What is the difference between the Data Mapper, Table Data Gateway (Gateway), Data Access Object (DAO) and Repository patterns?

by

Your example terms; DataMapper, DAO, DataTableGateway and Repository, all have a similar purpose (when I use one, I expect to get back a Customer object), but different intent/meaning and resulting implementation.

A Repository “acts like a collection, except with more elaborate querying capability” [Evans, Domain Driven Design] and may be considered as an “objects in memory facade” (Repository discussion)

A DataMapper “moves data between objects and a database while keeping them independent of each other and the mapper itself” (Fowler, PoEAA, Mapper)

A TableDataGateway is “a Gateway (object that encapsulates access to an external system or resource) to a database table. One instance handles all the rows in the table” (Fowler, PoEAA, TableDataGateway)

A DAO “separates a data resource’s client interface from its data access mechanisms / adapts a specific data resource’s access API to a generic client interface” allowing “data access mechanisms to change independently of the code that uses the data” (Sun Blueprints)

Repository seems very generic, exposing no notion of database interaction.
A DAO provides an interface enabling different underlying database implementations to be used.
A TableDataGateway is specifically a thin wrapper around a single table.
A DataMapper acts as an intermediary enabling the Model object to evolve independently of the database representation (over time).

More Related Contents:

  1. Writing large number of records (bulk insert) to Access in .NET/C#
  2. Should I abstract the validation framework from Domain layer?
  3. Why use AsQueryable() instead of List()?
  4. Repository Pattern Step by Step Explanation [closed]
  5. how to provide value to parent class constructor where parent constructor have more argument than child class from static void main in c#? [closed]
  6. Detect if deserialized object is missing a field with the JsonConvert class in Json.NET
  7. Using Linq to group a list of objects into a new grouped list of list of objects
  8. Reading Datetime value From Excel sheet
  9. How do foreach loops work in C#? [closed]
  10. Hide TabControl buttons to manage stacked Panel controls
  11. Regex to get NUMBER only from String
  12. auto create database in Entity Framework Core
  13. Implementing Hoey Shamos algorithm with C#
  14. Register Background Task in Silverlight 8.1 app
  15. Select Multiple Fields from List in Linq
  16. Get Master Sound Volume in c#
  17. Efficient way to round double precision numbers to a lower precision given in number of bits
  18. Why is there a difference in checking null against a value in VB.NET and C#?
  19. Accessing Excel Custom Document Properties programmatically
  20. How to detect mouse clicks?
  21. Can’t create huge arrays
  22. Why is this F# code so slow?
  23. ASP.net Getting the error “Access to the path is denied.” while trying to upload files to my Windows Server 2008 R2 Web server
  24. Setup Entity Framework For Dynamic Connection String
  25. Cannot find JavaScriptSerializer in .Net 4.0
  26. How to change the port number for Asp.Net core app?
  27. Convert DateTime to long and also the other way around
  28. Converting a byte array to PNG/JPG [closed]
  29. How to deserialize object derived from Exception class using Json.net?
  30. C# moving the mouse around realistically

Leave a Comment