(SQL) Media types: Refactor backrefnames.

We need to know the name of the backref, so that we can
access it by name on the MediaEntry. We might be able to
get this name by inspection, but this way is easier, for
now.

mediagoblin/media_types/ascii/models.py

@@ -22,6 +22,9 @@ from sqlalchemy import (
 from sqlalchemy.orm import relationship, backref
 
 
+BACKREF_NAME = "ascii__media_data"
+
+
 class AsciiData(Base):
     __tablename__ = "ascii__mediadata"
 
@@ -29,7 +32,7 @@ class AsciiData(Base):
     media_entry = Column(Integer, ForeignKey('core__media_entries.id'),
         primary_key=True)
     get_media_entry = relationship("MediaEntry",
-        backref=backref("ascii__media_data", cascade="all, delete-orphan"))
+        backref=backref(BACKREF_NAME, cascade="all, delete-orphan"))
 
 
 DATA_MODEL = AsciiData

mediagoblin/media_types/audio/models.py

@@ -22,6 +22,9 @@ from sqlalchemy import (
 from sqlalchemy.orm import relationship, backref
 
 
+BACKREF_NAME = "audio__media_data"
+
+
 class AudioData(Base):
     __tablename__ = "audio__mediadata"
 
@@ -29,7 +32,7 @@ class AudioData(Base):
     media_entry = Column(Integer, ForeignKey('core__media_entries.id'),
         primary_key=True)
     get_media_entry = relationship("MediaEntry",
-        backref=backref("audio__media_data", cascade="all, delete-orphan"))
+        backref=backref(BACKREF_NAME, cascade="all, delete-orphan"))
 
 
 DATA_MODEL = AudioData

mediagoblin/media_types/image/models.py

@@ -23,6 +23,9 @@ from sqlalchemy.orm import relationship, backref
 from mediagoblin.db.sql.extratypes import JSONEncoded
 
 
+BACKREF_NAME = "image__media_data"
+
+
 class ImageData(Base):
     __tablename__ = "image__mediadata"
 
@@ -30,7 +33,7 @@ class ImageData(Base):
     media_entry = Column(Integer, ForeignKey('core__media_entries.id'),
         primary_key=True)
     get_media_entry = relationship("MediaEntry",
-        backref=backref("image__media_data", cascade="all, delete-orphan"))
+        backref=backref(BACKREF_NAME, cascade="all, delete-orphan"))
 
     width = Column(Integer)
     height = Column(Integer)

mediagoblin/media_types/stl/models.py

@@ -22,6 +22,9 @@ from sqlalchemy import (
 from sqlalchemy.orm import relationship, backref
 
 
+BACKREF_NAME = "stl__media_data"
+
+
 class StlData(Base):
     __tablename__ = "stl__mediadata"
 
@@ -29,7 +32,7 @@ class StlData(Base):
     media_entry = Column(Integer, ForeignKey('core__media_entries.id'),
         primary_key=True)
     get_media_entry = relationship("MediaEntry",
-        backref=backref("stl__media_data", cascade="all, delete-orphan"))
+        backref=backref(BACKREF_NAME, cascade="all, delete-orphan"))
 
     center_x = Column(Float)
     center_y = Column(Float)

mediagoblin/media_types/video/models.py

@@ -22,6 +22,9 @@ from sqlalchemy import (
 from sqlalchemy.orm import relationship, backref
 
 
+BACKREF_NAME = "video__media_data"
+
+
 class VideoData(Base):
     __tablename__ = "video__mediadata"
 
@@ -29,7 +32,7 @@ class VideoData(Base):
     media_entry = Column(Integer, ForeignKey('core__media_entries.id'),
         primary_key=True)
     get_media_entry = relationship("MediaEntry",
-        backref=backref("video__media_data", cascade="all, delete-orphan"))
+        backref=backref(BACKREF_NAME, cascade="all, delete-orphan"))
 
     width = Column(SmallInteger)
     height = Column(SmallInteger)