Apply the following validations before inserting the record into the database.

$1.$ EmpNo: must contain only digits and the maximum number of digits is $7$

$2.$ Name : must contain only alphabets and at least $3$ alphabtes

$3.$ Salary : must contain only digits and the maximum number of digits is $4$

$4.$ Address: may contain alphabets and digits.

$5.$ Dept No : the values of this field may only be $10$ or $20$