I have a function for getting path in a tree structure data.
According to my table in DB, root should get no result when I query sub_id='root_id'
When I just pass the root the rowCount return correct result which is 0. However when I pass a node from lower rank[3rd], in the end of the recursive which is root, rowCount return 1?
PS
I use Mysql as DB
This is my table
main_id | sub_id
----------------
1 | 2
1 | 3
2 | 4
3 | 5
The code:
$stmt = $conn->prepare["Select * from table where sub_id= ? "];
function get_path[$stmt,$node,&$map]{
$res=$stmt->execute[array[$node]];
if[!$res]{ throw new Exception[ implode[' ',$stmt->errorInfo[]],1]; }
echo $node.' found '.$stmt->rowCount[].'
';
if[$stmt->rowCount[]==0]{ //root
$map[]=$node;
}else{
foreach[$stmt->fetchAll[PDO::FETCH_ASSOC] AS $row]{
$map[]=$node;
$upper_node=$row['main_id'];
get_path[$stmt,$upper_node,$map];
}
}
}
If I just pass get_path[$stmt,1,$map];
[the root]
the output:
1 found 0
but when I for example pass 4 into it the output become:
4 found 1
2 found 1
1 found 1 = 5.1.0, PHP 7, PHP 8, PECL pdo >= 0.1.0]PDOStatement::rowCount — Returns the number of rows affected by the last SQL statement
Description
public PDOStatement::rowCount[]: int
If the last SQL statement executed by the associated PDOStatement was a SELECT
statement, some databases may return the number of rows returned by that statement. However, this behaviour is not guaranteed for all databases and should not be relied on for portable applications.
Note:
This method returns "0" [zero] with the SQLite driver at all times, and with the PostgreSQL driver only when setting the PDO::ATTR_CURSOR statement attribute to PDO::CURSOR_SCROLL.
Parameters
This function has no parameters.
Return Values
Returns the number of rows.
Examples
Example #1 Return the number of deleted rows
PDOStatement::rowCount[] returns the number of rows affected by a DELETE,
INSERT, or UPDATE statement.
The above example will output something similar to:
Return number of rows that were deleted:
Deleted 9 rows.
Example #2 Counting rows returned by a SELECT statement
For most databases, PDOStatement::rowCount[] does not return the number of rows affected by a SELECT statement. Instead, use
PDO::query[] to issue a SELECT COUNT[*] statement with the same predicates as your intended SELECT statement, then use PDOStatement::fetchColumn[] to retrieve the number of matching rows.