Module: SqlChatbot::Grammar::Primitives

Defined in:
lib/sql_chatbot/grammar/primitives.rb

Constant Summary collapse

PREFERRED_DISPLAY_FIELDS = 
%w[id name title label email].freeze

Class Method Summary collapse

Class Method Details

.build(primitive:, entity:, field: nil, which: nil, n: nil, rank_field: nil, direction: nil, group_by: nil) ⇒ Object 



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# File 'lib/sql_chatbot/grammar/primitives.rb', line 22

def self.build(primitive:, entity:, field: nil, which: nil, n: nil, rank_field: nil, direction: nil, group_by: nil)
  t = q(entity.table)
  case primitive
  when :COUNT
    "SELECT COUNT(*) FROM #{t}"
  when :LIST
    "SELECT #{pick_display_fields(entity).map { |c| q(c) }.join(", ")} FROM #{t}"
  when :SUM
    require_field!(entity, field, "SUM")
    "SELECT SUM(#{qc(entity.table, field)}) FROM #{t}"
  when :AVG
    require_field!(entity, field, "AVG")
    "SELECT ROUND(AVG(#{qc(entity.table, field)}), 2) FROM #{t}"
  when :MIN_MAX
    require_field!(entity, field, "MIN_MAX")
    raise "MIN_MAX requires which" unless %i[MIN MAX].include?(which)
    "SELECT #{which}(#{qc(entity.table, field)}) FROM #{t}"
  when :TOP_N
    rank = rank_field || entity.ranking_candidates.first
    raise "TOP_N requires rankField" unless rank
    limit = n || 10
    dir = (direction || "desc").to_s.upcase
    # V1.3-V: NULLS LAST in both directions. PG default for DESC is
    # NULLS FIRST, which surfaced a NULL-rank row for 2BN's
    # "biggest review by rating" — answer LLM rendered "N/A".
    # NULL rank is never the answer the user wants.
    "SELECT #{pick_display_fields(entity).map { |c| q(c) }.join(", ")}, #{qc(entity.table, rank)} FROM #{t} ORDER BY #{qc(entity.table, rank)} #{dir} NULLS LAST LIMIT #{limit}"
  when :RANK
    raise "RANK requires rankField and groupBy" unless rank_field && group_by
    "SELECT #{t}.*, DENSE_RANK() OVER (PARTITION BY #{qc(entity.table, group_by)} ORDER BY #{qc(entity.table, rank_field)} DESC) AS rank FROM #{t}"
  else
    raise "unknown primitive #{primitive}"
  end
end

.pick_display_fields(entity) ⇒ Object 



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# File 'lib/sql_chatbot/grammar/primitives.rb', line 57

def self.pick_display_fields(entity)
  present = PREFERRED_DISPLAY_FIELDS.select { |p| entity.fields.key?(p) }
  return present.map { |p| entity.fields[p].column } if present.any?
  entity.fields.keys.first(4)
end

.q(name) ⇒ Object

Quote a single SQL identifier — wraps in double quotes and escapes embedded quotes. Prevents PG reserved-word collisions (“user”, “order” etc.) which silently resolve to functions and corrupt counts.



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# File 'lib/sql_chatbot/grammar/primitives.rb', line 13

def self.q(name)
  %("#{name.to_s.gsub('"', '""')}")
end

.qc(table, col) ⇒ Object

Qualified column reference: “table”.“column”



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# File 'lib/sql_chatbot/grammar/primitives.rb', line 18

def self.qc(table, col)
  "#{q(table)}.#{q(col)}"
end

.require_field!(entity, field, name) ⇒ Object 



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# File 'lib/sql_chatbot/grammar/primitives.rb', line 63

def self.require_field!(entity, field, name)
  raise "#{name} requires field" unless field
  raise "#{name} field '#{field}' not in entity" unless entity.fields.key?(field.to_s)
end