Add View support (without DDL)

Given the Views behave similar to Tables on CRUD operations, they
are treated as if they were tables.

This patch insures that all operations available through a Table
object are also available if the underlying object is a View.

Table.is_view() method was added to verify if the underlying object
is a View.

Tests were added/changed for regression.

Author: nmariz

lib/mysqlx/crud.py

@@ -31,12 +31,15 @@
                         DropCollectionIndexStatement)
 
 
+_COUNT_VIEWS_QUERY = ("SELECT COUNT(*) FROM information_schema.views "
+                      "WHERE table_schema = '{0}' AND table_name = '{1}'")
 _COUNT_TABLES_QUERY = ("SELECT COUNT(*) FROM information_schema.tables "
                        "WHERE table_schema = '{0}' AND table_name = '{1}'")
 _COUNT_SCHEMAS_QUERY = ("SELECT COUNT(*) FROM information_schema.schemata "
                         "WHERE schema_name like '{0}'")
 _COUNT_QUERY = "SELECT COUNT(*) FROM `{0}`.`{1}`"
 _DROP_TABLE_QUERY = "DROP TABLE IF EXISTS `{0}`.`{1}`"
+_DROP_VIEW_QUERY = "DROP VIEW IF EXISTS `{0}`.`{1}`"
 
 
 class DatabaseObject(object):
@@ -96,6 +99,7 @@ def am_i_real(self):
     def who_am_i(self):
         return self.get_name()
 
+
 class Schema(DatabaseObject):
     """A client-side representation of a database schema. Provides access to
     the schema contents.
@@ -159,11 +163,11 @@ def get_tables(self):
         rows = self._connection.get_row_result("list_objects", self._name)
         rows.fetch_all()
         tables = []
+        object_types = ("TABLE", "VIEW",)
         for row in rows:
-            if row.get_string("type") != "TABLE":
-                continue
-            table = Table(self, row.get_string("name"))
-            tables.append(table)
+            if row.get_string("type") in object_types:
+                table = Table(self, row.get_string("name"))
+                tables.append(table)
         return tables
 
     def get_table(self, name, check_existence=False):
@@ -205,8 +209,13 @@ def drop_table(self, name):
         Args:
             name (str): The name of the table to be dropped.
         """
-        self._connection.execute_nonquery(
-            "sql", _DROP_TABLE_QUERY.format(self._name, name), False)
+        table = Table(self, name)
+        if table.is_view():
+            self._connection.execute_nonquery(
+                "sql", _DROP_VIEW_QUERY.format(self._name, name), False)
+        else:
+            self._connection.execute_nonquery(
+                "sql", _DROP_TABLE_QUERY.format(self._name, name), False)
 
     def create_collection(self, name, reuse=False):
         """Creates in the current schema a new collection with the specified
@@ -407,3 +416,12 @@ def count(self):
         """
         sql = _COUNT_QUERY.format(self._schema.name, self._name)
         return self._connection.execute_sql_scalar(sql)
+
+    def is_view(self):
+        """Determine if the underlying object is a view or not.
+
+        Returns:
+            bool: `True` if the underlying object is a view.
+        """
+        sql = _COUNT_VIEWS_QUERY.format(self._schema.get_name(), self._name)
+        return self._connection.execute_sql_scalar(sql) == 1

tests/test_mysqlx_crud.py

@@ -35,6 +35,8 @@
 
 _CREATE_TEST_TABLE_QUERY = "CREATE TABLE `{0}`.`{1}` (id INT)"
 _INSERT_TEST_TABLE_QUERY = "INSERT INTO `{0}`.`{1}` VALUES ({2})"
+_CREATE_TEST_VIEW_QUERY = ("CREATE VIEW `{0}`.`{1}` AS SELECT * "
+                           "FROM `{2}`.`{3}`;")
 _COUNT_TABLES_QUERY = ("SELECT COUNT(*) FROM information_schema.tables "
                        "WHERE table_schema = '{0}' AND table_name = '{1}'")
 
@@ -103,18 +105,21 @@ def test_get_tables(self):
         tables = self.schema.get_tables()
         self.assertEqual(0, len(tables), "Should have returned 0 objects")
 
-        self.node_session.sql("CREATE TABLE {0}.table1(id INT)"
-                              "".format(self.schema_name)).execute()
-        self.node_session.sql("CREATE TABLE {0}.table2(id INT)"
-                              "".format(self.schema_name)).execute()
-        self.node_session.sql("CREATE TABLE {0}.table3(id INT)"
-                              "".format(self.schema_name)).execute()
-
+        self.node_session.sql(_CREATE_TEST_TABLE_QUERY.format(
+            self.schema_name, "table1")).execute()
+        self.node_session.sql(_CREATE_TEST_TABLE_QUERY.format(
+            self.schema_name, "table2")).execute()
+        self.node_session.sql(_CREATE_TEST_TABLE_QUERY.format(
+            self.schema_name, "table3")).execute()
+        self.node_session.sql(_CREATE_TEST_VIEW_QUERY.format(
+            self.schema_name, "view1",
+            self.schema_name, "table1")).execute()
         tables = self.schema.get_tables()
-        self.assertEqual(3, len(tables), "Should have returned 3 objects")
+        self.assertEqual(4, len(tables), "Should have returned 4 objects")
         self.assertEqual("table1", tables[0].get_name())
         self.assertEqual("table2", tables[1].get_name())
         self.assertEqual("table3", tables[2].get_name())
+        self.assertEqual("view1", tables[3].get_name())
 
     def test_drop_collection(self):
         collection_name = "collection_test"
@@ -621,3 +626,19 @@ def test_column_metadata(self):
         self.assertEqual("active", col.get_column_name())
         self.assertEqual("test", col.get_table_name())
         self.assertEqual(mysqlx.ColumnType.BIT, col.get_type())
+
+    def test_is_view(self):
+        table_name = "table_test"
+        view_name = "view_test"
+        self.node_session.sql(_CREATE_TEST_TABLE_QUERY.format(
+            self.schema_name, table_name)).execute()
+        self.node_session.sql(_INSERT_TEST_TABLE_QUERY.format(
+            self.schema_name, table_name, "1")).execute()
+        table = self.schema.get_table(table_name)
+        self.assertFalse(table.is_view())
+
+        self.node_session.sql(_CREATE_TEST_VIEW_QUERY.format(
+            self.schema_name, view_name,
+            self.schema_name, table_name)).execute()
+        view = self.schema.get_table(view_name)
+        self.assertTrue(view.is_view())