disabling bi-directional cursors.htm
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<title>Disabling bi-directional cursors</title>
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<p>Disabling bi-directional cursors<br>
<br>
Topic group<br>
<br>
The UniDirectional property determines whether or not BDE bi-directional cursors are
enabled for a query. When a query returns a result set, it also receives a cursor, or
pointer to the first record in that result set. The record pointed to by the cursor is the
currently active record. The current record is the one whose field values are displayed in
data-aware components associated with the result set抯 data source.<br>
UniDirectional is false by default, meaning that the cursor for a result set can navigate
both forward and backward through its records. Bi-directional cursor support requires some
additional processing overhead, and can slow some queries. To improve query performance,
you may be able to set UniDirectional to true, restricting a cursor to forward movement
through a result set.<br>
<br>
If you do not need to be able to navigate backward through a result set, you can set
UniDirectional to true for a query. Set UniDirectional before preparing and executing a
query. The following code illustrates setting UniDirectional prior to preparing and
executing a query:<br>
<br>
if not (CustomerQuery.Prepared) then begin<br>
<br>
CustomerQuery.UniDirectional := True;<br>
CustomerQuery.Prepare;<br>
end;<br>
CustomerQuery.Open; { returns a result set with a one-way cursor }<br>
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