feat: Add --skip option for pagination through large tables

Add --skip option to skip a specified number of rows before exporting.
Useful for paginating through large datasets in combination with --max.

Also fixed default direction to 'ASC' when using --orderby without
explicit --direction.

Based on PR #143 by @whoisryosuke.

Author: tihomiro

README.md

@@ -215,6 +215,21 @@ php artisan iseed users --skip-fk-checks
 
 **Note**: This option generates MySQL-specific `SET FOREIGN_KEY_CHECKS` statements.
 
+### skip
+Optional parameter which defines the number of rows to skip before exporting. This is useful for paginating through large tables in combination with the `--max` option.
+
+Example:
+```
+php artisan iseed users --skip=1000
+```
+
+When combined with `--max` for pagination:
+```
+php artisan iseed users --max=1000 --orderby=id
+php artisan iseed users --max=1000 --skip=1000 --orderby=id
+php artisan iseed users --max=1000 --skip=2000 --orderby=id
+```
+
 ### where
 Optional parameter which allows you to specify a SQL WHERE clause to filter the rows that will be included in the seed file. The WHERE clause should be provided as a string and will be applied directly to the SQL query.
 

src/Orangehill/Iseed/Iseed.php

@@ -66,10 +66,11 @@ public function readStubFile($file)
      * @param  string   $postrunEvent
      * @param  bool     $register
      * @param  bool     $skipFkChecks
+     * @param  int      $skip
      * @return bool
      * @throws Orangehill\Iseed\TableNotFoundException
      */
-    public function generateSeed($table, $prefix = null, $suffix = null, $database = null, $max = 0, $chunkSize = 0, $exclude = null, $prerunEvent = null, $postrunEvent = null, $dumpAuto = true, $indexed = true, $orderBy = null, $direction = 'ASC', $whereClause = null, $register = true, $skipFkChecks = false)
+    public function generateSeed($table, $prefix = null, $suffix = null, $database = null, $max = 0, $chunkSize = 0, $exclude = null, $prerunEvent = null, $postrunEvent = null, $dumpAuto = true, $indexed = true, $orderBy = null, $direction = 'ASC', $whereClause = null, $register = true, $skipFkChecks = false, $skip = null)
     {
         if (!$database) {
             $database = config('database.default');
@@ -83,7 +84,7 @@ public function generateSeed($table, $prefix = null, $suffix = null, $database =
         }
 
         // Get the data
-        $data = $this->getData($table, $max, $exclude, $orderBy, $direction, $whereClause);
+        $data = $this->getData($table, $max, $exclude, $orderBy, $direction, $whereClause, $skip);
 
         // Repack the data
         $dataArray = $this->repackSeedData($data);
@@ -144,7 +145,7 @@ public function getSeedPath()
      * @param  string $table
      * @return Array
      */
-    public function getData($table, $max, $exclude = null, $orderBy = null, $direction = 'ASC', $whereClause = null)
+    public function getData($table, $max, $exclude = null, $orderBy = null, $direction = 'ASC', $whereClause = null, $skip = null)
     {
         $result = \DB::connection($this->databaseName)->table($table);
 
@@ -161,6 +162,10 @@ public function getData($table, $max, $exclude = null, $orderBy = null, $directi
             $result = $result->orderBy($orderBy, $direction);
         }
 
+        if ($skip) {
+            $result = $result->skip($skip);
+        }
+
         if ($max) {
             $result = $result->limit($max);
         }

src/Orangehill/Iseed/IseedCommand.php

@@ -72,8 +72,9 @@ public function fire()
          $indexed = !$this->option('noindex');
          $register = !$this->option('noregister');
          $skipFkChecks = $this->option('skip-fk-checks');
+         $skip = intval($this->option('skip'));
          $orderBy = $this->option('orderby');
-         $direction = $this->option('direction');
+         $direction = $this->option('direction') ?: 'ASC';
          $prefix = $this->option('classnameprefix');
          $suffix = $this->option('classnamesuffix');
          $whereClause = $this->option('where');
@@ -84,6 +85,9 @@ public function fire()
          if ($chunkSize < 1) {
              $chunkSize = null;
          }
+         if ($skip < 1) {
+             $skip = null;
+         }
 
          $tableIncrement = 0;
          foreach ($tables as $table) {
@@ -114,7 +118,8 @@ public function fire()
                          $direction,
                          $whereClause,
                         $register,
-                        $skipFkChecks
+                        $skipFkChecks,
+                        $skip
                      ),
                      $table
                  );
@@ -140,7 +145,8 @@ public function fire()
                          $direction,
                          $whereClause,
                         $register,
-                        $skipFkChecks
+                        $skipFkChecks,
+                        $skip
                      ),
                      $table
                  );
@@ -186,6 +192,7 @@ protected function getOptions()
             array('classnamesuffix', null, InputOption::VALUE_OPTIONAL, 'suffix for class and file name', null),
             array('where', null, InputOption::VALUE_OPTIONAL, 'where clause to filter records', null),
             array('skip-fk-checks', null, InputOption::VALUE_NONE, 'disable foreign key checks during seeding', null),
+            array('skip', null, InputOption::VALUE_OPTIONAL, 'number of rows to skip', null),
         );
     }