Fixed the docblocks for class properties

src/Database/Type/BinaryType.php

@@ -31,7 +31,7 @@ class BinaryType implements TypeInterface
     /**
      * Identifier name for this type
      *
-     * @var string
+     * @var string|null
      */
     protected $_name = null;
 

src/Database/Type/BoolType.php

@@ -30,7 +30,7 @@ class BoolType implements TypeInterface
     /**
      * Identifier name for this type
      *
-     * @var string
+     * @var string|null
      */
     protected $_name = null;
 

src/Database/Type/DateTimeType.php

@@ -80,7 +80,7 @@ class DateTimeType implements TypeInterface
     /**
      * Identifier name for this type
      *
-     * @var string
+     * @var string|null
      */
     protected $_name = null;
 

src/Database/Type/FloatType.php

@@ -30,7 +30,7 @@ class FloatType implements TypeInterface
     /**
      * Identifier name for this type
      *
-     * @var string
+     * @var string|null
      */
     protected $_name = null;
 

src/Database/Type/IntegerType.php

@@ -30,7 +30,7 @@ class IntegerType implements TypeInterface
     /**
      * Identifier name for this type
      *
-     * @var string
+     * @var string|null
      */
     protected $_name = null;