Defer raising an exception when calling Connection.gettype() for a type

containing an attribute or element with an unsupported data type until
the first attempt to reference the attribute or element with the
unsupported data type.

Author: anthony-tuininga

doc/src/api_manual/module.rst

@@ -2277,6 +2277,12 @@ when binding data.
     :data:`DATETIME`.
 
 
+.. data:: DB_TYPE_UNSUPPORTED
+
+    Describes columns, attributes or array elements in a database that are
+    unknown and unsupported.
+
+
 .. data:: DB_TYPE_UROWID
 
     Describes columns, attributes or array elements in a database that are of

doc/src/release_notes.rst

@@ -35,6 +35,10 @@ Thick Mode Changes
     detected.
 #)  Added support for the "signed int", "signed long" and "decimal128" scalar
     types in JSON (generally only seen when converting from MongoDB).
+#)  Defer raising an exception when calling :meth:`Connection.gettype()`
+    for a type containing an attribute or element with an unsupported data type
+    until the first attempt to reference the attribute or element with the
+    unsupported data type.
 
 Common Changes
 ++++++++++++++

src/oracledb/base_impl.pxd

@@ -67,6 +67,7 @@ cdef enum:
     DB_TYPE_NUM_TIMESTAMP = 2012
     DB_TYPE_NUM_TIMESTAMP_LTZ = 2014
     DB_TYPE_NUM_TIMESTAMP_TZ = 2013
+    DB_TYPE_NUM_UNSUPPORTED = 0
     DB_TYPE_NUM_UROWID = 2030
     DB_TYPE_NUM_VARCHAR = 2001
 

src/oracledb/impl/base/types.pyx

@@ -56,7 +56,7 @@ cdef dict db_type_by_ora_type_num = {}
 
 cdef class DbType:
 
-    def __init__(self, num, name, ora_name, ora_type_num, default_size=0,
+    def __init__(self, num, name, ora_name, ora_type_num=0, default_size=0,
                  csfrm=0, buffer_size_factor=0):
         cdef uint16_t ora_type_key = csfrm * 256 + ora_type_num
         self.num = num
@@ -160,6 +160,8 @@ DB_TYPE_TIMESTAMP_LTZ = DbType(DB_TYPE_NUM_TIMESTAMP_LTZ,
 DB_TYPE_TIMESTAMP_TZ = DbType(DB_TYPE_NUM_TIMESTAMP_TZ, "DB_TYPE_TIMESTAMP_TZ",
                               "TIMESTAMP WITH TZ", 181,
                               buffer_size_factor=13)
+DB_TYPE_UNSUPPORTED = DbType(DB_TYPE_NUM_UNSUPPORTED, "DB_TYPE_UNSUPPORTED",
+                             "UNSUPPORTED")
 DB_TYPE_UROWID = DbType(DB_TYPE_NUM_UROWID, "DB_TYPE_UROWID", "UROWID", 208)
 DB_TYPE_VARCHAR = DbType(DB_TYPE_NUM_VARCHAR, "DB_TYPE_VARCHAR", "VARCHAR2",
                          1, 4000, csfrm=1, buffer_size_factor=4)