Question

I need to add article to multiple category
for example I have article name ‘test article’ need to add it to category 1 and category2
need to know how to make relationship between to tables for this

note : in the past I make row in article database table name ‘category’ and add category id like 1,2,3 but this make problem in search and list please help me about that

Answer 1

You need three tables:

• One table for articles
• One table for categories
• One table linking articles to categories, we might call it categories_per_article. This table often is called a Junction table or a Association table.

Example data:

ARTICLES
ID | Name | Description
1  | Fuzz | A fuzzy three
2  | Bizz | A five that means bizznezz

CATEGORIES
ID  |  Name 
1   |  Prime numbers
2   |  Multiples of five
3   |  Smaller than four

CATEGORIES_PER_ARTICLE
ID | ARTICLE_ID | CATEGORY_ID
1  | 1          | 1
2  | 1          | 2
3  | 1          | 3
4  | 2          | 1

You will see that article 1 (Fuzz) has three categories, and article 2 (Bizz) only has category 1. We call this a many-to-many relationship (or n-to-n, for example in ER or UML), because article 1 has multiple categories, and category 1 is used by multiple articles.

You can do all possible queries using this schema – feel free to ask in comments for specific examples (like How do I get all articles which have categories 1 and 3 but not 2).