{
  "area_monthly_metrics": {
    "description": "Monthly area-level housing market metrics.",
    "target_table": "silver.area_monthly_metrics",
    "primary_key": ["area_id", "month"],
    "columns": [
      {
        "name": "area_id",
        "type": "text",
        "required": true,
        "description": "Stable area identifier from silver.areas."
      },
      {
        "name": "month",
        "type": "month",
        "required": true,
        "description": "Metric month in YYYY-MM format."
      },
      {
        "name": "transaction_count",
        "type": "integer",
        "required": true,
        "min": 0,
        "description": "Observed second-hand transaction count."
      },
      {
        "name": "transaction_price_psm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Average transaction price, RMB per square meter."
      },
      {
        "name": "listing_count",
        "type": "integer",
        "required": true,
        "min": 0,
        "description": "Active listing count."
      },
      {
        "name": "listing_price_psm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Average listing price, RMB per square meter."
      },
      {
        "name": "median_days_on_market",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Median days on market."
      },
      {
        "name": "rent_price_psm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Monthly rent, RMB per square meter."
      },
      {
        "name": "new_supply_units",
        "type": "integer",
        "required": true,
        "min": 0,
        "description": "New residential supply units."
      },
      {
        "name": "land_residential_gfa_sqm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Residential land transaction GFA, square meters."
      },
      {
        "name": "mortgage_rate_pct",
        "type": "decimal",
        "required": true,
        "min": 0,
        "max": 20,
        "description": "Mainstream mortgage rate percentage."
      },
      {
        "name": "policy_signal",
        "type": "integer",
        "required": true,
        "min": -2,
        "max": 2,
        "description": "Policy direction signal from -2 to 2."
      },
      {
        "name": "source",
        "type": "text",
        "required": true,
        "description": "Human-readable source name or source code."
      }
    ]
  },
  "neighborhood_monthly_metrics": {
    "description": "Monthly neighborhood-level housing market metrics.",
    "target_table": "silver.neighborhood_monthly_metrics",
    "primary_key": ["neighborhood_id", "month"],
    "columns": [
      {
        "name": "neighborhood_id",
        "type": "text",
        "required": true,
        "description": "Stable neighborhood identifier from silver.neighborhoods."
      },
      {
        "name": "month",
        "type": "month",
        "required": true,
        "description": "Metric month in YYYY-MM format."
      },
      {
        "name": "transaction_count",
        "type": "integer",
        "required": true,
        "min": 0,
        "description": "Observed transaction count."
      },
      {
        "name": "transaction_price_psm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Average transaction price, RMB per square meter."
      },
      {
        "name": "listing_count",
        "type": "integer",
        "required": true,
        "min": 0,
        "description": "Active listing count."
      },
      {
        "name": "listing_price_psm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Average listing price, RMB per square meter."
      },
      {
        "name": "rent_price_psm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Monthly rent, RMB per square meter."
      },
      {
        "name": "median_days_on_market",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Median days on market."
      },
      {
        "name": "available_units",
        "type": "integer",
        "required": true,
        "min": 0,
        "description": "Currently available units in the neighborhood sample."
      },
      {
        "name": "source",
        "type": "text",
        "required": true,
        "description": "Human-readable source name or source code."
      }
    ]
  },
  "policy_events": {
    "description": "Policy events that can affect market liquidity, credit or demand.",
    "target_table": "raw.policy_events",
    "primary_key": ["event_date", "title"],
    "columns": [
      {
        "name": "event_date",
        "type": "date",
        "required": true,
        "description": "Policy event date in YYYY-MM-DD format."
      },
      {
        "name": "level",
        "type": "enum",
        "required": true,
        "allowed_values": ["national", "shanghai", "district"],
        "description": "Policy jurisdiction level."
      },
      {
        "name": "title",
        "type": "text",
        "required": true,
        "description": "Short policy title."
      },
      {
        "name": "impact_direction",
        "type": "integer",
        "required": true,
        "min": -2,
        "max": 2,
        "description": "Expected impact from -2 tightening to 2 easing."
      },
      {
        "name": "notes",
        "type": "text",
        "required": false,
        "description": "Analyst notes and interpretation."
      },
      {
        "name": "source_url",
        "type": "url",
        "required": false,
        "description": "Official notice or source URL."
      },
      {
        "name": "source",
        "type": "text",
        "required": true,
        "description": "Human-readable source name or source code."
      }
    ]
  },
  "land_sales": {
    "description": "Residential land transaction records used for supply pressure analysis.",
    "target_table": "raw.land_sales",
    "primary_key": ["parcel_id"],
    "columns": [
      {
        "name": "parcel_id",
        "type": "text",
        "required": true,
        "description": "Stable land parcel identifier from the source."
      },
      {
        "name": "area_id",
        "type": "text",
        "required": true,
        "description": "Mapped area identifier from silver.areas."
      },
      {
        "name": "transaction_date",
        "type": "date",
        "required": true,
        "description": "Land transaction date in YYYY-MM-DD format."
      },
      {
        "name": "parcel_name",
        "type": "text",
        "required": true,
        "description": "Land parcel name."
      },
      {
        "name": "residential_gfa_sqm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Residential planned gross floor area, square meters."
      },
      {
        "name": "transaction_price_total_cny",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Total transaction price in RMB."
      },
      {
        "name": "floor_price_cny_psm",
        "type": "decimal",
        "required": true,
        "min": 0,
        "description": "Implied floor price, RMB per square meter."
      },
      {
        "name": "buyer",
        "type": "text",
        "required": false,
        "description": "Winning bidder or buyer."
      },
      {
        "name": "source_url",
        "type": "url",
        "required": false,
        "description": "Announcement or source URL."
      },
      {
        "name": "source",
        "type": "text",
        "required": true,
        "description": "Human-readable source name or source code."
      }
    ]
  }
}