diff --git a/datajoint/connection.py b/datajoint/connection.py
index ab00e3ab7..6ece857e3 100644
--- a/datajoint/connection.py
+++ b/datajoint/connection.py
@@ -4,7 +4,7 @@
 """
 
 from contextlib import contextmanager
-import pymysql as connector
+import pymysql as client
 import logging
 from . import config
 from . import DataJointError
@@ -59,7 +59,7 @@ def __init__(self, host, user, passwd, init_fun=None):
         else:
             port = config['database.port']
         self.conn_info = dict(host=host, port=port, user=user, passwd=passwd)
-        self._conn = connector.connect(init_command=init_fun, **self.conn_info)
+        self._conn = client.connect(init_command=init_fun, **self.conn_info)
         if self.is_connected:
             logger.info("Connected {user}@{host}:{port}".format(**self.conn_info))
         else:
@@ -96,15 +96,15 @@ def query(self, query, args=(), as_dict=False):
         Execute the specified query and return the tuple generator (cursor).
 
         :param query: mysql query
-        :param args: additional arguments for the connector.cursor
+        :param args: additional arguments for the client.cursor
         :param as_dict: If as_dict is set to True, the returned cursor objects returns
                         query results as dictionary.
         """
-        cursor = connector.cursors.DictCursor if as_dict else connector.cursors.Cursor
+        cursor = client.cursors.DictCursor if as_dict else client.cursors.Cursor
         cur = self._conn.cursor(cursor=cursor)
 
         # Log the query
-        logger.debug("Executing SQL:" + query)
+        logger.debug("Executing SQL:" + query[0:300])
         cur.execute(query, args)
         return cur
 
diff --git a/datajoint/relation.py b/datajoint/relation.py
index 1129de7f0..25f354607 100644
--- a/datajoint/relation.py
+++ b/datajoint/relation.py
@@ -2,6 +2,7 @@
 import numpy as np
 import logging
 import abc
+import binascii
 
 from . import config
 from . import DataJointError
@@ -181,24 +182,41 @@ def insert1(self, tup, replace=False, ignore_errors=False, skip_duplicates=False
         >>> relation.insert1(dict(subject_id=7, species="mouse", date_of_birth="2014-09-01"))
 
         """
+
         heading = self.heading
 
-        if isinstance(tup, np.void):    # np.array insert
-            for field in tup.dtype.fields:
-                if field not in heading:
-                    raise KeyError(u'{0:s} is not in the attribute list'.format(field))
-            values = ['%s' if heading[name].is_blob else tup[name] for name in heading if name in tup.dtype.fields]
-            attributes = [name for name in heading if name in tup.dtype.fields]
-            args = tuple(pack(tup[name]) for name in heading
-                         if name in tup.dtype.fields and heading[name].is_blob)
-        elif isinstance(tup, Mapping):   #  dict-based insert
-            for field in tup.keys():
+        def check_fields(fields):
+            for field in fields:
                 if field not in heading:
                     raise KeyError(u'{0:s} is not in the attribute list'.format(field))
-            values = ['%s' if heading[name].is_blob else tup[name] for name in heading if name in tup]
-            attributes = [name for name in heading if name in tup]
-            args = tuple(pack(tup[name]) for name in heading
-                         if name in tup and heading[name].is_blob)
+
+        def make_attribute(name, value):
+            """
+            For a given attribute, return its value or value placeholder as a string to be included
+            in the query and the value, if any to be submitted for processing by mysql API.
+            """
+            if heading[name].is_blob:
+                value = pack(value)
+                # This is a temporary hack to address issue #131 (slow blob inserts).
+                # When this problem is fixed by pymysql or python, then pass blob as query argument.
+                placeholder = '0x' + binascii.b2a_hex(value).decode('ascii')
+                value = None
+            elif heading[name].numeric:
+                if np.isnan(value):
+                    name = None    # omit nans
+                placeholder = '%s'
+                value = repr(int(value) if isinstance(value, bool) else value)
+            else:
+                placeholder = '%s'
+            return name, placeholder, value
+
+        if isinstance(tup, np.void):    # np.array insert
+            check_fields(tup.dtype.fields)
+            attributes = [make_attribute(name, tup[name])
+                          for name in heading if name in tup.dtype.fields]
+        elif isinstance(tup, Mapping):   # dict-based insert
+            check_fields(tup.keys())
+            attributes = [make_attribute(name, tup[name]) for name in heading if name in tup]
         else:    # positional insert
             try:
                 if len(tup) != len(heading):
@@ -209,14 +227,11 @@ def insert1(self, tup, replace=False, ignore_errors=False, skip_duplicates=False
             except TypeError:
                 raise DataJointError('Datatype %s cannot be inserted' % type(tup))
             else:
-                values = ['%s' if heading[name].is_blob else value for name, value in zip(heading, tup)]
-                attributes = heading.names
-                args = tuple(pack(value) for name, value in zip(heading, tup) if heading[name].is_blob)
-
-        value_list = ','.join(map(lambda elem: repr(elem) if elem != '%s' else elem , values))
-        attribute_list = '`' + '`,`'.join(attributes) + '`'
-
-        skip = skip_duplicates and (self & {a: v for a, v in zip(attributes, values) if heading[a].in_key})
+                attributes = [make_attribute(name, value) for name, value in zip(heading, tup)]
+        if not attributes:
+            raise DataJointError('Empty tuple')
+        skip = skip_duplicates and (
+            self & {name: value for name, _, value in attributes if heading[name].in_key})
         if not skip:
             if replace:
                 sql = 'REPLACE'
@@ -224,10 +239,11 @@ def insert1(self, tup, replace=False, ignore_errors=False, skip_duplicates=False
                 sql = 'INSERT IGNORE'
             else:
                 sql = 'INSERT'
-            sql += " INTO %s (%s) VALUES (%s)" % (self.from_clause, attribute_list, value_list)
-            logger.info(sql)
-            self.connection.query(sql, args=args)
-
+            attributes = (a for a in attributes if a[0])   # omit dropped attributes
+            names, placeholders, values = tuple(zip(*attributes))
+            sql += " INTO %s (`%s`) VALUES (%s)" % (
+                self.from_clause, '`,`'.join(names), ','.join(placeholders))
+            self.connection.query(sql, args=tuple(v for v in values if v is not None))
 
     def delete_quick(self):
         """
diff --git a/tests/schema.py b/tests/schema.py
index f5f680338..587c69e1c 100644
--- a/tests/schema.py
+++ b/tests/schema.py
@@ -20,9 +20,7 @@ class Auto(dj.Lookup):
     contents = (
         dict(name="Godel"),
         dict(name="Escher"),
-        dict(name="Bach")
-    )
-
+        dict(name="Bach"))
 
 @schema
 class User(dj.Lookup):
diff --git a/tests/test_nan.py b/tests/test_nan.py
new file mode 100644
index 000000000..8eb0a3d55
--- /dev/null
+++ b/tests/test_nan.py
@@ -0,0 +1,27 @@
+import numpy as np
+from nose.tools import assert_true, assert_false, assert_equal, assert_list_equal
+import datajoint as dj
+from . import PREFIX, CONN_INFO
+
+
+schema = dj.schema(PREFIX + '_nantest', locals(), connection=dj.conn(**CONN_INFO))
+
+
+@schema
+class NanTest(dj.Manual):
+    definition = """
+    id :int
+    ---
+    value=null :double
+    """
+
+
+def test_insert_nan():
+    rel = NanTest()
+    a = np.array([1, 2, np.nan, np.pi, np.nan])
+    rel.insert(((i, value) for i, value in enumerate(a)))
+    b = rel.fetch.order_by('id')['value']
+    assert_true((np.isnan(a) == np.isnan(b)).all(),
+                'incorrect handling of Nans')
+    assert_true(np.allclose(a[np.logical_not(np.isnan(a))], b[np.logical_not(np.isnan(b))]),
+                'incorrect storage of floats')