please answer questions 1-6 provide SQL statement only

Use the operator and/or statement asked. Otherwise, you will have zero (0) point for the question. 1. Change the Salary column in the Employee table to reject nulls. 2. Change the length of the CITY column in the Employee table to 50 characters. 3. Change the department name in the Department table to Administration for the department name entitled Admin and Records Add a department in the Department table. You choose the data for the new department Delete the new department you added in #4. Add foreign key constraints to Assignment table. 4. 6