![]() ![]() PRIMARY KEY (user_id, role_id) Code language: SQL (Structured Query Language) ( sql )īecause the user_idcolumn references to the user_idcolumn in the accounts table, we need to define a foreign key constraint for the user_idcolumn: FOREIGN KEY (user_id) The primary key of the account_roles table consists of two columns: user_id and role_id, therefore, we have to define the primary key constraint as a table constraint. The following statement creates the account_roles table that has three columns: user_id, role_id and grant_date. The following statement creates the roles table that consists of two columns: role_id and role_name: CREATE TABLE roles( ![]() The following statement creates the accounts table: CREATE TABLE accounts ( We will create a new table called accounts that has the following columns: Table constraints are similar to column constraints except that they are applied to more than one column. Unlike the primary key, a table can have many foreign keys.
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