Company DB

-----------------Create database-----------------------------------------------------
CREATE TABLE Employee
(   fname       VARCHAR(15) NOT NULL,
    minit       CHAR(1),                        -- The default of CHAR is also 1 byte
    lname       VARCHAR(15) NOT NULL,
    ssn         CHAR(9)     PRIMARY KEY,
    bdate       DATE,
    address     VARCHAR(30),
    sex         CHAR(1),
    salary      DECIMAL(10,2),
    superssn    CHAR(9),
    dno         INT         NOT NULL,
    CONSTRAINT  fk_emp_superssn FOREIGN KEY (superssn)
                REFERENCES Employee(ssn)
                ON DELETE SET NULL DEFERRABLE
);

CREATE TABLE Department
(   dname       VARCHAR(15) NOT NULL    UNIQUE,
    dnumber     INT         PRIMARY KEY,
    mgrssn      CHAR(9)     NOT NULL,
    mgrstartdate    DATE,
    CONSTRAINT  fk_dept_emp_mgrssn FOREIGN KEY (mgrssn)
                REFERENCES Employee(ssn)
                ON DELETE SET NULL  DEFERRABLE
);

ALTER TABLE Employee
ADD CONSTRAINT  fk_emp_dept_dno FOREIGN KEY (dno)
                REFERENCES Department(dnumber)
                ON DELETE SET NULL;

CREATE TABLE Dept_locations
(   dnumber     INT         NOT NULL,
    dlocation   VARCHAR(15) NOT NULL,
    PRIMARY KEY (dnumber, dlocation),
    CONSTRAINT  fk_loc_dept_dnum    FOREIGN KEY (dnumber)
                REFERENCES Department(dnumber)
                ON DELETE CASCADE
);

CREATE TABLE Project
(   pname       VARCHAR(15) NOT NULL    UNIQUE,
    pnumber     INT         PRIMARY KEY,
    plocation   VARCHAR(15),
    dnum        INT         NOT NULL,
    CONSTRAINT  fk_proj_dept_dnum   FOREIGN KEY (dnum)
                REFERENCES Department(dnumber)
                ON DELETE SET NULL
);

CREATE TABLE    Works_on
(   essn        CHAR(9)     NOT NULL,
    pno         INT         NOT NULL,
    hours       DECIMAL(3,1)    NOT NULL,
    PRIMARY KEY (essn, pno),
    CONSTRAINT  fk_work_emp_essn    FOREIGN KEY (essn)
                REFERENCES Employee(ssn)
                ON DELETE CASCADE,
    CONSTRAINT  fk_work_proj_pno    FOREIGN KEY (pno)
                REFERENCES Project(pnumber)
                ON DELETE CASCADE
);

ALTER TABLE works_on
MODIFY hours    DECIMAL(3,1)    NULL;

CREATE TABLE Dependent
(   essn            CHAR(9)     NOT NULL,
    dependent_name  VARCHAR(15) NOT NULL,
    sex             CHAR,
    bdate           DATE,
    relationship    VARCHAR(8),
    PRIMARY KEY (essn, dependent_name),
    CONSTRAINT  fk_depend_emp_essn  FOREIGN KEY (essn)
                REFERENCES Employee(ssn)
                ON DELETE CASCADE
);

-------------------------Insert data-----------------------------------------------------------------------------------------------------
SET CONSTRAINTS fk_dept_emp_mgrssn  DEFERRED;
SET CONSTRAINTS fk_emp_superssn  DEFERRED;

ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MM-YYYY';

INSERT INTO Department VALUES ('Research', 5, '333445555', '22-05-1988');
INSERT INTO Department VALUES ('Administration', 4, '987654321', '01-01-1995');
INSERT INTO Department VALUES ('Headquarters', 1, '888665555', '19-06-1981');

INSERT INTO Employee VALUES ('John', 'B', 'Smith', '123456789', '09-01-1965', '731 Fondren, Houston, TX', 'M', 30000, '333445555', 5);
INSERT INTO Employee VALUES ('Franklin', 'T', 'Wong', '333445555', '08-12-1955', '638 Voss, Houston, TX', 'M', 40000, '888665555', 5);
INSERT INTO Employee VALUES ('Alicia', 'J', 'Zelaya', '999887777', '19-07-1968', '3321 Castle, Spring, TX', 'F', 25000, '987654321', 4);
INSERT INTO Employee VALUES ('Jennifer', 'S', 'Wallace', '987654321', '20-06-1941', '291 Berry, Bellaire, TX', 'F', 43000, '888665555', 4);
INSERT INTO Employee VALUES ('Ramesh', 'K', 'Narayan', '666884444', '15-09-1962', '975 Fire Oak, Humble, TX', 'M', 38000, '333445555', 5);
INSERT INTO Employee VALUES ('Joyce', 'A', 'English', '453453453', '31-07-1972', '5631 Rice, Houston, TX', 'F', 25000, '333445555', 5);
INSERT INTO Employee VALUES ('Ahmad', 'V', 'Jabbar', '987987987', '29-03-1969', '980 Dallas, Houston, TX', 'M', 25000, '987654321', 4);
INSERT INTO Employee VALUES ('James', 'E', 'Borg', '888665555', '10-11-1973', '450 Stone, Houston, TX', 'M', 55000, NULL, 1);

COMMIT;
ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MM-YYYY';

INSERT INTO Dept_locations VALUES (1, 'Houston');
INSERT INTO Dept_locations VALUES (4, 'Stafford');
INSERT INTO Dept_locations VALUES (5, 'Bellaire');
INSERT INTO Dept_locations VALUES (5, 'Sugarland');
INSERT INTO Dept_locations VALUES (5, 'Houston');

INSERT INTO Project VALUES ('ProductX', 1, 'Bellaire', 5);
INSERT INTO Project VALUES ('ProductY', 2, 'Sugarland', 5);
INSERT INTO Project VALUES ('ProductZ', 3, 'Houston', 5);
INSERT INTO Project VALUES ('Computerization', 10, 'Stafford', 4);
INSERT INTO Project VALUES ('Reorganization', 20, 'Houston', 1);
INSERT INTO Project VALUES ('Newbenefits', 30, 'Stafford', 4);

INSERT INTO Works_on VALUES ('123456789', 1, 32.5);
INSERT INTO Works_on VALUES ('123456789', 2, 7.5);
INSERT INTO Works_on VALUES ('666884444', 3, 40.0);
INSERT INTO Works_on VALUES ('453453453', 1, 20.0);
INSERT INTO Works_on VALUES ('453453453', 2, 20.0);
INSERT INTO Works_on VALUES ('333445555', 2, 10.0);
INSERT INTO Works_on VALUES ('333445555', 3, 10.0);
INSERT INTO Works_on VALUES ('333445555', 10, 10.0);
INSERT INTO Works_on VALUES ('333445555', 20, 10.0);
INSERT INTO Works_on VALUES ('999887777', 30, 30.0);
INSERT INTO Works_on VALUES ('999887777', 10, 10.0);
INSERT INTO Works_on VALUES ('987987987', 10, 35.0);
INSERT INTO Works_on VALUES ('987987987', 30, 5.0);
INSERT INTO Works_on VALUES ('987654321', 30, 20.0);
INSERT INTO Works_on VALUES ('987654321', 20, 15.0);
INSERT INTO Works_on VALUES ('888665555', 20, NULL);

INSERT INTO Dependent VALUES ('333445555', 'Alice', 'F', '05-04-1986', 'Daughter');
INSERT INTO Dependent VALUES ('333445555', 'Theodore', 'M', '25-10-1983', 'Son');
INSERT INTO Dependent VALUES ('333445555', 'Joy', 'F', '03-05-1958', 'Spouse');
INSERT INTO Dependent VALUES ('987654321', 'Abner', 'M', '28-02-1942', 'Spouse');
INSERT INTO Dependent VALUES ('123456789', 'Michael', 'M', '04-01-1988', 'Son');
INSERT INTO Dependent VALUES ('123456789', 'Alice', 'M', '04-01-1988', 'Son');
INSERT INTO Dependent VALUES ('123456789', 'Elizabeth', 'M', '05-05-1967', 'Spouse');