DBRUNLOCK()
 Release all or specified record locks
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 Syntax

     DBRUNLOCK([<xIdentity>]) --> NIL

 Arguments

     <xIdentity> is a unique value guaranteed by the structure of the
     data file to reference a specific item in a data source (database).  In
     a .dbf <xIdentity> is the record number.  In other data formats,
     <xIdentity> is the unique primary key value.

 Returns

     DBRUNLOCK() always returns NIL.

 Description

     DBRUNLOCK() is a database function that releases the lock on <xIdentity>
     and removes it from the Lock List.  If <xIdentity> is not specified, all
     record locks are released.

 Examples

     PROCEDURE dbRUnlockRange( nLo, nHi )

        LOCAL nCounter

        // Unlock the records in the range from nLo to nHi
        FOR nCounter := nLo TO nHi
           DBRUNLOCK( nCounter )
        NEXT

        RETURN