Added the ability to query for database pragmas and other db-specific

variables.

bin/weedb/__init__.py

@@ -121,6 +121,16 @@ class Connection(object):
         should raise an exception of type weedb.ProgrammingError if the table does not exist."""
         raise NotImplementedError
 
+    def get_variable(self, var_name):
+        """Return a database specific operational variable. Generally, things like 
+        pragmas, or optimization-related variables.
+        
+        It returns a 2-way tuple:
+        (variable-name, variable-value)
+        If the variable does not exist, it returns None.
+        """
+        raise NotImplemented
+    
     def begin(self):
         raise NotImplementedError
 

bin/weedb/mysql.py

@@ -169,6 +169,18 @@ class Connection(weedb.Connection):
         column_list = [row[1] for row in self.genSchemaOf(table)]
         return column_list
 
+    @guard
+    def get_variable(self, var_name):
+        cursor = self.connection.cursor()
+        try:
+            cursor.execute("SHOW VARIABLES LIKE '%s';" % var_name)
+            row = cursor.fetchone()
+            # This is actually a 2-way tuple (variable-name, variable-value),
+            # or None, if the variable does not exist.
+            return row
+        finally:
+            cursor.close()
+
     @guard
     def begin(self):
         """Begin a transaction."""
@@ -182,7 +194,6 @@ class Connection(weedb.Connection):
     def rollback(self):
         self.connection.rollback()
 
-
 class Cursor(object):
     """A wrapper around the MySQLdb cursor object"""
 

bin/weedb/sqlite.py

@@ -153,6 +153,16 @@ class Connection(weedb.Connection):
             raise weedb.ProgrammingError("No such table %s" % table)
         return column_list
 
+    @guard
+    def get_variable(self, var_name):
+        cursor = self.connection.cursor()
+        try:
+            cursor.execute("PRAGMA %s;" % var_name)
+            row = cursor.fetchone()
+            return None if row is None else (var_name, row[0])
+        finally:
+            cursor.close()
+
     @guard
     def begin(self):
         self.connection.execute("BEGIN TRANSACTION")

bin/weedb/test/test_weedb.py

@@ -197,17 +197,34 @@ class TestSqlite(Common):
         self.db_dict = sqlite_db_dict
         super(TestSqlite, self).__init__(*args, **kwargs)
         
+    def test_variable(self):
+        weedb.create(self.db_dict)
+        _connect = weedb.connect(self.db_dict)
+        _v = _connect.get_variable('journal_mode')
+        self.assertEqual(_v[1].lower(), 'delete')
+        _v = _connect.get_variable('foo')
+        self.assertEqual(_v, None)
+        _connect.close()
+        
 class TestMySQL(Common):
     
     def __init__(self, *args, **kwargs):
         self.db_dict = mysql_db_dict
         super(TestMySQL, self).__init__(*args, **kwargs)
-        
+
+    def test_variable(self):
+        weedb.create(self.db_dict)
+        _connect = weedb.connect(self.db_dict)
+        _v = _connect.get_variable('lower_case_table_names')
+        self.assertTrue(_v[1] in ['0', '1', '2'], "Unknown lower_case_table_names value")
+        _v = _connect.get_variable('foo')
+        self.assertEqual(_v, None)
+        _connect.close()
     
 def suite():
     tests = ['test_drop', 'test_double_create', 'test_no_db', 'test_no_tables', 
              'test_create', 'test_bad_table', 'test_select', 'test_bad_select',
-             'test_rollback', 'test_transaction']
+             'test_rollback', 'test_transaction', 'test_variable']
     return unittest.TestSuite(map(TestSqlite, tests) + map(TestMySQL, tests))
 
 if __name__ == '__main__':