Use appropriate LIKE statement in per-model basis. Closes #1676

lib/rails_admin/adapters/active_record.rb

@@ -105,7 +105,7 @@ def initialize(scope)
 
         def add(field, value, operator)
           field.searchable_columns.flatten.each do |column_infos|
-            statement, value1, value2 = StatementBuilder.new(column_infos[:column], column_infos[:type], value, operator).to_statement
+            statement, value1, value2 = StatementBuilder.new(column_infos[:column], column_infos[:type], value, operator, @scope.connection.adapter_name).to_statement
             @statements << statement if statement.present?
             @values << value1 unless value1.nil?
             @values << value2 unless value2.nil?
@@ -153,10 +153,15 @@ def filter_scope(scope, filters, fields = config.list.fields.select(&:filterable
       end
 
       def build_statement(column, type, value, operator)
-        StatementBuilder.new(column, type, value, operator).to_statement
+        StatementBuilder.new(column, type, value, operator, model.connection.adapter_name).to_statement
       end
 
       class StatementBuilder < RailsAdmin::AbstractModel::StatementBuilder
+        def initialize(column, type, value, operator, adapter_name)
+          super column, type, value, operator
+          @adapter_name = adapter_name
+        end
+
       protected
 
         def unary_operators
@@ -269,7 +274,7 @@ def build_statement_for_uuid
         end
 
         def ar_adapter
-          ::ActiveRecord::Base.connection.adapter_name.downcase
+          @adapter_name.downcase
         end
       end
     end

spec/rails_admin/adapters/active_record_spec.rb

@@ -256,6 +256,16 @@ def build_statement(type, value, operator)
         end
       end
 
+      it 'chooses like statement in per-model basis' do
+        connection = double('connection')
+        allow(FieldTest).to receive(:connection).and_return(connection)
+
+        allow(connection).to receive(:adapter_name).and_return('postgresql')
+        expect(build_statement(:string, 'foo', 'default')).to eq(['(field ILIKE ?)', '%foo%'])
+        allow(connection).to receive(:adapter_name).and_return('sqlite3')
+        expect(build_statement(:string, 'foo', 'default')).to eq(['(LOWER(field) LIKE ?)', '%foo%'])
+      end
+
       it "supports '_blank' operator" do
         [['_blank', ''], ['', '_blank']].each do |value, operator|
           expect(build_statement(:string, value, operator)).to eq(["(field IS NULL OR field = '')"])