Consider the following entities and their relationship. create a rdb in 4 nf with appropriate data types and constraints. emp(eno,ename,designation, salary,date of joining) the relationship between de

consider the following entities and their relationship. create a rdb in 4 nf with appropriate data types and constraints. emp(eno,ename,designation, salary,date of joining) the relationship between dept and emp is one-to-many. constrains: primary key, ename should not be null, salary must be greater than o. consider the above tables and execute the following queries. 1)add column phone_no into emp table with data type int. 2) delete the details of employees whose designation is ' manager'.