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.
In discussing DB2 Connect, we will often refer to the term 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.
Another key concept is distributed unit of work, also known as multisite update. A distributed unit of work (DUOW) involves more than one database server within a unit of work. We define multisite update more specifically as a transaction having the following characteristics:
For more information on multisite update, see Enabling Multisite Updates (Two-Phase Commit).