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Asked: 2026-05-14T21:41:22+00:00

I have a table, department , with several bit fields to indicate department types

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I have a table, department , with several bit fields to indicate department types
One is Warehouse (when true, indicate the department is warehouse)

And I have another table, ManagersForWarehouses with following structure:

ID autoinc
WarehouseID int (foreign key reference DepartmentID from departments)
ManagerID int (foreign key reference EmployeeID from employees)
StartDate
EndDate

To set new manager for warehouse, I insert in this table with EndDate null, and I have a trigger that sets EndDate for previous record for that warehouse = StartDate for new manager, so a single manager appears for a warehouse at a certain time.

I want to add two check constraints as follows, but not sure how to do this

  1. do not allow to insert into ManagersForWarehouses if WarehouseID is not marked as warehouse
  2. Do not allow to uncheck Warehouse if there are records in ManagersForWarehouses

Thanks

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1 Answer

  1. Editorial Team
    1. In Departments table, add a unique constraint (DepartmentID, IsWarehouse)
    2. In ManagersForWarehouses table, add column IsWarehouse, and have a CHECK constraint enforce that IsWarehouse=’Y’
    3. In ManagersForWarehouses table, add a FK on (WarehouseID , IsWarehouse) referrring to Departments(DepartmentID, IsWarehouse), and with ON UPDATE CASCADE clause.

    And you are all set with 100% rock solid integrity, without any loopholes. Only trusted constraints do not have any loopholes. Triggers are less reliable.

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