You can define regular LOB or XML variables,
LOB or XML locator variables, and LOB or XML file reference variables.
Regular LOB or XML variables, LOB or XML locator
variables, and LOB or XML file reference variables can be defined
in the following host languages:
PL/I (LOB only)
Where LOBs or XML are allowed, the term variable in
a syntax diagram can refer to a regular variable, a locator variable,
or a file reference variable. Since these variables are not native
data types in host programming languages, SQL extensions are used
and the precompilers generate the host language constructs necessary
to represent each variable.
When it is possible to define
a variable that is large enough to hold an entire LOB or XML value
and the performance benefit of delaying the transfer of data from
the server is not required, a LOB or XML locator is not needed. However,
it is often not acceptable to store an entire LOB or XML value in
temporary storage due to host language restrictions, storage restrictions,
or performance requirements. When storing a entire LOB or XML value
at one time is not acceptable, a LOB or XML value can be referred
to by a LOB or XML locator and portions of the LOB or XML value can
be accessed.