add exists functionality (similar to count but just checks existence)

DataStorage/Database/Mapper/DataMapperFactory.php

@@ -254,6 +254,20 @@ class DataMapperFactory
         return (new ReadMapper(new static(), $db ?? self::$db))->count();
     }
 
+    /**
+     * Create read mapper
+     *
+     * @param ConnectionAbstract $db Database connection
+     *
+     * @return ReadMapper
+     *
+     * @since 1.0.0
+     */
+    public static function exists(ConnectionAbstract $db = null) : ReadMapper
+    {
+        return (new ReadMapper(new static(), $db ?? self::$db))->exists();
+    }
+
     /**
      * Create read mapper
      *

DataStorage/Database/Mapper/MapperType.php

@@ -38,6 +38,8 @@ abstract class MapperType extends Enum
 
     public const COUNT_MODELS = 12;
 
+    public const MODEL_EXISTS = 13;
+
     // -------------------------------------------- //
 
     public const CREATE = 1001;

DataStorage/Database/Mapper/ReadMapper.php

@@ -102,6 +102,20 @@ final class ReadMapper extends DataMapperAbstract
         return $this;
     }
 
+    /**
+     * Create count mapper
+     *
+     * @return self
+     *
+     * @since 1.0.0
+     */
+    public function exists() : self
+    {
+        $this->type = MapperType::MODEL_EXISTS;
+
+        return $this;
+    }
+
     /**
      * Create random mapper
      *
@@ -158,6 +172,8 @@ final class ReadMapper extends DataMapperAbstract
                 return $this->executeGetRaw();
             case MapperType::COUNT_MODELS:
                 return $this->executeCount();
+            case MapperType::MODEL_EXISTS:
+                return $this->executeExists();
             default:
                 return null;
         }
@@ -227,7 +243,7 @@ final class ReadMapper extends DataMapperAbstract
         try {
             $results = false;
 
-            $sth = $this->db->con->prepare($a = $query->toSql());
+            $sth = $this->db->con->prepare($query->toSql());
             if ($sth !== false) {
                 $sth->execute();
                 $results = $sth->fetchAll(\PDO::FETCH_ASSOC);
@@ -285,6 +301,20 @@ final class ReadMapper extends DataMapperAbstract
         return (int) $query->execute()?->fetchColumn();
     }
 
+    /**
+     * Check if any element exists
+     *
+     * @return int
+     *
+     * @since 1.0.0
+     */
+    public function executeExists() : bool
+    {
+        $query = $this->getQuery(null, ['1']);
+
+        return ($query->execute()?->fetchColumn() ?? 0) > 0;
+    }
+
     /**
      * Get random object
      *