WIP: SELECT for GRPC API

src/main/java/org/caosdb/server/datatype/BooleanDatatype.java

@@ -32,6 +32,8 @@ public class BooleanDatatype extends AbstractDatatype {
   public SingleValue parseValue(final Object value) throws Message {
     if (value instanceof BooleanValue) {
       return (SingleValue) value;
+    } else if (value instanceof CollectionValue) {
+      throw ServerMessages.DATA_TYPE_DOES_NOT_ACCEPT_COLLECTION_VALUES;
     } else if (value instanceof SingleValue) {
       return parse(((SingleValue) value).toDatabaseString());
     } else {