how to validate id and ensure that is found in another table before inserting data using SQL

Question

I have three tables first table for articles

id	content
1	dummy content_1
2	dummy content_2
3	dummy content_3
4	dummy content_4
5	dummy content_5

and another for categories

id	category_name	slug
1	movies	movies
2	men health	men-health
3	tech	tech
4	games	games
5	food	food

and third table for defining categories for each article

article_id	category_id
1	5
2	5
2	1
2	3
3	5
3	1

and i am using normal insert statement to insert data into third table and while inserting the IDs into the third table i want to validate if they found in first and second table i.e if i am inserting the following row

article_id	category_id
3	1

i want to check if there is article id 3 and there is category id 1 in one query and if one of them not found cancel the insertion process how i write a query for this ?

Answer 1

first of all make the id column primary key on each tables categories and articles

ALTER TABLE categories
ADD PRIMARY KEY (ID);

ALTER TABLE articles
ADD PRIMARY KEY (ID);

just add a foreign key constraint for the two columns

ALTER TABLE article_category
ADD FOREIGN KEY (category_id) REFERENCES categories(id);

ALTER TABLE article_category
ADD FOREIGN KEY (article_id) REFERENCES articles(id);