diff --git a/src/db/Validator.ts b/src/db/Validator.ts
index e76ed9a..85ca6b8 100644
--- a/src/db/Validator.ts
+++ b/src/db/Validator.ts
@@ -86,6 +86,30 @@ export default class Validator<T> {
         return this;
     }
 
+    /**
+     * @param minLength included
+     */
+    public minLength(minLength: number): Validator<T> {
+        this.addStep({
+            verifyStep: val => (<any>val).length >= minLength,
+            throw: () => new BadLengthValidationError(minLength, 1000000),
+            isFormat: true,
+        });
+        return this;
+    }
+
+    /**
+     * @param maxLength included
+     */
+    public maxLength(maxLength: number): Validator<T> {
+        this.addStep({
+            verifyStep: val => (<any>val).length <= maxLength,
+            throw: () => new BadLengthValidationError(0, maxLength),
+            isFormat: true,
+        });
+        return this;
+    }
+
     /**
      * @param minLength included
      * @param maxLength included