Added table_oid, table_column on cursor.description items

Close psycopg#661

Author: dvarrazzo

psycopg/column.h

@@ -39,6 +39,10 @@ typedef struct {
   PyObject *scale;
   PyObject *null_ok;
 
+  /* Extensions to the DBAPI */
+  PyObject *table_oid;
+  PyObject *table_column;
+
 } columnObject;
 
 #endif /* PSYCOPG_COLUMN_H */

psycopg/column_type.c

@@ -62,7 +62,15 @@ static const char scale_doc[] =
     "None for other types.";
 
 static const char null_ok_doc[] =
-    "Always none.\n\n";
+    "Always none.";
+
+static const char table_oid_doc[] =
+    "The OID of the table from which the column was fetched.\n\n"
+    "None if not available";
+
+static const char table_column_doc[] =
+    "The number (within its table) of the column making up the result\n\n"
+    "None if not available. Note that PostgreSQL column numbers start at 1";
 
 
 static PyMemberDef column_members[] = {
@@ -73,6 +81,8 @@ static PyMemberDef column_members[] = {
     { "precision", T_OBJECT, offsetof(columnObject, precision), READONLY, (char *)precision_doc },
     { "scale", T_OBJECT, offsetof(columnObject, scale), READONLY, (char *)scale_doc },
     { "null_ok", T_OBJECT, offsetof(columnObject, null_ok), READONLY, (char *)null_ok_doc },
+    { "table_oid", T_OBJECT, offsetof(columnObject, table_oid), READONLY, (char *)table_oid_doc },
+    { "table_column", T_OBJECT, offsetof(columnObject, table_column), READONLY, (char *)table_column_doc },
     { NULL }
 };
 
@@ -89,12 +99,12 @@ column_init(columnObject *self, PyObject *args, PyObject *kwargs)
 {
     static char *kwlist[] = {
         "name", "type_code", "display_size", "internal_size",
-        "precision", "scale", "null_ok", NULL};
+        "precision", "scale", "null_ok", "table_oid", "table_column", NULL};
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|OOOOOOO", kwlist,
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|OOOOOOOOO", kwlist,
             &self->name, &self->type_code, &self->display_size,
             &self->internal_size, &self->precision, &self->scale,
-            &self->null_ok)) {
+            &self->null_ok, &self->table_oid, &self->table_column)) {
         return -1;
     }
 
@@ -112,6 +122,8 @@ column_dealloc(columnObject *self)
     Py_CLEAR(self->precision);
     Py_CLEAR(self->scale);
     Py_CLEAR(self->null_ok);
+    Py_CLEAR(self->table_oid);
+    Py_CLEAR(self->table_column);
 
     Py_TYPE(self)->tp_free((PyObject *)self);
 }
@@ -294,6 +306,16 @@ column_setstate(columnObject *self, PyObject *state)
         self->null_ok = PyTuple_GET_ITEM(state, 6);
         Py_INCREF(self->null_ok);
     }
+    if (size > 7) {
+        Py_CLEAR(self->table_oid);
+        self->table_oid = PyTuple_GET_ITEM(state, 7);
+        Py_INCREF(self->table_oid);
+    }
+    if (size > 8) {
+        Py_CLEAR(self->table_column);
+        self->table_column = PyTuple_GET_ITEM(state, 8);
+        Py_INCREF(self->table_column);
+    }
 
 exit:
     rv = Py_None;

psycopg/pqpath.c

@@ -1207,6 +1207,8 @@ _pq_fetch_tuples(cursorObject *curs)
         Oid ftype = PQftype(curs->pgres, i);
         int fsize = PQfsize(curs->pgres, i);
         int fmod =  PQfmod(curs->pgres, i);
+        Oid ftable = PQftable(curs->pgres, i);
+        int ftablecol = PQftablecol(curs->pgres, i);
 
         columnObject *column = NULL;
         PyObject *type = NULL;
@@ -1299,7 +1301,18 @@ _pq_fetch_tuples(cursorObject *curs)
             column->scale = tmp;
         }
 
-        /* 6/ FIXME: null_ok??? */
+        /* table_oid, table_column */
+        if (ftable != InvalidOid) {
+            PyObject *tmp;
+            if (!(tmp = PyInt_FromLong((long)ftable))) { goto err_for; }
+            column->table_oid = tmp;
+        }
+
+        if (ftablecol > 0) {
+            PyObject *tmp;
+            if (!(tmp = PyInt_FromLong((long)ftablecol))) { goto err_for; }
+            column->table_column = tmp;
+        }
 
         PyTuple_SET_ITEM(description, i, (PyObject *)column);
         column = NULL;

tests/test_cursor.py

@@ -377,7 +377,7 @@ def test_iter_named_cursor_rownumber(self):
         for i, rec in enumerate(curs):
             self.assertEqual(i + 1, curs.rownumber)
 
-    def test_namedtuple_description(self):
+    def test_description_attribs(self):
         curs = self.conn.cursor()
         curs.execute("""select
             3.14::decimal(10,2) as pi,
@@ -412,6 +412,27 @@ def test_namedtuple_description(self):
         self.assertEqual(c.precision, None)
         self.assertEqual(c.scale, None)
 
+    def test_description_extra_attribs(self):
+        curs = self.conn.cursor()
+        curs.execute("""
+            create table testcol (
+                pi decimal(10,2),
+                hi text)
+            """)
+        curs.execute("select oid from pg_class where relname = %s", ('testcol',))
+        oid = curs.fetchone()[0]
+
+        curs.execute("insert into testcol values (3.14, 'hello')")
+        curs.execute("select hi, pi, 42 from testcol")
+        self.assertEqual(curs.description[0].table_oid, oid)
+        self.assertEqual(curs.description[0].table_column, 2)
+
+        self.assertEqual(curs.description[1].table_oid, oid)
+        self.assertEqual(curs.description[1].table_column, 1)
+
+        self.assertEqual(curs.description[2].table_oid, None)
+        self.assertEqual(curs.description[2].table_column, None)
+
     def test_pickle_description(self):
         curs = self.conn.cursor()
         curs.execute('SELECT 1 AS foo')