Here is the pseudo code:

var relations = relationRepository.GetParents<NodeEntryRelation>(productLink).ToList();

foreach (var categoryLink in categoryLinks)

{

 var relationToRemove = relations.FirstOrDefault(x=>x.Parent == categoryLink);

if (relationToRemove != null)

relations.Remove(relationToRemove);

}

relationRepository.UpdateRelations(relations);

Thanks @Quan Mai for taking time out and answering.

I am not abel to reach remove association.

The problem is is "categoryLinks". They always come 0.

To remove association, I need to have categoryContentReference but that is not returned.

var productContentLink = this.referenceConverter.GetContentLink(productCode, CatalogContentType.CatalogEntry);
            IList<ContentReference> categoryRefrences = new List<ContentReference>();

            var categories = this.contentLoader.GetChildren<CategoryNode>(productContentLink);

            // THE ABOVE ALWAYS HAVE COUNT 0

The problematic line is this  var categories = this.contentLoader.GetChildren<CategoryNode>(productContentLink);

You can't get children of a product. If you want to replace  the existing parents of a product, just do this

var relations = new List<NodeEntryRelation>();

//add relations from your CSV to relations

Hi Shaan,

Try the below code and replaced 'FashionProduct' with '[Your Product Type]' for retrieving the product categories.

      private IList<ContentReference> GetCategories(string productCode)
        {
            var contentLink = _referenceConverter.GetContentLink(productCode, CatalogContentType.CatalogEntry);
            var productContentLink = _contentLoader.Get<FashionProduct>(contentLink);

            var contentBase = productContentLink as EntryContentBase;
            var categories = this.GetCategoriesAll(contentBase).ToList();

            IList<ContentReference> categoryReferences = new List<ContentReference>();
            foreach (var category in categories)
            {
                System.Diagnostics.Debug.WriteLine(category.Name + ": " + category.ContentLink);
                categoryReferences.Add(category.ContentLink);
            }

            return categoryReferences;
        }

        private IEnumerable<NodeContent> GetCategoriesAll(EntryContentBase child)
        {
            var list = new List<NodeContent>();

            if (child != null)
            {
                var parentLinks = child.GetCategories(_relationRepository);

                foreach (var parentLink in parentLinks)
                {
                    if (!_contentLoader.TryGet(parentLink, out NodeContent parent))
                        continue;

                    list.Add(parent);
                    list.AddRange(this.GetCategoriesAll(parent));
                }
            }

            return list;
        }

        private IEnumerable<NodeContent> GetCategoriesAll(NodeContent child)
        {
            var list = new List<NodeContent>();

            if (child != null)
            {
                var parentLinks = child.GetCategories(_relationRepository);

                foreach (var parentLink in parentLinks)
                {
                    if (!_contentLoader.TryGet(parentLink, out NodeContent parent))
                        continue;

                    list.Add(parent);
                    list.AddRange(this.GetCategoriesAll(parent));
                }
            }

            return list;
        }