_blabla');
Not just in this particular case, but several other cases I’ve seen a lot of people doing a lot of variable to receive parameters and typing less in example 2, does it affect performance? Security? If it affects security, what exactly happens?
7
In this example the difference is that you wrote an extra line in the first.
There’s zero advantages there, and the only reason I see people using it like that is that they don’t know what is a variable and what it is for. Of course, the taste of the person may be another reason, but there is reason.
If it had a more complex expression, I would understand that it was done earlier and kept in a variable with a significant name. A name that is not informative or indicates obviousness does not increase readability.
If the value was used elsewhere there is the exact reason for a variable to exist.
Do something because one day you might need to violate the principle of YAGNI, and a certain form of KISS. Having a good IDE change the expression to a variable if you need it is the simplest thing you have.
It’s not to save code, it’s to simplify code. Putting the declaration/definition of what you will use as close as possible to where it is used usually gives more readability. Long code is harder to follow. Apart from the semantics that if there is a variable it is because it must be used in several places. Code is expression, when expressed wrong gives the wrong idea and makes the code convoluted.
Depending on the language there is a difference in performance and even memory consumption.
Never do anything without knowing why you’re doing it. Don’t go on automatic, don’t follow rules that others have said is good. Look for what’s good for you, but do it with choice awareness.
Very good answer. You said that there are languages in which this can consume memory, is there any reason? Where do you win in this?
There are languages that will allocate the space for the variable and put the result there and then copy that result where you need it, that’s cost. Some languages can make the variable disappear since it is not needed and you can use the direct registrar.
Exactly as you said in the post, people do not seem to understand the function of a variable in the code, I always believed that had something to do with security that the variable was able to encapsulate and protect the information. Did you find it strange that a variable (the name says) only receives 1 single static value in the whole code.
1
It’s basically the same thing:
int numero = 1;
printf("%d",numero);
and
printf("1");
The difference is that in the first you had to declare the variable (and store memory for an integer, 4 bytes) and in the second no.
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It is usually by readability or error handling, I think there is a specific reason. For example, there could be an error in the line
$sqlthat if you put directly on the line$resultthe difficulty of finding the error is greater. It’s just an example.– bio
It does not affect performance or security. It only affects your code. I am one of those who prefer to use the first example. For me it is more readable and practical, in case I need to use the same variable later, it already exists, just use.
– Francisco
@Francisco, you’re right, there’s still the reuse I forgot to mention.
– bio