Module advanced_types 

Advanced type operators and SQL templates for Week 5.

This module documents the implementation of advanced type operators that require specialized SQL generation or external libraries.

Geospatial Types (PostGIS)

Geospatial operators require PostGIS extensions on PostgreSQL, or equivalent spatial functions on other databases.

Coordinates Type

Represents a single point with latitude and longitude.

Format: JSON {lat: float, lng: float}

Operators:

• distanceWithin: Distance from point within radius (km)
• withinBoundingBox: Point within rectangular bounding box
• withinPolygon: Point within polygon (future enhancement)

Database Support:

• PostgreSQL: Native PostGIS support (ST_DWithin, ST_GeomFromText)
• MySQL: Built-in spatial functions (ST_Distance_Sphere)
• SQLite: Haversine formula approximation (no spatial library)
• SQL Server: Native geography type (ST_Distance)

Example Query:

query {
  restaurants(
    where: {
      location: {
        distanceWithin: {
          latitude: 40.7128
          longitude: -74.0060
          radiusKm: 5
        }
      }
    }
  ) {
    name
  }
}

Phone Number Type

Phone number operators provide E.164 format validation and country code extraction.

Format: E.164 string (e.g., “+14155552671”)

Operators:

• countryCodeEq: Country code matches
• countryCodeIn: Country code in list
• isValid: Valid E.164 format (+[1-9]{1,3}[0-9]{1,14})
• typeEq: Type classification (US, UK, OTHER)

Database Support:

• PostgreSQL: Regex matching with ‘^\+[1-9]’ pattern
• MySQL: REGEXP operator with escaping
• SQLite: GLOB patterns for basic matching
• SQL Server: LIKE patterns for matching

Notes:

• Full phone validation (including carrier type) requires phonenumber-rs
• Current implementation provides basic E.164 validation
• Country code extraction assumes standard E.164 format

Example Query:

query {
  users(
    where: {
      phone: {
        countryCodeEq: "+1"
      }
    }
  ) {
    phone
  }
}

Date Range Type

Date range operators provide range analysis and overlap detection.

Format: JSON with ISO 8601 dates

{
  "start": "2024-01-01T00:00:00Z",
  "end": "2024-12-31T23:59:59Z"
}

Operators:

• durationGte: Total duration >= min days
• startsAfter: Range starts after date
• endsBefore: Range ends before date
• overlaps: Overlaps with another date range

Database Support:

• PostgreSQL: Native timestamp and INTERVAL types
• MySQL: DATEDIFF and date functions
• SQLite: julianday for date arithmetic
• SQL Server: DATEDIFF and datetime functions

Example Query:

query {
  projects(
    where: {
      timeline: {
        durationGte: 90
        overlaps: {
          start: "2024-06-01T00:00:00Z"
          end: "2024-08-31T23:59:59Z"
        }
      }
    }
  ) {
    name
    timeline {
      start
      end
    }
  }
}

Duration Type

Duration operators convert ISO 8601 durations to seconds/minutes for range queries.

Format: ISO 8601 duration string

• “P1Y2M3DT4H5M6S” (1 year, 2 months, 3 days, 4 hours, 5 minutes, 6 seconds)
• “PT1H” (1 hour)
• “PT30M” (30 minutes)
• “PT45S” (45 seconds)

Operators:

• totalSecondsEq: Duration equals (in seconds)
• totalMinutesGte: Duration >= min (in minutes)

Database Support:

• PostgreSQL: CAST to INTERVAL, then EXTRACT(EPOCH …)
• MySQL: Parse PT notation and cast to numeric
• SQLite: Parse PT notation and cast to numeric
• SQL Server: SUBSTRING to parse and cast

Example Query:

query {
  tasks(
    where: {
      estimatedTime: {
        totalMinutesGte: 480
      }
    }
  ) {
    name
    estimatedTime
  }
}

Implementation Status

Type	Operator	PostgreSQL	MySQL	SQLite	SQL Server	Status
Coordinates	distanceWithin	✅ PostGIS	✅	⚠️ Approx	✅	Implemented
Coordinates	withinBoundingBox	✅	✅	✅	✅	Implemented
Phone	countryCodeEq	✅	✅	✅	✅	Implemented
Phone	isValid	✅ Regex	✅	⚠️ Basic	⚠️ Basic	Implemented
DateRange	durationGte	✅	✅	✅	✅	Implemented
DateRange	overlaps	✅	✅	✅	✅	Implemented
Duration	totalSecondsEq	✅	✅	✅	✅	Implemented
Duration	totalMinutesGte	✅	✅	✅	✅	Implemented

Performance Considerations

Geospatial Queries

• PostGIS indexes (GIST/BRIN) required for performance
• ST_DWithin uses index-aware distance calculation
• Bounding box queries are generally fast (simple range checks)

Date Range Queries

• Indexes on start/end timestamp fields recommended
• OVERLAP operations efficient with proper indexes
• Use separate indexed columns for start/end instead of JSON

Duration Parsing

• ISO 8601 parsing done in SQL (no application overhead)
• Regex validation in application layer (before SQL)

Limitations and Future Work

Current Limitations

• Phone validation limited to E.164 format (not carrier type)
• SQLite geospatial using Haversine approximation (not exact)
• No polygon containment without spatial extension
• ISO 8601 duration parsing requires standard format

Future Enhancements

• Full phone number validation via phonenumber-rs library
• PostGIS polygon operators (CoordinatesWithinPolygon)
• Advanced date range operations (gaps, unions)
• Time zone aware date operations
• Route distance calculation (requires routing library)

Structs

AdvancedTypesDocumentation

Marker type for documentation. This module documents advanced type operators but doesn’t export any functions (implementation is in sql_templates.rs).