/**
* Code below was lifted from Solar_Sql_Model_Record::isChanged($col=null)
*
* Tells if a particular table-column has changed.
*
* This is slightly complicated. Changes to or from a null are reported
* as "changed". If both the initial value and new value are numeric
* (that is, whether they are string/float/int), they are compared using
* normal inequality (!=). Otherwise, the initial value and new value
* are compared using strict inequality (!==).
*
* This complexity results from converting string and numeric values in
* and out of the database. Coming from the database, a string numeric
* '1' might be filtered to an integer 1 at some point, making it look
* like the value was changed when in practice it has not.
*
* Similarly, we need to make allowances for nulls, because a non-numeric
* null is loosely equal to zero or an empty string.
*
* @param string $col The table-column name.
*
* @return void|bool Returns null if the table-column name does not exist,
* boolean true if the data is changed, boolean false if not changed.
*
* @todo How to handle changes to array values?
*
*/
public function isChanged($col = null)
{
// if no column specified, check if the record as a whole has changed
if ($col === null) {
$cols = $this->_model->getTableColNames();
foreach ($cols as $col) {
if ($this->isChanged($col)) {
return true;
}
}
return false;
}
// col needs to exist in the initial array
if (!array_key_exists($col, $this->_initial_data) && array_key_exists($col, $this->_data) || array_key_exists($col, $this->_initial_data) && !array_key_exists($col, $this->_data)) {
return true;
} else {
if (!array_key_exists($col, $this->_initial_data) && !array_key_exists($col, $this->_data)) {
return null;
} else {
// array_key_exists($col, $this->_initial_data)
// && array_key_exists($col, $this->_data)
// track changes to or from null
$from_null = $this->_initial_data[$col] === null && $this->_data[$col] !== null;
$to_null = $this->_initial_data[$col] !== null && $this->_data[$col] === null;
if ($from_null || $to_null) {
return true;
}
// track numeric changes
$both_numeric = is_numeric($this->_initial_data[$col]) && is_numeric($this->_data[$col]);
if ($both_numeric) {
// use normal inequality
return $this->_initial_data[$col] != (string) $this->_data[$col];
}
// use strict inequality
return $this->_initial_data[$col] !== $this->_data[$col];
}
}
}
