If you want to store your extracted variable values in a database, you will have to create matching tables. Design Studio can assist you in creating these tables.
In the Tools menu, select 'Create Database Table' to open a window where you can choose the name of your database and the type(s) that you want to create table(s) for. By clicking 'Generate SQL', you will be shown a suggestion for an SQL statement for creating the table(s). By default the 'Add Drop Table' checkbox is checked, which ensures that each 'CREATE TABLE' statement is preceded by a 'DROP TABLE' statement to make sure the corresponding table is removed if it already exists. If a table does not exist, this statement simply has no effect.
You can change the generated SQL to fit your needs before you execute it. For example, you could change the column type for a text attribute from 'VARCHAR(255)' to 'VARCHAR(50)', or you could add an auto-incrementing primary key. However, normally, you should not change the table name or any of the column names, or remove any of the columns.