Following instructions on this page https://docs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=D2IMP\_ch\_connector#D2IMP\_connector\_query_xdata I am trying to create a Data Connector to be used as a base class for a cube with update support. That page suggests that putting an SQL query inside XData block is not suitable for a Data Connector that supports updates. Later it also suggests that to enable updates your SQL query must include 
WHERE $$$RESTRICT
Providing an example of it in XData block example like this
<sql>SELECT A,B,C FROM MyApp.MyTable WHERE $$$RESTRICT</sql>
Which I already have a problem with, because earlier in that section it said _You cannot use this_ _technique _(regarding defining an SQL query inside XData block) _if the data connector must support detail listings or updates. In such cases, instead see “[Defining the Query at Runtime](https://docs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=D2IMP_ch_connector#D2IMP_connector_callback "Instead of defining a hardcoded query in an XData block, you can construct the query at runtime. If the data connector must support detail listings or updates, you must use this technique."),” later in this chapter._ However, the real problem for me is the use of $$$RESTRICT within string literal of an SQL query used for OnGetSourceResultSet. What would be a proper syntax here?