Consider the two relations with their schemas as listed below: Employee(name, empID, birthDate, gender, address, phone) TaxAccount(name, SSN, empID, federalDeductionAmt, stateDeductionAmt, ficaDeductionAmt) Constraint: TaxAccount must contain information related to all current employees only. Express the foreign key constraint in SQL.

CREATE TABLE TaxAccount (

Name int NOT NULL,

SSN int NOT NULL,

empID int FOREIGN KEY REFERENCES employee(empID),

federalDeductionAmt int NOT NULL,

stateDeductionAmt int NOT NULL,

ficaDeductionAmt int NOT NULL

);

Explanation:

TaxAccount table will use the primary key of employees table 'empID' which will serve as foreign key in TaxAccount table.

Therefore TaxAccount table will look like this:

CREATE TABLE TaxAccount (

Name int NOT NULL,

SSN int NOT NULL,

empID int FOREIGN KEY REFERENCES employee(empID),

federalDeductionAmt int NOT NULL,

stateDeductionAmt int NOT NULL,

ficaDeductionAmt int NOT NULL

);

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.