Use arel instead custom SQL

camilova · Aug 9, 2022 · a10eb9e · a10eb9e
1 parent cfb0e29
commit a10eb9e
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Showing 2 changed files with 23 additions and 48 deletions.
diff --git a/lib/update_by_case.rb b/lib/update_by_case.rb
@@ -3,6 +3,7 @@
 require_relative "update_by_case/version"
 require_relative "update_by_case/utils"
 require "active_record"
+require "byebug" if ENV['ENV']&.downcase == 'development'
 
 module UpdateByCase
   extend ::ActiveSupport::Concern
@@ -12,37 +13,26 @@ module UpdateByCase
     class << self
 
       def update_by_case!(cases)
-        case_sql_fragment = ""
+        update_hash = {}
         cases.each do |attribute_name, attribute_cases|
           next if attribute_name&.to_s == Utils::WHERE_OPTION
-          if attribute_cases.is_a?(Hash) && attribute_cases.size == 1 && 
-            attribute_cases.first.second.is_a?(Hash) then
-            case_sql_fragment += Utils.separate_operator unless case_sql_fragment.empty?
-            case_sql_fragment += Utils.build_case_sql_fragment(
-              self,
-              attribute_name, 
-              attribute_cases.first.first, 
-              attribute_cases.first.second,
-            )
+          if attribute_cases.is_a?(Hash) && attribute_cases.size == 1 &&
+            attribute_cases.first&.second&.is_a?(Hash) then
+            cases = attribute_cases.first.second
+            key_attribute = attribute_cases.first.first
+            case_statement = Utils.build_case_statement(self, attribute_name, key_attribute, cases)
           elsif attribute_cases.is_a?(Hash) && attribute_cases.size.positive?
-            case_sql_fragment += Utils.separate_operator unless case_sql_fragment.empty?
-            case_sql_fragment += Utils.build_case_sql_fragment(
-              self,
-              attribute_name, 
-              primary_key, 
-              attribute_cases
-            )
+            key_attribute = primary_key
+            case_statement = Utils.build_case_statement(self, attribute_name, key_attribute, attribute_cases)
           elsif ! attribute_cases.is_a?(Hash)
             # Assume attribute_cases is only one value for all cases
-            case_sql_fragment += Utils.separate_operator unless case_sql_fragment.empty?
-            value = Utils.sql_value(attribute_cases)
-            sql_type = Utils.sql_type(self, attribute_name)
-            case_sql_fragment += "#{attribute_name}=#{value}::#{sql_type}#{Utils::SEPARATOR}"
+            case_statement = attribute_cases
+          else
+            raise 'invalid provided cases hash'
           end
+          update_hash[attribute_name] = case_statement
         end
-        instance = self
-        instance = where(cases[:where]) if cases[:where].present?
-        instance.update_all(case_sql_fragment)
+        where(cases[:where] || {}).update_all(update_hash)
       end
 
       def update_by_case(cases)

diff --git a/lib/update_by_case/utils.rb b/lib/update_by_case/utils.rb
@@ -1,34 +1,19 @@
+require 'arel'
+
 module UpdateByCase
   class Utils
     WHERE_OPTION = 'where'.freeze
-    SEPARATOR = (ENV['ENV']&.downcase == 'development' ? "\n" : " ").freeze
 
     class << self
 
-      def separate_operator
-        ",#{SEPARATOR}"
-      end
-
-      def sql_value(attribute_value)
-        attribute_value.nil?? 'NULL' : "'#{attribute_value}'"
-      end
-
-      def sql_type(model, attribute_name)
-        model.columns.find { |c| c.name.to_s == attribute_name.to_s }.sql_type
-      end
-
-      def build_case_sql_fragment(model, attribute_name, key_attribute, attribute_cases)
-        case_sql_fragment = "#{attribute_name}=(CASE #{key_attribute}#{SEPARATOR}"
-        attribute_cases.each do |key_attribute_value, attribute_value|
-          value = sql_value(attribute_value)
-          sql_key_attribute_value = key_attribute_value
-          if key_attribute_value.is_a?(String) || key_attribute_value.is_a?(Symbol)
-            sql_key_attribute_value = "'#{key_attribute_value}'"
-          end
-          case_sql_fragment += "WHEN #{sql_key_attribute_value} THEN #{value}#{SEPARATOR}"
+      def build_case_statement(model, attribute_name, key_attribute, cases)
+        case_statement = Arel::Nodes::Case.new
+        arel_table = model.arel_table
+        cases.each do |xcase|
+          condition = arel_table[key_attribute].eq(xcase.first)
+          case_statement.when(condition).then(xcase.second)
         end
-        sql_type = sql_type(model, attribute_name)
-        case_sql_fragment += "ELSE #{attribute_name} END)::#{sql_type}"
+        case_statement.else(arel_table[attribute_name])
       end
 
     end