A list of database objects.
A list of slot names, or
t
.
A boolean.
The class of the objects, or
nil
.
A non-negative integer, or
nil
.
The function
update-objects-joins
updates the remote join slots, that is those slots defined without
:retrieval
:immediate
.
This is an optimization function which can improve the efficiency of an application by reducing the number of queries of the database. For each slot, it queries the database using the data from all the objects, and then assigns the appropriate value to each object.
objects
is a list of database objects. If
class-name
is non-
nil
, then all the database objects are of this class. If
class-name
is
nil
, then all the database objects are of the class of the first database object in the list
objects
.
If
objects
is
nil
, then
update-objects-joins
does nothing.
class-name
specifies a class containing all the database objects in the list
objects
. If
class-name
is
nil
(the default) then the class of the first database object is used.
slots provides a list of the names of slots to update. Each of these slots should be a remote join slot (as defined above).
slots
can also be
t
, meaning update all the remote join slots. The default value of
slots
is
t
.
force-p
controls whether to force the update of all values in the objects. If
force-p
is
nil
, then slots which are already are not updated. The default value of
force-p
is
t
.
max-len
, if non-
nil
, is a maximum number of objects from which to use data in a single query. If the length of the list
objects
is greater than
max-len
then
update-objects-joins
performs multiple queries using the data from no more than
max-len
objects in each query. This is useful if the DBMS may reject large queries, but it will increase the number of queries and hence reduce overall performance to some extent. The default value of
max-len
is the value of the variable *default-update-objects-max-len*.