refORM: Death to ORMs in .NET

Data Access is a difficult area to master. There are plenty of frameworks such as Entity Framework, NHibernate, i/myBatis. These frameworks attempt to make data access simpler but while these products are widely used they can lead to leaky abstractions forcing us to work around constraints of the technology or introduce the nightmare of trying to figure out what is happening deep down in the frameworks internals.

In this session we will look at the various lightweight alternatives and the advantages they offer as well as provide rationale about why the more heavyweight approach isn’t always the best approach.

Transcript

2. “A  Propos  de  Moi”   @kouphax   h*p://yobriefca.se   h*p://github.com/kouphax  
3. Disclaimer   This  presenta;on  is  full  of  opinion.    My  opinion.    The  fact  is   ORMs  have  been  around  for  a  long  ;me  and  will  be  for  a  while   yet.    If  things  were  as  simple  as  I  portray  them  in  this   presenta;on  you  wouldn’t  be  using  them  today.      But  you   probably  are.     All  I  ask  is  that  you  never  blindly  use  an  ORM  or  any  technology   without  prior  brain  thinking™  
4. On  with  the  show…  
5. ORMs  are  for  Life…   •  So  you’ve  adopted  an  ORM,  possibly   –  NHibernate   –  MyBa;s   –  En;ty  Framework   •  The  samples,  blogs  and  demos  promise  you  a   be*er  life,  your  “hello  world”  grade  apps  are   easy  and  it  adds  another  shiny  buzzword  to  your   CV  (Resume  Driven  Development)   •  You  dive  right  in  inves;ng  a  heap  of  development   cycles,  things  start  out  well…  
6. Suddenly  and  Without  Warning…  
7. The  Cracks  Start  To  Show   •  Leaky  Abstrac;ons   •  Bugger  to  debug   •  Forced  to  work  for  the  ORM  rather  than  the  ORM   working  for  you   •  DBAs  begin  to  call  you  names   •  Code  genera;on  and  heavy  use  of  model-­‐ pollu;ng  a*ributes  bog  you  down   •  Cost  of  change  is  high   •  Overreliance  on  ORMs  make  you  dumb  
9. ORMs  in  .NET  –  More  Like  WTFs   •  NHibernate   – HQL  –  WTF?   •  MyBa;s   – XML  as  a  medium  for  SQL?  –  WTF?   •  En;ty  Framework   – Great  demoware  but  the  reality  is  more  like  WTF?  
10. Lets  Be  Honest   •  How  many  features  of  a  heavyweight  ORM  do   you  really  use  regularly?    80%?  20%?  10%?   •  How  many  of  these  features  exist  purely  to   support  the  abstrac;on?   •  How  difficult  is  the  mapping  between  DB’s   and  objects  really?     •  Isn’t  SQL  the  best  DSL  for  working  with  data  in   a  rela;onal  database?      
11. So  why  is  this  abstracMon  necessary?  
12. It  isn’t.  
13. •  Historically  speaking  the  alterna;ves  were  pre*y   slim.    Most  people  would  need  to  roll  their  own   project  specific  data  access  layer   •  Many  ORMs  grew  out  of  that  sort  of  thinking  but   from  a  community  that  thought  XML  was  sexy   –  Some  people  are  weird   •  The  world  is  a  saner  place  these  days.       –  Reflec;on  is  faster   –  Sta;cally  typed  languages  have  embraced  dynamics,   and,   –  most  people  realise  XML  is  a  noisy  medium  for  almost   everything  
14. The  Advent  of  Micro  ORMs  
15. Level  of  AbstracMon   ADO.NET   Dapper   ORMLite   Massive   PetaPoco   Simple.Data   ADO.NET   Dapper   ORMLite   Massive   PetaPoco   Simple.Data   iBaMs   EnMty  Framework   NHibernate   Micro  ORMs   Heavyweight  ORMs  
16. Dapper  
17. Dapper   •  Created  by  Sam  Saffron  of  Stackoverflow   •  Single  file  (available  on  Nuget)   •  Set  of  extension  methods  to  IDbConnec;on   •  Supports  most  .NET  ADO  providers   –  SQL  Server,  Oracle,  SQLite,  MySQL,  SQL  CE     •  Works  on  boths  POCOs  and  dynamic  objects   •  Pre*y  close  to  the  metal   –  No  connec;on  handling   –  No  helpers  for  INSERT,  DELETE,  UPDATE  etc.   •  Community  extensions  for  CRUD  opera;ons   •  .NET  3.5  support  
18. Demo  
19. Queries   Dapper  
20. Inserts,  Updates  &  Deletes   Dapper  
21. Inserts,  Updates  &  Deletes  (CE)   Dapper  
22. •  Dapper  is  very  close  to  the  metal   •  Very  li*le  in  the  way  of  providing  helpers  for   1..N,  N..N  rela;onships   •  Dapper  Community  Extensions  bridge  some  of   the  mental  gap  for  people  not  used  to  SQL   And  the  rest…   Dapper  
23. ORMLite  
24. ORMLite   •  Part  of  the  ServiceStack  technology  suite   •  Set  of  CRUD  extensions  around  System.Data.*   namespace   •  Currently  supports  SQLite  and  SQL  Server   •  Maps  data  to  and  from  concrete  POCOs   –  Via  conven;on   –  Via  a*ributes  on  the  POCO  –  preferred   –  Via  raw  SQL   •  Relies  heavily  on  POCO  a*ribu;on   •  Supports  .NET  3.5  
25. Demo  
26. Configura;on   ORMLite  
27. Queries   ORMLite  
28. Inserts,  Updates  &  Deletes   ORMLite  
29. •  ORMLite  also  allows  you  to  create  tables  from   en;;es   •  Each  model  must  have  an  Id  property  which   must  be  its  primary  key.   •  Integrates  into  the  rest  of  the  ServiceStack   technology  stack   And  the  rest…   ORMLite  
30. Massive  
31. Massive   •  Created  by  Rob  Conrey   •  Single  file  (available  on  Nuget)   •  Makes  extensive  use  of  dynamics   •  No  mapping  to  POCOs  for  queries   •  Prefers  to  wrap  tables  rather  than  en;;es   –  Provides  a  single  point  of  configura;on   –  No  need  for  a*ributes   •  OOTB  Paging  support   •  .NET  4  Only  
32. Demo  
33. Crea;ng  the  Dynamic  Model   Massive  
34. Queries   Massive  
35. Inserts,  Updates  &  Deletes   Massive  
36. •  Valida;ons   •  Events   •  Also  Github  says…   – Asynchronous  support  for  queries   – Ability  to  reflect  Schema  Metadata   – Ability  to  generate  a  (DB)  default  row   – Factory  method  for  ad  hoc/on  the  fly  queries   And  the  rest…   Massive  
37. PetaPoco  
38. PetaPoco   •  Yet  another  single  file  (and  on  Nuget)   •  Inspired  by  Massive  and  Subsonic   •  Supports  POCOs  (and  op;onal  a*ributes)   •  Paging  and  transac;on  support  OOTB   •  Works  with  SQL  Server,  SQL  Server  CE,  MySQL,   PostgreSQL  and  Oracle.   •  .NET  3.5  upwards  
39. Demo  
40. Crea;ng  the  Database   PetaPoco  
41. Queries   PetaPoco  
42. Inserts,  Updates  &  Deletes   PetaPoco  
43. •  Out  of  the  box  support  for  1..N,  N..N  fetching   of  objects   – Slightly  awkward  approach   – Rela;onExtensions  project  abstracts  this   awkwardness  for  1..N,  N..1  queries   •  Provides  a  set  of  T4  Templates  for  genera;ng   POCOs  from  DB  schema     And  the  rest…   PetaPoco  
44. Simple.Data  
45. Simple.Data     •  Slightly  different  beast  though  it’s  principles  are  firmly  in   the  MicroORM  camp.   •  Data  Access  Component   –  Not  just  for  rela;onal  databases   –  NoSQL  support   –  Extensible  Adapter/Provider  support   •  Supports  a  wide  range  of  data  stores   –  SQL  Server,  SQL  Server  CE,  Oracle,  MySQL,  SQLite,  MongoDB   •  .NET  4  only   •  Extensive  use  of  dynamics  and  meta-­‐programming   concepts.   –  TryInvokeMember,  Method  name  reflec;on  
46. Demo  
47. Crea;ng  the  Database   Simple.Data  
48. Queries   Simple.Data  
49. Inserts,  Updates  &  Deletes   Simple.Data  
50. •  Inclusion  of  Simple.Data  here  may  seem  like  a   bit  of  contradic;on.    Arer  all  it  is  a  straight  up   abstrac;on.   •  It  makes  the  95th  cen;le  of  all  CRUD  tasks   “simple”   •  Ability  to  compose  DAL  from  other  lightweight   frameworks  for  the  other  edge  case  tasks   – Addi;ve  approach  rather  than  upfront  monolithic   approach   And  the  rest…   Simple.Data