Fujitsu UDS/SQL V2.5 用户手册
Database distribution
Database design
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U929-J-Z125-9-76
One DBH - multiple databases
This constellation is also referred to as multi-DB operation. Many application programs work
with two or more databases simultaneously. An application program (AP) may access
several databases within a single transaction. The DBH controls the processing of the
databases and ensures the consistency of all the data resources.
with two or more databases simultaneously. An application program (AP) may access
several databases within a single transaction. The DBH controls the processing of the
databases and ensures the consistency of all the data resources.
The databases that are operated by a DBH are part of a database configuration.
Figure 6: Multi-DB operation
Reasons for distributing data over multiple databases:
–
Data that is used only at certain times or for certain tasks can be stored in a separate
database, which need not be connected the whole time.
database, which need not be connected the whole time.
–
A large-scale database project is more easily implemented by gradually developing
additional databases.
additional databases.
AP1
AP2
AP3
DB1
DB2
DB3
DBH
DB1 DB2 DB3
DB1 DB3
DB1
AP1 AP2 AP3
AP1
AP1 AP3
Configuration