diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Storage.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Storage.java
index 41740d108..b66975343 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Storage.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Storage.java
@@ -3,16 +3,17 @@ package org.hl7.fhir.r5.utils.sql;
 import java.util.List;
 
 import org.hl7.fhir.r5.model.Base;
+import org.hl7.fhir.r5.utils.sql.Validator.TrueFalseOrUnknown;
 
 public interface Storage {
 
-  boolean supportsArrays();
-  boolean supportsComplexTypes();
+  TrueFalseOrUnknown supportsArrays();
+  TrueFalseOrUnknown supportsComplexTypes();
   
   Store createStore(String name, List<Column> columns);
   void addRow(Store store, List<Cell> cells);
   void finish(Store store);
-  boolean needsName();
+  TrueFalseOrUnknown needsName();
   String getKeyForSourceResource(Base res);
   String getKeyForTargetResource(Base res);
 }
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageJson.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageJson.java
index d76404c03..9581118c3 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageJson.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageJson.java
@@ -4,6 +4,7 @@ import java.util.List;
 
 import org.hl7.fhir.exceptions.FHIRException;
 import org.hl7.fhir.r5.model.Base;
+import org.hl7.fhir.r5.utils.sql.Validator.TrueFalseOrUnknown;
 import org.hl7.fhir.utilities.json.model.JsonArray;
 import org.hl7.fhir.utilities.json.model.JsonBoolean;
 import org.hl7.fhir.utilities.json.model.JsonElement;
@@ -18,8 +19,8 @@ public class StorageJson implements Storage {
   private JsonArray rows;
   
   @Override
-  public boolean supportsArrays() {
-    return true;
+  public TrueFalseOrUnknown supportsArrays() {
+    return TrueFalseOrUnknown.TRUE;
   }
 
   @Override
@@ -77,13 +78,13 @@ public class StorageJson implements Storage {
   }
 
   @Override
-  public boolean supportsComplexTypes() {
-    return true;
+  public TrueFalseOrUnknown supportsComplexTypes() {
+    return TrueFalseOrUnknown.TRUE;
   }
 
   @Override
-  public boolean needsName() {
-    return false;
+  public TrueFalseOrUnknown needsName() {
+    return TrueFalseOrUnknown.FALSE;
   }
 
   @Override
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageSqlite3.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageSqlite3.java
index 1a32d9c46..4fddf533d 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageSqlite3.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/StorageSqlite3.java
@@ -7,6 +7,7 @@ import java.util.List;
 
 import org.hl7.fhir.exceptions.FHIRException;
 import org.hl7.fhir.r5.model.Base;
+import org.hl7.fhir.r5.utils.sql.Validator.TrueFalseOrUnknown;
 import org.hl7.fhir.utilities.CommaSeparatedStringBuilder;
 
 public class StorageSqlite3 implements Storage {
@@ -119,18 +120,18 @@ public class StorageSqlite3 implements Storage {
   }
 
   @Override
-  public boolean supportsArrays() {
-    return false;
+  public TrueFalseOrUnknown supportsArrays() {
+    return TrueFalseOrUnknown.FALSE;
   }
 
   @Override
-  public boolean supportsComplexTypes() {
-    return false;
+  public TrueFalseOrUnknown supportsComplexTypes() {
+    return TrueFalseOrUnknown.FALSE;
   }
 
   @Override
-  public boolean needsName() {
-    return true;
+  public TrueFalseOrUnknown needsName() {
+    return TrueFalseOrUnknown.TRUE;
   }
 
   @Override
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Validator.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Validator.java
index 00c862b5d..13c132962 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Validator.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/sql/Validator.java
@@ -32,6 +32,7 @@ import org.hl7.fhir.r5.model.UnsignedIntType;
 import org.hl7.fhir.r5.model.UriType;
 import org.hl7.fhir.r5.model.UrlType;
 import org.hl7.fhir.r5.model.UuidType;
+import org.hl7.fhir.r5.utils.sql.Validator.TrueFalseOrUnknown;
 import org.hl7.fhir.r5.fhirpath.ExpressionNode.CollectionStatus;
 import org.hl7.fhir.r5.fhirpath.FHIRPathEngine.IssueMessage;
 import org.hl7.fhir.utilities.Utilities;
@@ -49,18 +50,22 @@ import org.hl7.fhir.utilities.validation.ValidationMessage.Source;
 
 public class Validator {
 
+  public enum TrueFalseOrUnknown {
+    TRUE, FALSE, UNKNOWN
+  }
+
   private IWorkerContext context;
   private FHIRPathEngine fpe;
   private List<String> prohibitedNames = new ArrayList<String>();
   private List<ValidationMessage> issues = new ArrayList<ValidationMessage>();
-  private Boolean arrays;
-  private Boolean complexTypes;
-  private Boolean needsName;
+  private TrueFalseOrUnknown arrays;
+  private TrueFalseOrUnknown complexTypes;
+  private TrueFalseOrUnknown needsName;
 
   private String resourceName;
   private String name;
 
-  public Validator(IWorkerContext context, FHIRPathEngine fpe, List<String> prohibitedNames, Boolean arrays, Boolean complexTypes, Boolean needsName) {
+  public Validator(IWorkerContext context, FHIRPathEngine fpe, List<String> prohibitedNames, TrueFalseOrUnknown arrays, TrueFalseOrUnknown complexTypes, TrueFalseOrUnknown needsName) {
     super();
     this.context = context;
     this.fpe = fpe;
@@ -82,7 +87,7 @@ public class Validator {
     if (nameJ == null) {
       if (needsName == null) {
         hint(path, viewDefinition, "No name provided. A name is required in many contexts where a ViewDefinition is used");        
-      } else if (needsName) {
+      } else if (needsName == TrueFalseOrUnknown.TRUE) {
         error(path, viewDefinition, "No name provided", IssueType.REQUIRED);
       }
     } else if (!(nameJ instanceof JsonString)) {
@@ -334,9 +339,9 @@ public class Validator {
                 hint(path, column, "collection is true, but the path statement(s) can only return single values for the column '"+columnName+"'");
               }
             } else {
-              if (arrays == null) {
+              if (arrays == TrueFalseOrUnknown.UNKNOWN) {
                 warning(path, expression, "The column '"+columnName+"' appears to be a collection based on it's path. Collections are not supported in all execution contexts");
-              } else if (!arrays) {
+              } else if (arrays == TrueFalseOrUnknown.FALSE) {
                 warning(path, expression, "The column '"+columnName+"' appears to be a collection based on it's path, but this is not allowed in the current execution context");
               }
               if (td.getCollectionStatus() != CollectionStatus.SINGLETON) {
@@ -373,9 +378,9 @@ public class Validator {
               String type = types.iterator().next();
               boolean ok = false;
               if (!isSimpleType(type) && !"null".equals(type)) {
-                if (complexTypes) {
+                if (complexTypes == TrueFalseOrUnknown.UNKNOWN) {
                   warning(path, expression, "Column is a complex type. This is not supported in some Runners");
-                } else if (!complexTypes) {            
+                } else if (complexTypes == TrueFalseOrUnknown.FALSE) {            
                   error(path, expression, "Column is a complex type but this is not allowed in this context", IssueType.BUSINESSRULE);
                 } else {
                   ok = true;