IDataSourceValueTypeRequiredMetadataFieldNames Property

string[] RequiredMetadataFieldNames { get; }

ReadOnly Property RequiredMetadataFieldNames As String()
	Get

property array<String^>^ RequiredMetadataFieldNames {
	array<String^>^ get ();
}

abstract RequiredMetadataFieldNames : string[] with get

function get_RequiredMetadataFieldNames();

Property Value

This defines a list of the required metadata fields for a table in the data source. If any of these are missing, the data source table will not be available for use. This list should at least include key field names for the MetadataTableName that may be needed by the GetTargetIDSet(DataRow) or AssignToTimeValueMap(DataSourceValue, SortedListDouble, T, DataSet) functions. For example, in order to use a table named 'ActiveMeasurements', the required metadata field names might be: 'ID', 'SignalID', and 'PointTag'.

Note that system generally assumes that the fields 'PointTag', a unique string-based alphanumeric identifier for a measurement, 'ID', a unique string-based measurement key formatted identifier (e.g., PPA:101), and 'SignalID', a unique Guid-based identifier, all exist in the metadata table. However, these fields do not have to be included as required metadata field names. The 'PointTag' field is used to lookup records in the metadata. The 'ID' and 'SignalID' fields are used by 'AdapterBase.ParseFilterExpression' for direct parsing of measurement key and signal ID when expression is not a filter expression. Direct parsing always uses the primary metadata table name for lookups, see MetadataTableName property.

Reference