Table: farm

Description (EN): This table represents agricultural enterprises. In the database's inheritance architecture, it acts as a direct sub-type of the enterprise table. It does not store redundant descriptive columns; instead, it uses a shared primary key to inherit all high-level attributes (such as name, location, management type, and geometry) from its parent enterprise record.

Column Structure

Column	Data type	Definition	Example value	Constraint?	Geometry?	Comments
id	BIGINT	Unique identifier for the farm	42	PK, FK	No	Primary key that also acts as a Foreign Key referencing enterprise.id

Relationships

• Inherits from (Sub-type of): enterprise. The farm table is a specialized extension of the enterprise table.
• Contains: While not linked directly via a farm_id, a farm owns agricultural assets through the enterprise_id column in the component table. These components often include specialized agricultural sub-types such as:
  • crop
  • livestock
  • agriculture_product
  • structure (e.g., barns, greenhouses)
  • machinery (e.g., tractors)

!!! tip "Where is the rest of the data?" To find the name, geographical location (geometry, town, country), or ownership details of a farm, you must join this table with the enterprise record that shares the exact same id.

Example Query

Retrieve a list of all farms, including their names, towns, and spatial coordinates, by joining the table with its parent enterprise entity:

SELECT 
    f.id, 
    e.name, 
    e.town, 
    ST_AsText(e.geometry) as coordinates 
FROM 
    farm f
JOIN 
    enterprise e ON f.id = e.id
WHERE 
    e.type = 'FARM';