Using Caché Objects - InterSystems Documentation

Using Objects with Caché ObjectScript
• GetParamName(n) returns a string specifying the name of the nth argument of the query.
• GetColumnCount returns an integer specifying the number of columns that the query
returns.
• GetColumnName(n) returns a string specifying the name of the nth column (field).
• GetColumnHeading(n) returns a string specifying the heading of the nth column (field).
10.7.2 Preparing Queries for Execution
To run a pre-defined class query, begin by instantiating a %ResultSet object as follows:
Set rset = ##class(%ResultSet).%New()
where rset is the OREF of the new %ResultSet object.
Having instantiated the %ResultSet object, the next task is to associate it with a particular
query in a particular class:
Set rset.ClassName = class
Set rset.QueryName = query
where rset is the OREF of the %ResultSet object, class is the name of the class containing
the query, and query is the name of the query to execute.
For example:
Set rset = ##class(%ResultSet).%New()
Set rset.ClassName = "Sample.Person"
Set rset.QueryName = "ByName"
Do rset.Execute()
While (rset.Next(.sc)) // go to the next row of the result set
{
If ($SYSTEM.Status.IsOK(sc)) // check if this succeeded without errors
{
Write rset.Data("Name"),! // perform busines logic
}
Else // if there was an error, break out of the While loop
{
Quit
}
}
If $SYSTEM.Status.IsError(sc) // if there was an error, process that
{
// perform error processing
}
You can also use the %ResultSet object to prepare a dynamic SQL statement using the Prepare
method:
84 Using Caché Objects