让查询变得更优雅
让查询变得更优雅RailsWhere可以让代码变得更简洁。
看一下插件的自述文件。
Ruby代码
=== Returning SQL
sql = Where.new('x=?',5).and( Where.new('x=?',6).or('x=?',7)).to_s
# returns (x=5) and ( (x=6) or (x=7) )
=== Building a complicated where clause made easy
def get_search_query_string
where = Where.new
where.and('users.first_name like ?', params[:search_first_name] + '%') unless params[:search_first_name].blank?
where.and('users.last_name like ?', params[:search_last_name] + '%') unless params[:search_last_name].blank?
status_where = Where.new
for status in params.split(',')
status_where.or 'status=?', status
end
where.and status_where unless status_where.blank?
where.to_s
end
User.find(:all, :conditions => get_search_query_string)
=== Inline
User.find(:all, :conditions => Where.new('first_name like ?', 'Tim').and('last_name like ?', 'Harper'))
Rails2.2.2下可以直接运行,Rails2.3.4的话,需要进行小小的改动:
Ruby代码
# RAILS_ROOT/vendor/railswhere/lib/where.rb
# 2.2.2
@criteria = ActiveRecord::Base.send(:sanitize_sql_array, criteria)
# 2.3.4
@criteria = ActiveRecord::Base.send(:sanitize_sql_array, criteria, nil) Rails发展更新得太快,3.0/3.1的变化还是比较大。 一点也不优雅,过度包装 功能的累加,必然导致复杂度和过度包装。
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