{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "api-layer/database-query/v1.0.0",
  "title": "Database Query APIs Schema",
  "description": "Schema for unified database query API (Integration Point 5.5)",
  "type": "object",
  "required": ["query_id", "database", "operation", "timestamp"],
  "properties": {
    "query_id": {
      "type": "string",
      "description": "Unique identifier for query",
      "pattern": "^query-[a-z0-9-]+$"
    },
    "database": {
      "type": "string",
      "enum": ["sqlite", "postgresql", "redis"],
      "description": "Target database"
    },
    "operation": {
      "type": "string",
      "enum": ["select", "insert", "update", "delete", "upsert", "transaction"],
      "description": "Database operation"
    },
    "timestamp": {
      "type": "string",
      "format": "date-time",
      "description": "Query timestamp"
    },
    "query": {
      "type": "object",
      "description": "Query details",
      "required": ["statement"],
      "properties": {
        "statement": {
          "type": "string",
          "description": "SQL statement or query"
        },
        "parameters": {
          "type": "array",
          "description": "Query parameters (parameterized queries)",
          "items": {}
        },
        "table": {
          "type": "string",
          "description": "Target table"
        }
      }
    },
    "result": {
      "type": "object",
      "description": "Query result",
      "properties": {
        "success": {
          "type": "boolean"
        },
        "rows_affected": {
          "type": "integer",
          "minimum": 0
        },
        "rows_returned": {
          "type": "integer",
          "minimum": 0
        },
        "data": {
          "type": "array",
          "description": "Result data (for SELECT)"
        },
        "error": {
          "type": "object",
          "description": "Error information if query failed",
          "properties": {
            "code": {
              "type": "string"
            },
            "message": {
              "type": "string"
            }
          }
        }
      }
    },
    "error_handling": {
      "type": "object",
      "description": "Standardized error handling",
      "required": ["error_code", "error_message"],
      "properties": {
        "error_code": {
          "type": "string",
          "description": "Standardized error code across databases"
        },
        "error_message": {
          "type": "string",
          "description": "Human-readable error message"
        },
        "original_error": {
          "type": "object",
          "description": "Original database-specific error"
        }
      }
    },
    "performance": {
      "type": "object",
      "description": "Query performance metrics",
      "properties": {
        "execution_time_ms": {
          "type": "integer",
          "minimum": 0
        },
        "optimized": {
          "type": "boolean",
          "description": "Whether query is optimized"
        },
        "index_used": {
          "type": "boolean",
          "description": "Whether database index was used"
        },
        "monitored": {
          "type": "boolean",
          "description": "Whether query performance is monitored"
        }
      }
    },
    "optimization": {
      "type": "object",
      "description": "Query optimization",
      "properties": {
        "explain_plan": {
          "type": "string",
          "description": "Query execution plan (EXPLAIN)"
        },
        "recommendations": {
          "type": "array",
          "items": {
            "type": "string"
          }
        }
      }
    },
    "api_interface": {
      "type": "object",
      "description": "Unified API interface",
      "properties": {
        "endpoint": {
          "type": "string",
          "pattern": "^/api/database/.*"
        },
        "method": {
          "type": "string",
          "enum": ["POST", "GET"]
        },
        "standardized": {
          "type": "boolean",
          "description": "Whether using standardized interface"
        }
      }
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "query_id": "query-select-agents-001",
      "database": "sqlite",
      "operation": "select",
      "timestamp": "2025-11-17T10:30:00Z",
      "query": {
        "statement": "SELECT * FROM agents WHERE status = ? AND confidence >= ?",
        "parameters": ["completed", 0.75],
        "table": "agents"
      },
      "result": {
        "success": true,
        "rows_affected": 0,
        "rows_returned": 5,
        "data": [
          {
            "id": "backend-001",
            "status": "completed",
            "confidence": 0.92
          }
        ]
      },
      "performance": {
        "execution_time_ms": 15,
        "optimized": true,
        "index_used": true,
        "monitored": true
      },
      "api_interface": {
        "endpoint": "/api/database/query",
        "method": "POST",
        "standardized": true
      }
    }
  ]
}