Rockwell Automation FactoryTalk Historian SE ProcessBook 3.2 User Guide - Manual (Page 275)

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defined in the order in which they are encountered in the SQL
statement.
13. Click Placeholders to check the syntax of the query. If the syntax is
not valid, the invalid query message is displayed.
14. Click OK.
Custom Data Sets
A custom data set is one provided through a VBA add-in to FactoryTalk
Historian ProcessBook. It is a COM object or a .NET object with a COM
wrapper that acts as an interface between FactoryTalk Historian
ProcessBook and the custom data provider. The source of data could be a
data store (like MS SQL Server) or a data calculation engine. FactoryTalk
Historian ProcessBook requests updates to the data every few seconds and
adjusts its display accordingly.
Before you can access custom data sets in a display, the Data Set add-in
must be installed and loaded through the Add-In Manager (page 13)
dialog box. Later, as you build a display, you select the data set and
column to be used for a symbol on a display through the symbol definition
dialog box boxes. Once a custom dataset is loaded, it is available
throughout the application. These data sets are not display or ProcessBook
specific.
Information on building a custom data set is beyond the scope of this
online help. It is discussed in Creating a Custom Data Set, a white paper
supplied with the FactoryTalk Historian ProcessBook software CD.
Placeholders
A Placeholder in an SQL query identifies a value that is to be provided
when the query is run. You can validate a query before the actual values
are provided.