Class: Jaql::SqlGeneration::Query

Inherits:
Object
  • Object
show all
Includes:
QueryParsing
Defined in:
lib/jaql/sql_generation/query.rb

Direct Known Subclasses

RunnableQuery

Constant Summary collapse

ARRAY_RETURN_TYPE = 
:array
ROW_RETURN_TYPE = 
:row

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(run_context, spec, resolver, table_name_alias = nil) ⇒ Query 



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# File 'lib/jaql/sql_generation/query.rb', line 10

def initialize(run_context, spec, resolver, table_name_alias=nil)
  @run_context = run_context or fail "#{self.class} must be initialized with a run_context"
  @resolver = resolver or fail "#{self.class} must be initialized with a resolver"
  @table_name_alias = table_name_alias

  # TODO deep stringify keys when spec is a hash
  hash_spec = spec.is_a?(String) ? JSON.parse(spec) : spec || {}
  validate!(hash_spec)
  @spec = hash_spec
end

Instance Attribute Details

#table_name_alias ⇒ Object (readonly)

public



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# File 'lib/jaql/sql_generation/query.rb', line 6

def table_name_alias
  @table_name_alias
end

Instance Method Details

#fields_sql ⇒ Object 



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# File 'lib/jaql/sql_generation/query.rb', line 50

def fields_sql
  return "#{query_table_name}.*" if fields.empty?

  fields.map {|field| field.to_sql}.join(",\n")
end

#json_array_sql(cte, display_name) ⇒ Object 



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# File 'lib/jaql/sql_generation/query.rb', line 42

def json_array_sql(cte, display_name)
  json_sql(cte, display_name, ARRAY_RETURN_TYPE)
end

#json_row_sql(cte, display_name) ⇒ Object 



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# File 'lib/jaql/sql_generation/query.rb', line 46

def json_row_sql(cte, display_name)
  json_sql(cte, display_name, ROW_RETURN_TYPE)
end

#json_sql(cte, display_name, return_type) ⇒ Object 



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# File 'lib/jaql/sql_generation/query.rb', line 24

def json_sql(cte, display_name, return_type)
  display_name or raise "display_name cannot be blank"

  rel = run_context.tmp_relation_name
  select_sql = case return_type
               when ARRAY_RETURN_TYPE
                 "coalesce(json_agg(#{rel}), '[]'::JSON)"
               when ROW_RETURN_TYPE
                 "row_to_json(#{rel})"
                 # uncomment this to return {} instead of nil for empty rows
                 # "coalesce(row_to_json(#{rel}), '{}'::JSON)"
               else
                 fail "unknown return type: '#{return_type}'"
               end

  %Q{( SELECT #{select_sql} AS "#{display_name}" FROM (#{cte}) #{rel} )}
end

#scope_options ⇒ Object 



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# File 'lib/jaql/sql_generation/query.rb', line 56

def scope_options
  spec.slice(*ASSOCIATION_SCOPE_OPTION_KEYS)
end