Proper way to store all days of every month in database

I want to store such fields in the table as: the ID of the employee, his last name and first name, and how many hours he worked on each day of the month. For example, March 1 – 6 hours, March 2 – 4 hours, March 3 – 4 hours. The example I gave in the table below is how I imagine it, is there a way to store this data in a more convenient way to do it in PostgreSQL? And how to handle the situation when there are 30, 31, 28, or 29 days in the month?

>Solution :

All you need is:

CREATE TABLE PersonsWorkedHours (
    PersonId int  NOT NULL,
    Date     date NOT NULL,
    Hours    real NOT NULL,
    
    CONSTRAINT PK_PersonsWorkedHours PRIMARY KEY ( PersonId, Date ), /* This composite PK ensures that PersonId+Date is always unique, so the same Person cannot have 2 or more rows with the same Date value */
    CONSTRAINT FK_Hours_to_People    FOREIGN KEY ( PersonId ) REFERENCES People ( PersonId ),
    CONSTRAINT UK_PersonsWorkedHours UNIQUE KEY  ( Date, PersonId ), /* this is a secondary-key for the benefit of Date-first queries, instead of PersonId-first queries. */

    CONSTRAINT CK_HoursPerDay CHECK ( Hours >= 0 AND Hours < 24 ),
    
    INDEX FX_People ( PersonId )
)

And how to handle the situation when there are 30, 31, 28, or 29 days in the month?

You don’t need to handle it: the date type handles this for you.