Add database::erase_query() function

New test: common/erase-query. Documentation is in Section 3.9, "Deleting
Persistent Objects". The current implementation does not work well with
the session (no removal of the erased objects from the cache).

3 files changed, 66 insertions, 0 deletions

diff --git a/odb/database.hxx b/odb/database.hxx
index c4458d9..2e6c79d 100644
--- a/odb/database.hxx
+++ b/odb/database.hxx
@@ -125,6 +125,24 @@ namespace odb
     void
     erase (const typename object_traits<T>::pointer_type& obj_ptr);
 
+    // Erase multiple objects matching a query predicate.
+    //
+    template <typename T>
+    unsigned long long
+    erase_query ();
+
+    template <typename T>
+    unsigned long long
+    erase_query (const char*);
+
+    template <typename T>
+    unsigned long long
+    erase_query (const std::string&);
+
+    template <typename T>
+    unsigned long long
+    erase_query (const odb::query<typename object_traits<T>::object_type>&);
+
     // Query API.
     //
     template <typename T>
diff --git a/odb/database.ixx b/odb/database.ixx
index a308bfe..ccbbe41 100644
--- a/odb/database.ixx
+++ b/odb/database.ixx
@@ -170,6 +170,39 @@ namespace odb
   }
 
   template <typename T>
+  inline unsigned long long database::
+  erase_query ()
+  {
+    // T can be const T while object_type will always be T.
+    //
+    typedef typename odb::object_traits<T>::object_type object_type;
+
+    return erase_query<T> (odb::query<object_type> ());
+  }
+
+  template <typename T>
+  inline unsigned long long database::
+  erase_query (const char* q)
+  {
+    // T can be const T while object_type will always be T.
+    //
+    typedef typename odb::object_traits<T>::object_type object_type;
+
+    return erase_query<T> (odb::query<object_type> (q));
+  }
+
+  template <typename T>
+  inline unsigned long long database::
+  erase_query (const std::string& q)
+  {
+    // T can be const T while object_type will always be T.
+    //
+    typedef typename odb::object_traits<T>::object_type object_type;
+
+    return erase_query<T> (odb::query<object_type> (q));
+  }
+
+  template <typename T>
   inline result<T> database::
   query (bool cache)
   {
diff --git a/odb/database.txx b/odb/database.txx
index 832c7ad..e60d7a8 100644
--- a/odb/database.txx
+++ b/odb/database.txx
@@ -208,6 +208,21 @@ namespace odb
   }
 
   template <typename T>
+  unsigned long long database::
+  erase_query (const odb::query<typename object_traits<T>::object_type>& q)
+  {
+    // T can be const T while object_type will always be T.
+    //
+    typedef typename odb::object_traits<T>::object_type object_type;
+    typedef odb::object_traits<object_type> object_traits;
+
+    if (!transaction::has_current ())
+      throw not_in_transaction ();
+
+    return object_traits::erase_query (*this, q);
+  }
+
+  template <typename T>
   result<T> database::
   query (const odb::query<typename object_traits<T>::object_type>& q,
          bool cache)