Do I need an ORM ?

Written on May 2, 2015
Estimated reading time : 2 mins
Tags : | database | orm |

Problem Statement

  • Many popular database products such as structured query language database management systems (SQL DBMS) can only store and manipulate scalar values such as integers and strings organized within tables.
  • The programmer must either :
    1. Convert the object values into groups of simpler values for storage in the database (and convert them back upon retrieval) (ORM !!!)
      • Only use simple scalar values within the program :
      • Via Procedural Code
      • Via OO Code with DAO Design Pattern - Use an Object Oriented Database (subset of NoSQL)


  • Object-relational mapping is a programming technique for converting data between incompatible type systems in object-oriented programming languages.
  • This creates, in effect, a “virtual object database” that can be used from within the programming language.

Advantages / Pros

  • Reduction in code

      /* Eg in Normal Code */
      String sql = "SELECT * FROM persons WHERE id = 10";
      DbCommand cmd = new DbCommand(connection, sql);
      Result res = cmd.Execute();
      String name = res[0]["FIRST_NAME"];
      /* Eg in ORM Code */
      Person p = Person.Get(10); 
      String name = p.getFirstName();
  • Easy development in most cases

Dis-advantages / Cons

  • Exponential Complexity
    • ORM tends to be useful for 70-80% of requirements which are generally simple but the rest requires you to hack around some limitations of the ORM or use raw queries instead (not cacheable !)
  • Performance
    • It is due to the fact that they use wildcard * for selecting data.
    • Compiling queries from ORM code is slow (eg : Doctrine ORM compiler is written in PHP)
    • Slower than traditional queries though it can be offset to a large extent by using opcode caching.
  • High level of abstraction obscuring what is actually happening in the implementation code.
  • Heavy reliance on ORM software has been cited as a major factor in producing poorly designed databases


  • A good ORM can definitely reduce development time & encourage use of OOP concepts.
  • Usually 70% of the requirements tend to be simple & can easily be implemented via ORM within a short time (relative to a non ORM solution).
  • For the rest, a good ORM provides for means to execute complex queries directly.
  • For a good performance, you will have to use an opcode cache layer + a data cache layer (memcache, varnish etc) so as to offset the speed issue. If you don’t want to do this, then ORM solution is not for you.


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