Well, the insertion has failed, because the database keeps track of what is being added. If it finds out that the combination which constitutes the primary key has already been used, your instruction will be rejected.
Let's see if you can create a new table based on the description below:
Each customer in our store has certain favorite genres. As such, we need a table named preference consisting of the following information:
user_id (an integer).priority (an integer).genre (text of up to 20 characters).The first two columns form the primary key.
We created a simple template for you. Fill in the gaps with the table name, column names, and column types!
Type:
CREATE TABLE preference ( user_id integer, priority integer, genre varchar(20), PRIMARY KEY (user_id, priority) );
