Query Object Pattern

A Query Object is an interpreter, that is, a structure of objects that can form itself into a SQL query (martin fowler).

  • When there is a need to avoid to know what the database schema looks like to form queries.

  • Hides the SQL inside parameterized methods.
  • Those who write the queries can do so independently of the database schema and changes to the schema can be localized in a single place.

  • Makes it difficult to form more ad hoc queries.

Sample Code


  1. Design pattern is an important concept to learn as they simplify the design and architecture of applications and systems. Problems based on design patterns and algorithms are frequently asked in programming interviews. Thank you for sharing your valuable knowledge. Great blog. Coding interview questions

  2. This is what exactly the specification pattern does as well.


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