class %Library.ScrollableResultSet
extends %Library.ResultSet
This provides a scrollable resultset object that can also be saved and loaded
It works by running the entire query when the first item of data is requested
and storing the results in a global. Then you can move around the results by setting the
CurrRow and you may also call Previous as
well as the standard Next. In addition you may save this resultset
and then load it potentially in a different process at a later date and continue
reading from it, for example:
Set results=##class(%ScrollableResultSet).%New("Classname:QueryName")
Do results.Execute()
Do results.Next()
Write results.Data("fieldname")
Do results.%Save()
Set id=results.%Id()
Kill results
Set results=##class(%ScrollableResultSet).%OpenId(id)
Do results.Next()
Write results.Data("fieldname")
Note that if you open a %ScrollableResultSet and do not call %Save on it then when you
close this object the data stored in the global will be removed and so you will not be
able to open this resultset again. So if you open a scrollable resultset and you wish
to use this again call %Save on it, but you must always make sure that when you are finished
with it you do not call %Save so the temporary global used is cleaned up when you are done.
Alterntively you can call %DeleteId passing the id to remove the saved data.
There is also a Count to find the total number of entries in this resultset.
• property CurrRow
as %Integer;
Number of current row in the temp table, you can set this property to
move to a new location and also use this to check the current position.
If you specify a value that is out of bounds then the row will not be moved.
The first row is at CurrRow=1, so it is 1 based and not 0 based.
• property MaxRows
as %Integer [ InitialExpression = 0 ];
This determines how many rows this query will load, the default '0' will load
all the results, if you set it to 10,000 then it will only load the first 10,000
rows, which will mean you can not access any data beyond the 10,000th element.
Also the actual stopping point may be slightly larger than MaxRows because of the
way the data is imported, but it will be around this figure.
• classmethod %DeleteId(id As %String, concurrency As %Integer = -1)
as %Status
• final method %Id()
as %String
• classmethod %OpenId(id As %String, concurrency As %Integer = -1, ByRef sc As %Status = $$$OK)
as %ObjectHandle
• method %Save()
as %Status
• method Count()
as %Integer
Returns the number of rows contained in this ResultSet.
• method CurrRowSet(val As %String)
as %Status
This is a Set accessor method for the CurrRow property.
• method Load(id As %String)
as %Status
• method Next(ByRef sc As %Status)
as %Integer
Advance the result set cursor to the next row. Returns 0 if the cursor is at the end of the
result set.
• method Previous(ByRef sc As %Status)
as %Integer
Advance the result set cursor to the previous row. Returns 0 if the cursor is at the end of the
result set.
