{
  "$schema": "https://json-schema.org/draft/2020-12",
  "$id": "https://www.iso.org/schemas/sql-result",
  "title": "SQL Query Result",
  "description": "JSON Schema representing the result of a SQL query execution",
  "type": "object",
  "properties": {
    "columns": {
      "type": "array",
      "description": "Column metadata for SELECT results",
      "items": {
        "$ref": "#/$defs/ColumnMetadata"
      }
    },
    "rows": {
      "type": "array",
      "description": "Result rows as arrays of values matching the columns order",
      "items": {
        "type": "array",
        "items": {
          "oneOf": [
            { "type": "string" },
            { "type": "number" },
            { "type": "boolean" },
            { "type": "null" }
          ]
        }
      },
      "example": [
        [1, "Alice", "alice@example.com"],
        [2, "Bob", "bob@example.com"]
      ]
    },
    "rowsAsObjects": {
      "type": "array",
      "description": "Result rows as key/value objects using column names as keys",
      "items": {
        "type": "object",
        "additionalProperties": true
      },
      "example": [
        { "id": 1, "name": "Alice", "email": "alice@example.com" },
        { "id": 2, "name": "Bob", "email": "bob@example.com" }
      ]
    },
    "rowCount": {
      "type": "integer",
      "description": "Number of rows returned (SELECT) or affected (INSERT/UPDATE/DELETE)",
      "minimum": 0,
      "example": 2
    },
    "affectedRows": {
      "type": "integer",
      "description": "Number of rows modified by INSERT, UPDATE, or DELETE",
      "minimum": 0,
      "example": 1
    },
    "lastInsertId": {
      "type": ["string", "integer", "null"],
      "description": "Auto-generated ID of the last inserted row, if applicable",
      "example": 42
    },
    "executionTime": {
      "type": "number",
      "description": "Query execution time in milliseconds",
      "example": 12.5
    },
    "error": {
      "$ref": "#/$defs/SQLError"
    }
  },
  "$defs": {
    "ColumnMetadata": {
      "type": "object",
      "description": "Metadata for a single result column",
      "properties": {
        "name": {
          "type": "string",
          "description": "Column name as returned by the database",
          "example": "user_id"
        },
        "type": {
          "type": "string",
          "description": "SQL data type of the column",
          "example": "INTEGER"
        },
        "nullable": {
          "type": "boolean",
          "description": "Whether the column allows NULL values",
          "example": false
        },
        "primaryKey": {
          "type": "boolean",
          "description": "Whether this column is part of the primary key",
          "example": true
        }
      },
      "required": ["name"]
    },
    "SQLError": {
      "type": "object",
      "description": "SQL error information when a query fails",
      "properties": {
        "code": {
          "type": "string",
          "description": "SQL error code (e.g., SQLSTATE)",
          "example": "42P01"
        },
        "message": {
          "type": "string",
          "description": "Human-readable error message",
          "example": "relation \"users\" does not exist"
        },
        "position": {
          "type": "integer",
          "description": "Character position in the SQL string where the error occurred"
        }
      },
      "required": ["message"]
    }
  }
}