diff --git a/resources/schema/inventory.xsd b/resources/schema/inventory.xsd
index 1b94a52..a145ab4 100644
--- a/resources/schema/inventory.xsd
+++ b/resources/schema/inventory.xsd
@@ -535,7 +535,7 @@
       <xsd:element name="form" type="formType"/>
       <xsd:element name="measureList" type="measureListType" minOccurs="0"/>
     </xsd:sequence>
-    <xsd:attribute name="id" type="xsd:integer" use="required"/>
+    <xsd:attribute name="id" type="xsd:integer"/>
     <xsd:attribute name="morphologyPatterns" type="xsd:string"/>
     <xsd:attribute name="status" type="xsd:string"/>
     <xsd:attribute name="norm" type="xsd:string"/> <!-- closed set? -->
@@ -552,8 +552,8 @@
       <xsd:element name="form" type="formType"/>
       <xsd:element name="measureList" type="measureListType" minOccurs="0"/>
     </xsd:sequence>
-    <xsd:attribute name="id" type="xsd:integer" use="required"/>
-    <xsd:attribute name="orthography_id" type="xsd:integer" use="required"/>
+    <xsd:attribute name="id" type="xsd:integer"/>
+    <xsd:attribute name="orthography_id" type="xsd:integer"/>
     <xsd:attribute name="stressPatterns" type="xsd:string"/> 
     <xsd:attribute name="status" type="xsd:string"/> 
     <xsd:attribute name="norm" type="xsd:string"/>
@@ -590,8 +590,8 @@
       <xsd:element name="form" type="pronunciationFormType" maxOccurs="unbounded"/>
       <xsd:element name="measureList" type="measureListType" minOccurs="0"/>
     </xsd:sequence>
-    <xsd:attribute name="id" type="xsd:integer" use="required"/>
-    <xsd:attribute name="dynamic_accentuation_id" type="xsd:integer" use="required"/>
+    <xsd:attribute name="id" type="xsd:integer"/>
+    <xsd:attribute name="dynamic_accentuation_id" type="xsd:integer"/>
     <xsd:attribute name="tonemic_accentuation_id" type="xsd:integer"/>
     <xsd:attribute name="status" type="xsd:string"/> 
     <xsd:attribute name="norm" type="xsd:string"/>
@@ -608,8 +608,8 @@
       <xsd:element name="form" type="formType"/>
       <xsd:element name="measureList" type="measureListType" minOccurs="0"/>
     </xsd:sequence>
-    <xsd:attribute name="id" type="xsd:integer" use="required"/>
-    <xsd:attribute name="orthography_id" type="xsd:integer" use="required"/>
+    <xsd:attribute name="id" type="xsd:integer"/>
+    <xsd:attribute name="orthography_id" type="xsd:integer"/>
   </xsd:complexType>
 
   <xsd:complexType name="hyphenationListType">
@@ -625,7 +625,7 @@
       <xsd:element name="grammarFeatureList" type="grammarFeatureListType" minOccurs="0"/>
       <xsd:element name="formRepresentations" type="formRepresentationsType"/>
     </xsd:sequence>
-    <xsd:attribute name="id" type="xsd:int" use="required"/>
+    <xsd:attribute name="id" type="xsd:int"/>
   </xsd:complexType>
 
   <!-- List of word forms -->