Participation Constraints in SQL

We can capture participation constraints involving one entity set in a binary relationship, but little else (without resorting to CHECK constraints).

CREATE TABLE Dept_Mgr(

did INTEGER,

dname CHAR(20),

budget REAL,

ssn CHAR(11) NOT NULL,

since DATE,

PRIMARY KEY (did),

FOREIGN KEY (ssn) REFERENCES Employees,

ON DELETE NO ACTION)

We can capture participation constraints involving one entity set in a binary relationship, but little else (without resorting to CHECK constraints).