Distributed Relational Database Architecture

Distributed Relational Database Architecture™ (DRDA®) is a set of protocols that permits multiple database systems, both IBM and non-IBM, 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.