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 SET SCOPETOP
 Set the top index SCOPE value
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 Syntax

     SET SCOPETOP TO [<value>]

     <value> specifies the upper index key value of the current index to
     which to view a subset of records.  An upper boundary value, denoted
     as TOP, is used to establish the upper range of visible records
     within the current index.

     If <value> is omitted, the TOP scope is cleared and the actual top of
     the index is assumed.  For example, if SET SCOPETOP is the only scope
     defined, the visible index records will start at the TOP scope value
     and proceed to the end of the index file.

 Description

     SET SCOPETOP is used to set the TOP scope to specific index key
     values.  The value determines the upper limit by which to view the
     index records.  SET SCOPETOP sets the starting key value (inclusive).
     The SCOPE commands are designed to emulate the actual TOP and BOTTOM
     of the current index.  This means descending indexes will have a
     higher SCOPETOP than SCOPEBOTTOM value.

     Advantage SCOPE commands and functions allow you to view a subset of
     records in an index. Bottom and top index key limits are defined to
     retrieve only those records that fit within the specified SCOPE range.
     The range acts as a temporary view of an index, allowing rapid
     retrieval of only those records meeting the SCOPE range value(s).  The
     range values are determined based on the current index.

     The specified scope is active as soon as the record pointer is
     repositioned using GO TOP, GO BOTTOM, SEEK or SKIP commands.  Using
     the GOTO command will allow the record pointer to be positioned
     outside the defined scope.

     Scopes exist per index order. That is, each index order in each work
     area can have its own scope. Only the scope on the currently active
     index order in the currently active work area is in effect, however.
     Scopes continue to exist until the scope is cleared (using
     CLEAR SCOPE) or the corresponding index is closed. Changing active
     index orders and/or work areas does not clear a scope; it just changes
     what scope is in effect.

     Advantage SCOPE commands are not to be confused with CA-Clipper
     <scopes>.  Advantage SCOPES are used to view a subset of records in
     an existing index; CA-Clipper <scopes> are used to build a new index
     based upon a subset of table records.

     Note:  If both a narrow SCOPE and a narrow FILTER (narrow meaning
     that only a small percentage of the total records in the table match
     the SCOPE and FILTER conditions) are being used in the same work area,
     poor performance may result.  Since knowledge of SCOPEs is ONLY on
     the client, and since FILTERs are handled on the server, the
     filtering of records on the server may unnecesssarily traverse
     through the index well beyond one of the SCOPE boundaries, thus,
     leading to poor performance.  If this is occurring, it is recommended
     to use either a SCOPE or a FILTER, but not both in the same work area.

 Example

     #include "DBFCDXAX.CH"

     USE test VIA "DBFCDXAX"

     INDEX ON age TAG age         // Create and index on the AGE field

     SET SCOPETOP TO 21           // Sets the top SCOPE value to 21
     SET SCOPEBOTTOM TO 30        // Sets the bottom SCOPE value to 30

     Browse()                     // Browse records within the scope

     CLEAR SCOPE                  // Clears the SCOPE