alpha2 (#2)

- Change multiple field matching to enum
- Implement auto-generated IDs

Reviewed-on: #2

src/Exists.php

@@ -27,14 +27,14 @@ class Exists
      *
      * @param string $tableName The name of the table in which document existence should be determined
      * @param Field[] $fields The field comparison to match
-     * @param string $conjunction How to handle multiple conditions (optional; defaults to `AND`)
+     * @param FieldMatch|null $match How to handle multiple conditions (optional; defaults to All)
      * @return bool True if any documents match the field comparison, false if not
      * @throws DocumentException If any is encountered
      */
-    public static function byFields(string $tableName, array $fields, string $conjunction = 'AND'): bool
+    public static function byFields(string $tableName, array $fields, ?FieldMatch $match = null): bool
     {
         $namedFields = Parameters::nameFields($fields);
-        return Custom::scalar(Query\Exists::byFields($tableName, $namedFields, $conjunction),
+        return Custom::scalar(Query\Exists::byFields($tableName, $namedFields, $match),
             Parameters::addFields($namedFields, []), new ExistsMapper());
     }
 }