I've a question regarding Oracle database SQL.

my employee each have a project, the end date of the project depends on the no of months that was given to them base on PTerm. Am i right to do it this way?

CREATE TABLE PROJECT ( P_ID VARCHAR ( 20 ) NOT NULL,
                   PNAME VARCHAR ( 100 ) NOT NULL,
                   PTERM VARCHAR ( 20 ),
                   PSTARTDATE DATE,
                   PENDDATE DATE,
                   CONSTRAINT PROJECT_PKEY PRIMARY KEY ( P_ID ),
                   CONSTRAINT PROJECT_PTERM CHECK
                       ( PTERM IN ('1 MONTH', '2 MONTH', '3 MONTH') ),
                   CONSTRAINT PROJECT_ENDDATE CHECK
                       ( PENDDATE = (PSTARTDATE + PTERM) ) );