how to change category_shop.position by script?

[IgnacioSM]

Hello,

 

I'm trying to receive the position of the categories by another software, and then, I have to update the category position, or insert the category.

 

 

how could I insert a category in a position and increment the position of the others if there are some duplicate positions? 

 

 

Ex: I want to insert a new category in position 3, and mofify th$cat = new Category($idClasificacionOnline);

 

 

Code:

$cat-id_parent = $idClasFather;

Category::cleanPositions($idClasFather);

$cat->addPosition(3, $idShop);

 

It eliminates all the duplicates, but it left a category with position 3(obviously) and then, it inserts the new category with position 3. Finally, the result is that there are two categories with position 3.

 

Any idea?

Edited February 12, 2015 by IgnacioSM (see edit history)