{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "ErdJson",
  "description": "JSON representation of the ERD",
  "type": "object",
  "properties": {
    "relationships": {
      "type": "array",
      "items": {
        "$ref": "#/$defs/RelationshipJson"
      }
    },
    "stats": {
      "$ref": "#/$defs/ErdStats"
    },
    "tables": {
      "type": "array",
      "items": {
        "$ref": "#/$defs/TableJson"
      }
    }
  },
  "required": ["tables", "relationships", "stats"],
  "$defs": {
    "ColumnJson": {
      "description": "JSON representation of a column",
      "type": "object",
      "properties": {
        "is_foreign_key": {
          "type": "boolean"
        },
        "is_nullable": {
          "type": "boolean"
        },
        "is_primary_key": {
          "type": "boolean"
        },
        "name": {
          "type": "string"
        },
        "references_column": {
          "type": ["string", "null"]
        },
        "references_table": {
          "type": ["string", "null"]
        },
        "type": {
          "type": "string"
        }
      },
      "required": [
        "name",
        "type",
        "is_primary_key",
        "is_foreign_key",
        "is_nullable"
      ]
    },
    "ErdStats": {
      "description": "ERD statistics",
      "type": "object",
      "properties": {
        "column_count": {
          "type": "integer",
          "minimum": 0
        },
        "relationship_count": {
          "type": "integer",
          "minimum": 0
        },
        "table_count": {
          "type": "integer",
          "minimum": 0
        }
      },
      "required": ["table_count", "column_count", "relationship_count"]
    },
    "RelationshipJson": {
      "description": "JSON representation of a relationship",
      "type": "object",
      "properties": {
        "cardinality": {
          "type": "string"
        },
        "from_column": {
          "type": "string"
        },
        "from_table": {
          "type": "string"
        },
        "to_column": {
          "type": "string"
        },
        "to_table": {
          "type": "string"
        }
      },
      "required": [
        "from_table",
        "from_column",
        "to_table",
        "to_column",
        "cardinality"
      ]
    },
    "TableJson": {
      "description": "JSON representation of a table with full column details",
      "type": "object",
      "properties": {
        "columns": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/ColumnJson"
          }
        },
        "name": {
          "type": "string"
        }
      },
      "required": ["name", "columns"]
    }
  }
}