项目实训 2 设计ER图

1.ER图：

erDiagram
demand_form ||--o{ plan : distributes
process ||--o| material_application : applies
plan ||..|{ process : does
material_application{
    int id
    varchar no
    int material_id
    int expected_quantity
    int exported_quantity
    datetime export_finish_time
    int process_id
}
demand_form{
    int id
    varchar no
    int product_id
    int quantity
    date expected_date
    int original_demand_form_id
    datetime read_time
    bit waiting
}
plan{
    int	id
    varchar no
    int demand_form_id
    int expected_quantity
    datetime distribute_time
    int production_line_id
}
process{
    int id
    varchar no
    int plan_id
    varchar step
    datetime material_arrive_time
    int demand_quantity
    int produced_quantity
    datetime finish_time
}