QMSelectPartial()

QMSelectPartial()

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The QMSelectPartial() function generates a select list containing the ids of all records in a file using an optimised method for improved performance. It is analogous to use of the QMBasic SELECT statement.

 

The function arguments are:

 

FileNois the file number returned by a previous QMOpen() call.

 

ListNois the select list number (0 to 10).

 

 

The QMSelectPartial() function constructs a list of record ids in the file open as FileNo. The first part of the select list is returned as a field mark delimited string. Further items can then be returned by use of the QMNextPartial() function until this returns a null string to indicate that there are no further record ids available.

 

See Select lists in QMClient sessions for a description of the alternative ways to handle select list with QMClient.

 

Select list 0, the default select list, is used automatically by many QM components to control their action and should, therefore, be used with caution. An unwanted or partially processed select list can be cleared using the QMClearSelect() function.

The QMSelectPartial() function does not provide any method to select only those records that meet specific conditions or to sort the list. These features can be accessed by executing query processor commands using the QMExecute() function.

 

The example program fragments below build select list 1 and use it to process records from the file open as fClients.

 

 

hmtoggle_plus1C

 

hmtoggle_plus1VB.Net

 

hmtoggle_plus1QMBasic Class Module

 

hmtoggle_plus1Java

 

hmtoggle_plus1Python