Sorry for newbie question.

For example, there is some kind of abstract device, we will call the Device class and the tasks for it: Task1, Task2, Task3. For concreteness, I will describe everything in java codes.

class Device { long id; String name; int ip; int filed1; String filed2; // and so on }  class Task1 { long id; long device_id; // id from Device class int type = 1; int property1; int property2; int property3; // Properties and their number are completely different in all Task, that is, the tasks are completely different. }  class Task2 { long id; long device_id; // id from Device class int type = 2; int anotherProperty1; int anotherProperty2; int anotherProperty3; int anotherProperty4; int anotherProperty5; int anotherProperty6; // Properties and their number are completely different in all Task, that is, the tasks are completely different. }  class Task3 { long id; long device_id; // id from Device class int type = 3; int yetAnotherProperty1; int yetAnotherProperty2; // Properties and their number are completely different in all Task, that is, the tasks are completely different. } 

Further, for each device a certain number of tasks are assigned, both with different classes and with the same ones. For example.

// pseudocode Device device1 = new Device (.....); // The list of tasks for the device 1 (Any combination, any number) 1. new Task2 2. new Task2 3. new Task1 4. new Task3  Device device2 = new Device (.....); // The list of tasks for the device 2 (Any combination, any number) 1. new Task1 2. new Task3  Device device3 = new Device (.....); // The list of tasks for the device 3 (Any combination, any number) 1. new Task1 2. new Task3 3. new Task1 4. new Task3 5. new Task1 6. new Task3 7. new Task1 8. new Task3 9. new Task1 10. new Task3 // and so on 

I created the Device table with all the required fields, but I do not know how to save all this correctly in the database. I will assume that:

• is need to create more tables: Task1, Task2, Task3?

• (when saving) to the specific tables put the all tasks, Device.id which corresponds to Task.device_id and the order of their execution?

• (when load) do a query from all the tables Device, Task1, Task2, Task3 – and check from each task whether Device.id = Task1.device_id AND Device.id = Task2.device_id AND Device.id = Task3.device_id?

First, is the correct assumption, is the organization of the database structure correct or ….?

If yes, how correctly to do the optimized selection from several tables, write sql request if it is possible ..