Merge pull request #8 from xmnlab/master

README updated; Initial changes to use execute method.

ibis/mapd/README.rst

@@ -69,6 +69,7 @@ database.
 The main classes are:
 
 - `MapDClient`
+- `MapDQuery`
 - `MapDDataType`
 
 `MapDDataType` class is used to translate data type from `ibis` and to `ibis`.
@@ -105,6 +106,34 @@ expression. Its main methods are:
 - get_schema
 - version
 
+`MapDQuery` class should be used redefine at least `_fetch` method. If `Query`
+class is used instead, when `MapDClient.execute` method is called, a exception
+is raised.
+
+compiler
+--------
+
+@TODO
+
+operations
+----------
+
+    `Node` subclasses make up the core set of operations of ibis.
+    Each node corresponds to a particular operation.
+    Most nodes are defined in the `operations` module.
+    (http://docs.ibis-project.org/design.html#the-node-class).
+
+
+identifiers
+-----------
+
+`identifiers` module keep a set of identifiers (`_identifiers`) to be used
+inside `quote_identifier` function (inside the same module). `_identifiers` is
+a set of reserved words from `MapD` language.
+
+`quote_identifiers` is used to put quotes around the string sent if the string
+match to specific criteria.
+
 References
 ----------
 

ibis/mapd/client.py

@@ -1,9 +1,11 @@
 from ibis.compat import parse_version
-from ibis.client import Database, SQLClient
+from ibis.client import Database, Query, SQLClient
 from ibis.mapd import compiler as comp
 from ibis.util import log
+from pymapd.cursor import Cursor
 
 import regex as re
+import pandas as pd
 import pymapd
 
 import ibis.common as com
@@ -74,11 +76,33 @@ def from_ibis(cls, dtype, nullable=None):
         return cls(typename, nullable=nullable)
 
 
+class MapDQuery(Query):
+    """
+
+    """
+    def execute(self):
+        cursor = self.client._execute(
+            self.compiled_ddl
+        )
+        result = self._fetch(cursor)
+        return self._wrap_result(result)
+
+    def _fetch(self, cursor):
+        # check if cursor is a pymapd cursor.Cursor
+        if isinstance(cursor, Cursor):
+            col_names = [c.name for c in cursor.description]
+            result = pd.DataFrame(cursor.fetchall(), columns=col_names)
+        else:
+            result = cursor
+        return self.schema().apply_to(result)
+
+
 class MapDClient(SQLClient):
     """
 
     """
     database_class = Database
+    sync_query = MapDQuery
     dialect = comp.MapDDialect
 
     def __init__(
@@ -145,16 +169,25 @@ def _get_table_schema(self, table_name):
             database, table_name = table_name_
         return self.get_schema(table_name, database)
 
-    def _execute(self, query):
-        with self.con as conn:
-            if self.execution_type == 1:
-                stmt_exec = conn.select_ipc_gpu
-            elif self.execution_type == 2:
-                self.stmt_exec = conn.select_ipc
-            else:
-                self.stmt_exec = conn.execute
+    def _execute(self, query, results=True):
+        """
 
-            return stmt_exec(query)
+        :param query:
+        :return:
+        """
+        if self.execution_type == 1:
+            stmt_exec = self.con.select_ipc_gpu
+        elif self.execution_type == 2:
+            stmt_exec = self.con.select_ipc
+        else:
+            stmt_exec = self.con.cursor().execute
+
+        result = stmt_exec(query)
+
+        if results:
+            return result
+        else:
+            return
 
     def database(self, name=None):
         """Connect to a database called `name`.

ibis/mapd/identifiers.py

@@ -108,7 +108,7 @@
 })
 
 
-def quote_identifier(name, quotechar='`', force=False):
+def quote_identifier(name, quotechar='"', force=False):
     if force or name.count(' ') or name in _identifiers:
         return '{0}{1}{0}'.format(quotechar, name)
     else:

ibis/mapd/operations.py

@@ -494,9 +494,6 @@ def _string_like(translator, expr):
     )
 
 
-# TODO: mapd uses different string functions
-#       for ascii and utf-8 encodings,
-
 _binary_infix_ops = {
     # Binary operations
     ops.Add: binary_infix_op('+'),