Concise call method for RequireRecentData() subroutine

[JohnathonStoneMS]

If you want to check the recency of data before using that data to create a mapping table, you have to first load it into a non-mapping table. Then, you have to call the data recency subroutine and drop the temp table.

Example code:

[Data Recency Check]:
Load
    Min([Data Source Access Time]) AS [Data Source Access Time]
From [lib://Warehouse - Extracts/Foo.qvd] (qvd)
;

Let vIncludePath = 'lib://Qlik Utility Library/RequireRecentData.qvs';
$(Must_Include=$(vIncludePath));
Call RequireRecentData('Data Recency Check', 'Data Source Access Time', vDataRecencyThreshold, vAllowStaleData);

Drop Table [Data Recency Check];

Since these tables are usually named Data Recency Check and the metadata field containing the access timestamp is usually named Data Source Access Time, you should be able to invoke the policy by providing only the data source file path.

Desired call structure:

Let vSourceQVDPath = 'lib://Warehouse - Extracts/Foo.qvd';
Call RequireRecentDataFromQVD(vSourceQVDPath);

In this shorter-form call, the invoked subroutine will make use of environmental variables: vDataRecencyThreshold and vAllowStaleData. By default, the environment-wide configuration system controls the values of these variables. They can also be overwritten at the app-level. Finally, it would automatically use the table name, Data Recency Check, and assume the timestamp field name is Data Source Access Time.

The new subroutine, RequireRecentDataFromQVD(), should invoke RequireRecentData().

One last request: an optional 2nd parameter, an override value for the timestamp field name, to allow use of the concise call method when the timestamp field has been aliased.