First commit

vendor/PicoDb/Schema.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace PicoDb;
+
+class Schema
+{
+    protected $db = null;
+
+
+    public function __construct(Database $db)
+    {
+        $this->db = $db;
+    }
+
+
+    public function check($last_version = 1)
+    {
+        $current_version = $this->db->getConnection()->getSchemaVersion();
+
+        if ($current_version < $last_version) {
+
+            return $this->migrateTo($current_version, $last_version);
+        }
+
+        return true;
+    }
+
+
+    public function migrateTo($current_version, $next_version)
+    {
+        try {
+
+            $this->db->startTransaction();
+
+            for ($i = $current_version + 1; $i <= $next_version; $i++) {
+
+                $function_name = '\Schema\version_'.$i;
+
+                if (function_exists($function_name)) {
+
+                    call_user_func($function_name, $this->db->getConnection());
+                    $this->db->getConnection()->setSchemaVersion($i);
+                }
+                else {
+
+                    throw new \LogicException('To execute a database migration, you need to create this function: "'.$function_name.'".');
+                }
+            }
+
+            $this->db->closeTransaction();
+        }
+        catch (\PDOException $e) {
+
+            $this->db->cancelTransaction();
+            return false;
+        }
+
+        return true;
+    }
+}