Configure additional Business Logic Tier (BLT) components

Note: For information on overriding default configuration settings, see Modify configuration settings.

In addition to the stored procedures list in the previous sections, it is possible to extend the Microsoft SQL Engine to expose additional Business Logic Tier (BLT) components.

To expose additional BLTs for execution by the Microsoft SQL Engine, it is necessary to configure some basic information about the BLT in the Microsoft SQL Engine JSON hive. Each BLT must be named, associated with a AVEVA Enterprise SCADA service, and identified as belonging to a particular datastore. Here is the configuration for the base RealTime BLT components, as defined in the %DNADataRoot%\RealTime\config\Settings\SQLEngine_RealTime.json file:

{

"SQLEngine": {

"BLT": {

"RealTime": {

"NoResultSets": "\n\t\t\tRTDB.dbo.AddSYSalarm;\n\t\t\tRTDB.dbo.SpoolControl;\n\t\t\tRTDB.dbo.SpoolMsg\n\t\t",

"WithResultSets": "\n\t\t\tRTDB.dbo.Trend;\n\t\t\tRTDB.dbo.Trendview\n\t\t"

}

}

}

}

The hive must specify the AVEVA Enterprise SCADA service which must be running before the BLT is actually available: in the example above, it is the RealTime service.

The value definitions are divided into two categories based on what the BLTs return.

1. The BLT returns one or more sets of tabular data and is categorized as WithResultSet.

2. The BLT returns no tabular results (for example NoResultSets).

No special configuration is required to identify input or output parameters. This information will be obtained at run-time from the BLT service. Other points to note are:

• The naming convention for a fully-qualified BLT is <database>.<owner>.<name>. Thus the BLT components configured above are associated with the RTDB datastore.

• The string dbo stands for database owner.

• If the database or owner is not specified, the entry will default to SCHEMA and dbo, respectively.

• Multiple entries should be separated by a semi-colon.

• All whitespace between entries is ignored.

  Note: The stored procedure names are case-sensitive when being executed, however the name in the configuration file is not case-sensitive. If the case of the name in the configuration file is not correct, it will be fixed automatically when the Microsoft SQL Engine applies the configuration at run-time.