I'm learning from an online course MySQL using the WampServer and editing code in MySQL Workbench. Trying to create a table with the following code, the column nome appears to be the primary key from the table, but i'm only…
Let's say I have the following two postgres tables with the same field: CREATE TABLE table1 ( label VARCHAR(50) ); CREATE TABLE table2 ( label VARCHAR(50) ); I want label to be unique across both tables. That is, the following…
I'm creating a database using MySQL for a music streaming application for my school project. It has a table "song_discoveries" which has these columns: user_id, song_id and discovery_date. It has no primary key. The "user_id" and "song_id" are foreign keys…
So I just started learning SQL online and while learning about constraints, below example was given for using DEFAULT constraint: CREATE TABLE persons( ID INT NULL DEFAULT 100, f_name VARCHAR(25), l_name VCARCHAR(25), UNIQUE(ID) ); My question is, if ID is…