Postgresql compatability (#17)

* Node ids should be big ints

Use sqlalchemy BigInteger datatype for 64-bit ints

* Only include the foreign keys PRAGMA if using sqlite

Use the connect_record to test the dialect being used

fornax/api.py

@@ -20,6 +20,9 @@
 # enforce foreign key constrains in SQLite
 @event.listens_for(Engine, "connect")
 def _set_sqlite_pragma(dbapi_connection, connection_record):
+    dialect_name = connection_record._ConnectionRecord__pool._dialect.name
+    if dialect_name != 'sqlite':
+        return
     cursor = dbapi_connection.cursor()
     cursor.execute("PRAGMA foreign_keys=ON")
     cursor.close()

fornax/model.py

@@ -3,7 +3,7 @@
 from sqlalchemy import ForeignKey, ForeignKeyConstraint
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import relationship
-
+from sqlalchemy.types import BigInteger
 Base = declarative_base()
 
 
@@ -51,8 +51,8 @@ class Match(Base):
         )
     )
 
-    start = Column(Integer)
-    end = Column(Integer)
+    start = Column(BigInteger)
+    end = Column(BigInteger)
     start_graph_id = Column(Integer)
     end_graph_id = Column(Integer)
     query_id = Column(Integer)
@@ -96,7 +96,7 @@ class Node(Base):
         PrimaryKeyConstraint('graph_id', 'node_id'),
     )
     node_id = Column(
-        Integer,
+        BigInteger,
         CheckConstraint("node_id>=0", name="q_min_id_check")
     )
     graph_id = Column(Integer, ForeignKey("graph.graph_id"))
@@ -127,8 +127,8 @@ class Edge(Base):
         )
     )
 
-    start = Column(Integer)
-    end = Column(Integer)
+    start = Column(BigInteger)
+    end = Column(BigInteger)
     graph_id = Column(Integer)
     meta = Column(String, nullable=True)