Add retrieval of jdbc types as string

src/main/java/org/polypheny/jdbc/types/TypedValue.java

@@ -567,7 +567,7 @@ public String asString() throws SQLException {
             case LIST:
             case FILE:
             case DOCUMENT:
-                return otherValue.toString();
+                throw new PrismInterfaceServiceException( PrismInterfaceErrors.DATA_TYPE_MISMATCH, "This value cannot be returned as a string." );
         }
         throw new PrismInterfaceServiceException( PrismInterfaceErrors.DATA_TYPE_MISMATCH, "This value cannot be returned as a string." );
     }
@@ -1459,4 +1459,47 @@ private static PolyInterval getInterval( ProtoInterval interval ) {
         return new PolyInterval( interval.getMonths(), interval.getMilliseconds() );
     }
 
+
+    @Override
+    public String toString() {
+        if ( isSerialized ) {
+            deserialize();
+        }
+        switch ( valueCase ) {
+            case BOOLEAN:
+                return "" + booleanValue;
+            case INTEGER:
+                return "" + integerValue;
+            case LONG:
+                return "" + bigintValue;
+            case BIG_DECIMAL:
+                return "" + bigDecimalValue;
+            case FLOAT:
+                return "" + floatValue;
+            case DOUBLE:
+                return "" + doubleValue;
+            case DATE:
+                return "" + dateValue;
+            case TIME:
+                return "" + timeValue;
+            case TIMESTAMP:
+                return "" + timestampValue;
+            case INTERVAL:
+                return "" + otherValue;
+            case STRING:
+                return varcharValue;
+            case BINARY:
+                return "BINARY";
+            case NULL:
+                return "NULL";
+            case LIST:
+                return "LIST";
+            case FILE:
+                return "FILE";
+            case DOCUMENT:
+                return "DOCUMENT";
+        }
+        return "";
+    }
+
 }