Add mysql.table_exists() convenience function

rattail_fabric2/mysql.py

@@ -93,6 +93,16 @@ def grant_access(c, dbname, username):
     sql(c, 'grant all on `{}`.* to {}'.format(dbname, username))
 
 
+def table_exists(c, tblname, dbname):
+    """
+    Determine if given table exists in given DB.
+    """
+    # TODO: should avoid sql injection here...
+    query = "SELECT TABLE_NAME FROM TABLES WHERE TABLE_SCHEMA = '{}' AND TABLE_NAME = '{}'".format(dbname, tblname)
+    name = sql(c, query, database='information_schema').stdout.strip()
+    return name == tblname
+
+
 def sql(c, sql, database=''):
     """
     Execute some SQL.