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.