Tucker Watson

Sometimes the batch editor doesn’t cut it and I’m required to write a program to interact with a certain type of component. I could write a robot to traverse through the nav tree but I usually use a BQL query to do the work. The following is a method I often use to grab an Array of BObjects for a given BQL query.

public BObject[] getObjectsFromBql(String bqlString)
{   
   BOrd curOrd;
 
   // Grab reference to local station
   BStation station = (BStation) BOrd.make("station:|slot:/").get();
 
   // Run the BQL query and get the resulting table
   BITable result = (BITable) BOrd.make(bqlString).get(station);
 
   ColumnList columns = result.getColumns();
 
   // Note we're assuming column 0 is "slotPath"     
   Column slotPathColumn = columns.get(0);
   TableCursor c = (TableCursor) result.cursor();
 
   // Create the Array of BObjects to return
   BObject[] objs = new BObject[result.size()];
 
   int i = 0;
   while (c.next())
   {      
      curOrd = BOrd.make(c.get(slotPathColumn).toString());
 
      // Resolve each ord to a BObject, store in our Array
      objs[i++] = (BObject)curOrd.resolve(station).get();
   }
 
   return objs;   
}

Example to get an Array of all BStatusNumerics in ‘fault’:


getObjectsFromBql("select slotPath from baja:StatusNumeric where status.isFault")


Note: You must specify ’slotPath’ as the first column in the query

Tucker Niagara BQL, Niagara

One of the most powerful but underutilized features of Niagara AX is BQL queries. John Sublett wrote an excellent post on Niagara-Central called BQL Demystified - Part I that covers basic syntax and meaning. This post will extend John’s post by demonstrating the Query Builder, running custom queries, and other examples.

The example we’re going to try is how to view the name of all Numeric Points whose name starts with “SpaceTemp”. Open the Query Builder (File>Open>Query Builder) and configure it as shown below.

Example of input data for a Niagara AX BQL Query

After pressing OK you’ll get a table wtih the resulting query.  To view the generated query, hold CTRL and press L (this shows your current ORD).  You should see somethign similar to this:

station:|slot:/|bql:select navOrd from control:NumericPoint where name = 'SpaceTemp'

The cool part is that you can write and run your own query by copying it into the Open Ord dialog (CTRL+L).

More Examples:

Tucker Niagara AX, BQL, Niagara