## Real_Estate_Developer

id | name | contact_info
--- | --- | ---
1 | Company A | +123456789
2 | Company B | +987654321

## Contractor

id | name | specialty | license_number
--- | --- | --- | ---
1 | Contractor X | Concrete Work | LX001
2 | Contractor Y | Plumbing | LY002

## Development_Project

id | project_name | developer_id | contractor_id
--- | --- | --- | ---
|  | (→ Real_Estate_Developer.id) | (→ Contractor.id)
1 | High Rise Building | 1 | 1
2 | Residential Complex | 2 | 2

## Project_Milestone

id | milestone_description | start_date | end_date | development_project_id
--- | --- | --- | --- | ---
|  |  |  | (→ Development_Project.id)
1 | Foundation Completed | 2023-01-01 | 2023-01-10 | 1
2 | Framing Started | 2023-01-11 | 2023-01-20 | 1

## Materials

id | material_type | quantity | unit_price | contractor_id
--- | --- | --- | --- | ---
|  |  |  | (→ Contractor.id)
1 | Reinforcement Bar | 500 | 10 | 1
2 | Pipes | 300 | 8 | 2

## Employee

id | first_name | last_name | position | contractor_id
--- | --- | --- | --- | ---
|  |  |  | (→ Contractor.id)
1 | John | Smith | Site Supervisor | 1
2 | Jane | Doe | Engineer | 2