improve migration class

Schema.php

@@ -1,6 +1,7 @@
 <?php
 namespace DatabaseHelper;
 
+use DatabaseHelper\enums\Aggregation;
 use DatabaseHelper\enums\Charset;
 use DatabaseHelper\enums\Collation;
 use DatabaseHelper\enums\Engine;
@@ -38,6 +39,12 @@ class Schema
         return false;
     }
 
+    public function countEntries(): int {
+        return Database::makeQuery($this)
+            ->aggregate('*', 'count', Aggregation::COUNT)
+            ->query();
+    }
+
     public function columnType(string $col) {
         return $this->columns[$col]['type'];
     }
@@ -46,10 +53,6 @@ class Schema
         return $this->columns['primary']['name'];
     }
 
-    /**
-     * Creates a deep copy of this instance.
-     * @return Schema
-     */
     public function copy(): Schema {
         $copy = new Schema($this->name);
         $copy->columns = genericDeepCopy($this->columns);