skip parameter value of a function - php

Question

Let suppose I have a function:
public function __getalldata($tablename,$tablefield=array(),$orderbyfield = 'id',$ascdesc = 'desc',$limit = 200,$type='result')
{
//Query generation according to above parameters
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->limit($limit)
->get();
return $data->$type();
}
This function is been used to many pages. Now, I want to skip the parameter $limit From function. That means I don't want to give $limit value but I need all data from database.
So what happens is if I have data like 600 and I don't know how many data I have, I don't give any parameter value to function (so by default it will take 500 data). But here I need all data so how can I manage this situation?

Answer 1

From https://www.codeigniter.com/user_guide/database/query_builder.html passing in NULL to the limit method as the first parameter will cause the limit statement to not limit anything - hence returning all of the rows (see on github):
public function limit($value, $offset = 0)
{
is_null($value) OR $this->qb_limit = (int) $value;
empty($offset) OR $this->qb_offset = (int) $offset;
return $this;
}
So in short if you want to skip the $limit parameter try setting its value to NULL. Like so...
public function __getalldata($tablename, $tablefield=array(), $orderbyfield = 'id', $ascdesc = 'desc', $limit = NULL, $type='result')
{
// Query generation according to above parameters
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->limit($limit)
->get();
return $data->$type();
}

Answer 2

I assume that the default value of $limit = 200 is already used in a number of places in the application. So the goal is to bypass the default when you want all the matching records. My suggestion is to simply pass the value 0 (zero) when you want them all. Then the only a small code change is required in the class method.
public function __getalldata($tablename, $tablefield=array(), $orderbyfield = 'id',
$ascdesc = 'desc',$limit = 200,$type='result')
{
if($limit > 0)
{
$this->db->limit($limit);
}
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->get();
return $data->$type();
}

Answer 3

public function __getalldata($tablename,$tablefield=array(),$orderbyfield = 'id',$ascdesc = 'desc',$limit = '',$type='result')
{
//Query generation according to above parameters
if($limit == '') {
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->get();
} else {
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->limit($limit)
->get();
}
return $data->$type();
}
Did you tried this?

Answer 4

As per MySQL documentation:
You can used bigint max values 18446744073709551615 to retrieve all data from MySQL.
So your function should look like this
public function __getalldata($tablename,$tablefield=array(),$orderbyfield = 'id',$ascdesc = 'desc',$limit = 18446744073709551615,$type='result')
{
//Query generation according to above parameters
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->limit($limit)
->get();
return $data->$type();
}

Answer 5

Note my main answer is at the bottom (IF you can't edit this function) but I have put in alternative answers as am unclear from OP as to if the function can/should be edited.
Edit this function
Your declared function has:
public function __getalldata($tablename,...,$limit = 200 ...){ ... }
Where the reference given in various answers here appearing to be adjusting this default value - the simplest solution is to NOT edit the default but set a special case and explicitly check for if $limit is exactly (and only) null.
To clarify:
PHP will use an explicitly set NULL value over any default value (in this case, 200).
So;
// within the function
if($limit !== null) {
//use limit in your PDO
}
This does not convert if $limit == 0 or other type-juggling cases, common to PHP
This above means that if no $limit value is given then default of 200 is used. If an explicit NULL value is given, that will be used instead.
Code
Please note this code is for example only and can probably be simplified further to better follow DRY patterns, but I don't know enough about CodeIgniter to do this here and now.
public function __getalldata($tablename,$tablefield=array(),$orderbyfield = 'id',$ascdesc = 'desc',$limit = 200,$type='result')
{
//Query generation according to above parameters
if($limit !== null){
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->limit($limit)
->get();
}
else {
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->get();
}
return $data->$type();
}
If you can't edit the function
I'm unclear on if you can (or want) to edit the function itself, if you're using Codeigniter, so instead simply refer an automatic value to the function arguments to return every valud row, no matter what (in effect removing the case for limit.
To do this use the PHP Constant PHP_INT_SIZE or PHP_INT_MAX which will return exactly that value. Reading this question/answer tells you more about this, but these constants should be self explanatory, as the maximum int values.
If a MySQL LIMIT exceeds the rows returned, this has no effect, so by setting this to a maximal value, it will always exceed the rows returned and/or the rows usable by the resulting page output.
Therefore:
$var = __getalldata("table",[0=>'columnname'],'id','desc',PHP_INT_MAX,'result');
Will return you every row within the PHP Integer limit of [2,147,483,647] or [9,223,372,036,854,775,807], depending on your system (32bit or 64bit).
And let's face it -- if 2 billion is not enough of a limit, you need to face you have some serious problems with your SQL query ;-)

Answer 6

That is easy with the use of an if statement. Just check to see if a condition is true for your limit, if not resolve to else. Like so:
public function __getalldata($tablename,$tablefield=array(),$orderbyfield = 'id',$ascdesc = 'desc',$limit = 200,$type='result')
{
if () // check $limit condition here
{
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->limit($limit)
->get();
return $data->$type();
}
else {
$data = $this->db
->select($tablefield)
->from($tablename)
->order_by($orderbyfield, $ascdesc)
->get();
return $data->$type();
}
}
EDIT: I am not sure what your conditions for the $limit variable are, so just enter them in the if statement's arguments.