Using Result Sets
The EnsLib.SQL.GatewayResultSet class represents a special-purpose result set for use in InterSystems IRIS®. An initialized instance of this class has a live data connection to a data source. The class provides methods to examine the contents of the result set as well as a method to return a static snapshot.
This chapter describes how to use the EnsLib.SQL.GatewayResultSet class. It discusses the following:
How to get basic information about the result set
How to navigate the result set, row by row
How to get information about the current row of the result set
Note that you can also get a snapshot that contains rows from the result set; see “Using Snapshots.”
Creating and Initializing a Result Set
To create and initialize an SQL result set:
Use the ExecuteQuery() or the ExecuteQueryParmArray() method of the adapter. You will receive, by reference, an instance of EnsLib.SQL.GatewayResultSet.
If you just use the %New() class method, you can create a result set, but it will not be initialized and cannot contain any data. To initialize the result set, use the procedure described here.
Getting Basic Information about the Result Set
The following properties of EnsLib.SQL.GatewayResultSet provide basic information about a result set:
The ColCount property indicates the number of columns in the result set.
The QueryStatement property indicates the query statement used by this result set.
Examining the Current Row of the Result Set
Use the following methods to examine the current row of the result set:
method Get(pName As %String) returns %String
Returns the value of the column that has the name pName, in the current row.
method GetData(pColumn As %Integer) returns %String
Returns the value of the column whose position is specified by pColumn in the current row.
method GetColumnName(pColumn As %Integer = 0)
Returns the name of the column whose position is specified by pColumn.
If the source data contains any unnamed columns, the result set automatically provides names for these columns in the following form: xCol_n