docs: add example for displaying field inheritance in ServiceNow tables (#2199)

Author: andrey-verevkin

Core ServiceNow APIs/GlideElement/Display base table for each field/README.md

@@ -0,0 +1,32 @@
+# Display Base Table for Each Field
+
+This code snippet demonstrates how to identify the base table where each field originates from in ServiceNow's table inheritance hierarchy.
+
+## Functionality
+
+The script uses `GlideRecordUtil` to retrieve all parent tables for a given table, then iterates through each field in a record to display which base table the field was defined in using the `getBaseTableName()` method from the GlideElement API.
+
+## Use Case
+
+This is particularly useful when working with extended tables to understand:
+- Which fields are inherited from parent tables
+- Which fields are defined locally on the current table
+- The complete table inheritance structure
+
+## Example Output
+
+For a table like `db_image`, the output shows each field name alongside its originating table:
+```
+Fields          Base table
+sys_id          sys_metadata
+sys_created_on  sys_metadata
+image           db_image
+name            db_image
+...
+```
+
+## Related Methods
+
+- `getBaseTableName()` - Returns the name of the table where the field was originally defined
+- `GlideRecordUtil.getTables()` - Returns parent tables in the inheritance hierarchy
+- `GlideRecordUtil.getFields()` - Returns an array of all field names for a GlideRecord

Core ServiceNow APIs/GlideElement/Display base table for each field/displayBaseTablesForEachField.js

@@ -0,0 +1,19 @@
+var tableName = 'db_image';
+
+var gru = new GlideRecordUtil();
+
+var parentTables = gru.getTables(tableName);
+gs.print("Parent tables: " + parentTables);
+
+var gr = new GlideRecord(tableName);
+gr.setlimit(1);
+gr.query();
+
+if(gr.next()){ 
+	var fieldNames = gru.getFields(gr);
+	gs.print('Fields\t\tBase table');
+    for (var i = 0; i < fieldNames.length; i++) {
+		gs.print(fieldNames[i] + "\t\t" + gr[fieldNames[i]].getBaseTableName()); 
+    }
+}
+