Selecto.Output.Formats (Selecto v0.4.5)

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Format registry and configuration system for Selecto output formats.

This module manages the registration and configuration of different output formats and provides the main interface for transforming query results from the default {rows, columns, aliases} format to other formats like maps, structs, JSON, CSV, etc.

Summary

Types

format_spec()

Functions

available_formats()

Get available format types and their descriptions.

performance_info(format)

Get performance characteristics for a given format.

transform(result, format, options \\ [])

Transform query results from the default format to the specified output format.

validate_format(format, options \\ [])

Validate format specification and options.

Types

format_spec()

@type format_spec() ::
  :raw
  | :maps
  | :json
  | :csv
  | {:maps, keyword()}
  | {:structs, module()}
  | {:json, keyword()}
  | {:csv, keyword()}
  | {:stream, format_spec()}
  | {:typed_maps, keyword()}

Functions

available_formats()

Get available format types and their descriptions.

Returns a list of available formats with their capabilities and options.

performance_info(format)

Get performance characteristics for a given format.

Returns information about memory usage, processing time, and scalability.

transform(result, format, options \\ [])

@spec transform({list(), list(), map()}, format_spec(), keyword()) ::
  {:ok, term()} | {:error, term()}

Transform query results from the default format to the specified output format.

Parameters

  • result - The query result tuple {rows, columns, aliases}
  • format - The output format specification
  • options - Additional options for the transformation

Format Specifications

  • :raw - Return the original {rows, columns, aliases} format (no transformation)
  • :maps - Transform to list of maps with string keys
  • {:maps, options} - Transform to maps with additional options
  • {:structs, struct_module} - Transform to list of structs
  • :json - Transform to JSON string
  • {:json, options} - Transform to JSON with options
  • :csv - Transform to CSV string
  • {:csv, options} - Transform to CSV with options
  • {:stream, format} - Transform to stream (for large datasets)

Examples

# Original format (no transformation)
{:ok, {rows, columns, aliases}} = transform(result, :raw)

# Maps with string keys
{:ok, maps} = transform(result, :maps)

# Maps with atom keys
{:ok, maps} = transform(result, {:maps, keys: :atoms})

# Custom struct
{:ok, structs} = transform(result, {:structs, Customer})

# JSON string
{:ok, json_string} = transform(result, :json)

# CSV with headers
{:ok, csv_string} = transform(result, {:csv, headers: true})

validate_format(format, options \\ [])

Validate format specification and options.

Returns :ok if the format is valid, {:error, reason} otherwise.