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authorBoris Kolpackov <boris@codesynthesis.com>2015-02-04 17:23:54 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2015-02-04 17:23:54 +0200
commit0ac8f52ddfae8537651c65b8ab8b32db47756e74 (patch)
treebe6239b8e7f528c7c25a05f83af2ec806043fbd6 /view
parent613da395f986ff748448d5afc06319f84a734397 (diff)
Implement object loading views
See section 10.2 in the manual for details.
Diffstat (limited to 'view')
-rw-r--r--view/README5
-rw-r--r--view/driver.cxx38
-rw-r--r--view/employee.hxx15
-rw-r--r--view/makefile2
4 files changed, 57 insertions, 3 deletions
diff --git a/view/README b/view/README
index 0ade8ea..cba23b9 100644
--- a/view/README
+++ b/view/README
@@ -28,13 +28,14 @@ employee.sql
following command line:
odb -d <database> --generate-schema --generate-query \
- --default-pointer std::tr1::shared_ptr employee.hxx
+ --default-pointer std::tr1::shared_ptr --generate-session employee.hxx
Where <database> stands for the database system we are using, for example,
'mysql'.
The --default-pointer option is used to make TR1 shared_ptr the default
- object pointer.
+ object pointer. The --generate-session option is used to enable session
+ support for all the objects which is required to use object loading views.
database.hxx
Contains the create_database() function which instantiates the concrete
diff --git a/view/driver.cxx b/view/driver.cxx
index cbe26ee..74d6eed 100644
--- a/view/driver.cxx
+++ b/view/driver.cxx
@@ -277,6 +277,44 @@ main (int argc, char* argv[])
t.commit ();
}
+ // The same but using the object loading view.
+ //
+ {
+ typedef odb::query<employee_country_objects> query;
+ typedef odb::result<employee_country_objects> result;
+
+ transaction t (db->begin ());
+
+ // We have to use a session in order for the object pointers
+ // in our view and object pointers inside objects that we load
+ // to point to the same instances, where appropriate.
+ //
+ session s;
+
+ result r (db->query<employee_country_objects> (
+ query::res::name == query::nat::name));
+
+ cout << "Employees residing inside the country of nationality" << endl;
+
+ for (result::iterator i (r.begin ()); i != r.end (); ++i)
+ {
+ assert (i->e->nationality () == i->nat);
+ assert (i->e->residence () == i->res);
+
+ const employee& e (*i->e);
+ const country& r (*i->res);
+ const country& n (*i->nat);
+
+ cout << " " << e.first () << " " << e.last () << " "
+ << r.name () << " " << n.name () << endl;
+ }
+
+ cout << endl;
+
+ t.commit ();
+ }
+
+
// Get the list of employees that have accumulated vacation days.
//
{
diff --git a/view/employee.hxx b/view/employee.hxx
index 39d494f..87f0bce 100644
--- a/view/employee.hxx
+++ b/view/employee.hxx
@@ -239,6 +239,21 @@ struct employee_country
std::string nat_country_name;
};
+// An example of an object loading view. It is a different version of
+// the above view that loads the complete objects instead of a subset
+// of their data members.
+//
+#pragma db view object(employee) \
+ object(country = res: employee::residence_) \
+ object(country = nat: employee::nationality_)
+struct employee_country_objects
+{
+ shared_ptr<employee> e;
+ shared_ptr<country> res;
+ shared_ptr<country> nat;
+};
+
+
// An example of a native view that provides a complete query and is based
// on an ad-hoc table. This view allows us to load the employee vacation
// information from the legacy employee_extra table.
diff --git a/view/makefile b/view/makefile
index cfb061a..ca85d9b 100644
--- a/view/makefile
+++ b/view/makefile
@@ -46,7 +46,7 @@ gen := $(addprefix $(out_base)/,$(genf))
$(gen): $(odb)
$(gen): odb := $(odb)
$(gen) $(dist): export odb_options += --generate-query --generate-schema \
---default-pointer std::tr1::shared_ptr --table-prefix view_
+--default-pointer std::tr1::shared_ptr --generate-session --table-prefix view_
$(gen): cpp_options := -I$(src_base)
$(gen): $(odb.l.cpp-options)