Assume that the takes relation has not yet been defined. Give an SQL statement that adds the takes relation to the database.

Assume that:

Id is an integer

course_id is a string of up to10 characters.

sec_id should be a non-negative integer.

the semester is a one-character field, equal to either F or S, and the

year is an integer.

grade can be null, but if not, it should be a letter in the string ABCDF.

Your statement must ensure that no attributes, other than the grade, are allowed to be null in this relation, identify a suitable primary key, and indicate appropriate foreign key(s). Include not null constraints only on attributes where the domain is not already constrained to exclude nulls.

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student takes ID course_id sec_id semester year name dept_name tot_cred grade section advisor course id sec_id course course_id title dept_name credits semester department dept_name building budget Slid i id year building room_no time_slot_id time_slot time slot_id day start_time end_time instructor classroom building room_no capacity prereq course_id prereg_id ID name dept_name salary teaches course_id sec_id semester year