diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..6c7a8e0
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2018 amphp
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/src/Connector.php b/src/Connector.php
deleted file mode 100644
index 33354d7..0000000
--- a/src/Connector.php
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-namespace Amp\Sql;
-
-use Amp\Promise;
-
-interface Connector {
-    /**
-     * @param string $connectionString
-     *
-     * @return Promise<Connection>
-     */
-    public function connect(string $connectionString): Promise;
-}
diff --git a/src/ResultSet.php b/src/ResultSet.php
index 8f14ba7..e70295b 100644
--- a/src/ResultSet.php
+++ b/src/ResultSet.php
@@ -5,7 +5,7 @@ namespace Amp\Sql;
 use Amp\Iterator;
 use Amp\Promise;
 
-interface ResultSet extends Iterator {
+interface ResultSet extends Iterator, Operation {
     const FETCH_ARRAY = 0;
     const FETCH_ASSOC = 1;
     const FETCH_OBJECT = 2;
diff --git a/src/Transaction.php b/src/Transaction.php
index 5a800cb..b73da74 100644
--- a/src/Transaction.php
+++ b/src/Transaction.php
@@ -4,55 +4,22 @@ namespace Amp\Sql;
 
 use Amp\Promise;
 
-interface Transaction extends Operation {
+interface Transaction extends Executor, Operation {
     const UNCOMMITTED  = 0;
     const COMMITTED    = 1;
     const REPEATABLE   = 2;
     const SERIALIZABLE = 4;
 
-    /**
-     * {@inheritdoc}
-     *
-     * Closes and commits all changes in the transaction.
-     */
-    public function close();
-
     /**
      * @return int
      */
     public function getIsolationLevel(): int;
 
-    /**
-     * {@inheritdoc}
-     */
-    public function isAlive(): bool;
-
     /**
      * @return bool True if the transaction is active, false if it has been committed or rolled back.
      */
     public function isActive(): bool;
 
-    /**
-     * {@inheritdoc}
-     *
-     * @throws \Amp\Sql\TransactionError If the transaction has been committed or rolled back.
-     */
-    public function query(string $sql): Promise;
-
-    /**
-     * {@inheritdoc}
-     *
-     * @throws \Amp\Sql\TransactionError If the transaction has been committed or rolled back.
-     */
-    public function prepare(string $sql): Promise;
-
-    /**
-     * {@inheritdoc}
-     *
-     * @throws \Amp\Sql\TransactionError If the transaction has been committed or rolled back.
-     */
-    public function execute(string $sql, array $params = []): Promise;
-
     /**
      * Commits the transaction and makes it inactive.
      *