The OracleDataAdapter
Requery
property controls whether or not queries are reexecuted for OracleDataAdapter
Fill
calls after the initial Fill
call.
The OracleDataAdapter
Fill
method allows appending or refreshing data in the DataSet
. When appending the DataSet
using the same query with subsequent Fill
calls, reexecuting the query may not be desirable.
When the Requery
property is set to true
, each subsequent Fill
call reexecutes the query and fills the DataSet
. This is an expensive operation, and if the reexecution is not required, set Requery
to false
. If any of the SelectCommand
properties or associated parameters must be changed, Requery
must be set to true
.
When the Requery
property is set to false
, the DataSet
has all the data as a snapshot at a particular time. The query is executed only for the first Fill
call; subsequent Fill
calls fetch the data from a cursor opened with the first execution of the query. This feature is supported only for forward-only fetches. Fill
calls that try to fetch rows before the last fetched row raise an exception. The connection used for the first Fill
call must be available for subsequent Fill
calls.
When filling a DataSet
with an OracleRefCursor
object, the Requery
property can be used in a similar manner. When the Requery
property is set to false
, both the connection used for the first Fill
call and the OracleRefCursor
object must be available for the subsequent Fill
calls.