Distributed Relational Database Architecture

Distributed Relational Database Architecture™ (DRDA) is a set of protocols that permits multiple database systems, which includes both IBM and not IBM systems, as well as application programs, to work together.

Any combination of relational database management products that use DRDA can be connected to form a distributed relational database management system. DRDA coordinates communication between systems by defining what must be exchanged and how it must be exchanged.

Unit of work
A unit of work (UOW) is a single logical transaction. It consists of a sequence of SQL statements in which either all of the operations are successfully performed or the sequence as a whole is considered unsuccessful.
Distributed unit of work
A distributed unit of work (DUOW), also known as multisite update, involves more than one database server within a unit of work. A DUOW has the following characteristics:
  • More than one database management server is updated per unit of work.
  • The application directs the distribution of work, and initiates commit.
  • There might be multiple requests per unit of work.
  • There is one database management server per request.
  • Commitment is coordinated across multiple database servers.