I am trying to re define my database design adding some extra tables so

Question

0

Asked: June 13, 20262026-06-13T22:29:39+00:00 2026-06-13T22:29:39+00:00

I am trying to re define my database design adding some extra tables so

0

I am trying to re define my database design adding some extra tables so There are no repeated names for example in my table Departaments and Jobs…

But I am getting the error 121 which has to do with foreign keys, can you explain why is this problem?

I am doing this in sqlfiddle

I am trying to do something like this but had no luck in sqlfiddle there is what i have working at the moment

 CREATE TABLE Employee(
          EmployeeID  INTEGER      NOT NULL PRIMARY KEY,
          Name        VARCHAR(30)  NOT NULL,
          Sex         CHAR(1)      NOT NULL,
          Address     VARCHAR(80)  NOT NULL,
          Security    VARCHAR(15)  NOT NULL          
        );

        CREATE TABLE Departments  (
            DeptID   INTEGER     NOT NULL PRIMARY KEY,
            DeptName VARCHAR(30) NOT NULL
        );

If I uncomment the code I get
Schema Creation Failed: Can’t create table ‘db_2_2bf4a.project-employee’ (errno: 121):

        CREATE TABLE `Dept-Employee`(
          EmployeeID   INTEGER NOT NULL,          
          DeptID       INTEGER NOT NULL,
          CONSTRAINT fk_DeptID     FOREIGN KEY (DeptID)  REFERENCES Departments(DeptID),
          CONSTRAINT fk_EmployeeID FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID)
        );

       CREATE TABLE `Dept-Manager`(
          EmployeeID   INTEGER NOT NULL,          
          DeptID       INTEGER NOT NULL,
          CONSTRAINT fk_DeptID     FOREIGN KEY (DeptID)  REFERENCES Departments(DeptID),
          CONSTRAINT fk_EmployeeID FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID)
        );

        CREATE TABLE Jobs (
            JobID            INTEGER      NOT NULL PRIMARY KEY,
            JobName          VARCHAR(30)  NOT NULL,
            JobSalary        DOUBLE(15,3) NOT NULL default '0.000', 
            JobSalaryperDay  DOUBLE(15,3) NOT NULL default '0.000', 
            DeptID           INTEGER      NOT NULL
        );

        CREATE TABLE `Jobs-Employee`(
          EmployeeID   INTEGER NOT NULL,
          JobID        INTEGER NOT NULL,
          CONSTRAINT fk_JobID      FOREIGN KEY (JobID)      REFERENCES Jobs(JobID),
          CONSTRAINT fk_EmployeeID FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID)
        );

        CREATE TABLE Project(
          ProjectID    INTEGER NOT NULL PRIMARY KEY,
          ProjectDesc   VARCHAR(200) NOT NULL,
          StartDate     DATE NOT NULL,
          EndDate       DATE NOT NULL, 
          DaysOfWork    INTEGER NOT NULL,
          NoEmployees   INTEGER NOT NULL,
          EstimatedCost DOUBLE(15,3) NOT NULL default '0.000', 
          RealCost      DOUBLE(15,3) NOT NULL default '0.000' 
        );


        CREATE TABLE `Project-Employee`(
          ProjectID    INTEGER NOT NULL,
          EmployeeID   INTEGER NOT NULL,
          Note         VARCHAR(200),
          DaysWork     INTEGER NOT NULL,
          CONSTRAINT fk_ProjectID  FOREIGN KEY (ProjectID)  REFERENCES Project(ProjectID),
          CONSTRAINT fk_EmployeeID FOREIGN KEY (EmployeeID) REFERENCES Employee(EmployeeID)
        );

So after I do not know if this queries would be correct

INSERT INTO `Departments` VALUES (1, 'Outsourcing');
    INSERT INTO `Departments` VALUES (2, 'Technician');
    INSERT INTO `Departments` VALUES (3, 'Administrative');

    INSERT INTO `Jobs` VALUES (1, 'welder'    ,500.550,16.7 ,2);
    INSERT INTO `Jobs` VALUES (2, 'turner'    ,500.100,16.67,2);
    INSERT INTO `Jobs` VALUES (3, 'assistant' ,650.100,21.67,2);
    INSERT INTO `Jobs` VALUES (4, 'supervisor',800.909,26.70,3);
    INSERT INTO `Jobs` VALUES (5, 'manager'   ,920.345,30.68,3);
    INSERT INTO `Jobs` VALUES (6, 'counter'   ,520.324,17.35,1);

    INSERT INTO `Dept-Employee` (10,1);
    INSERT INTO `Dept-Employee` (10,2);
    INSERT INTO `Dept-Employee` (10,3);
    INSERT INTO `Dept-Employee` (10,1);
    INSERT INTO `Dept-Employee` (10,3);

    INSERT INTO `Jobs-Employee` (10,3);
    INSERT INTO `Jobs-Employee` (10,3);
    INSERT INTO `Jobs-Employee` (10,4);
    INSERT INTO `Jobs-Employee` (10,6);
    INSERT INTO `Jobs-Employee` (10,5);

    INSERT INTO `Employee` VALUES (10, 'Joe',  'M', 'Anywhere', '927318344');
    INSERT INTO `Employee` VALUES (20, 'Moe',  'M', 'Anywhere', '827318322');
    INSERT INTO `Employee` VALUES (30, 'Jack', 'M', 'Anywhere', '927418343');
    INSERT INTO `Employee` VALUES (40, 'Marge','F', 'Evererre', '127347645');
    INSERT INTO `Employee` VALUES (50, 'Greg' ,'M', 'Portland', '134547633');


    INSERT INTO `Project` VALUES (1, 'The very first', '2008-7-04' , '2008-7-24' , 20, 5, 3000.50, 2500.00);
    INSERT INTO `Project` VALUES (2, 'Second one pro', '2008-8-01' , '2008-8-30' , 30, 5, 6000.40, 6100.40);


    INSERT INTO `Project-Employee` VALUES (1, 10, 'Worked all days'    , 20);
    INSERT INTO `Project-Employee` VALUES (1, 20, 'Worked just in defs', 11);
    INSERT INTO `Project-Employee` VALUES (1, 30, 'Worked just in defs', 17);
    INSERT INTO `Project-Employee` VALUES (1, 40, 'Contability '       , 8);
    INSERT INTO `Project-Employee` VALUES (1, 50, 'Managed the project', 8);