SET RELATION

    SET RELATION links two open database files according to a key
    expression, record number, or numeric expression.

Syntax

    SET RELATION [ADDITIVE] TO [<key exp1>/RECNO()/<expN1>
    INTO <alias1>/<expC1>] [,TO <key exp2>/RECNO()/<expN2>
    INTO <alias2>/<expC2>]...

Arguments

    <key exp> is an expression used to perform a SEEK in the child work
    area each time the record pointer moves in the parent work area.  For
    this to work, the child work area must have an index in USE.

    RECNO() relates the parent to the child work area using the parent
    record number to perform a GOTO to the same record number in the child
    work area each time the record pointer moves in the parent work area.
    For this type of relation, it is recommended that the child work area
    not have an index in USE.

    <expN> is an expression used to perform a GOTO to the matching record
    number in the child work area each time the record pointer moves in the
    parent work area.  For this type of relation to execute correctly, the
    child work area must not have an index in USE.

    <alias> identifies the child work area.

    To release all RELATIONs in a work area, specify SET RELATION TO with
    no arguments.

    Clipper supports eight relations per work area.  Note that cyclical
    relations are not supported.  You cannot relate a database file to
    itself, either directly or indirectly.

Option

    Additive: The ADDITIVE clause adds the specified child relations to
    the relations already set in the current work area.  If this clause is
    not specified, existing relations in the current work area are released
    before the newly specified child relations are set.

Usage

    A relation defined by SET RELATION causes the record pointer to move in
    the child work area in accordance with the movement of the record
    pointer in the parent work area.  If there is not a match in the child
    work area, the child record pointer is positioned to LASTREC() + 1,
    EOF() returns true (.T.) and FOUND() returns false (.F.).

    Note: SET RELATION does not obey SOFTSEEK and always behaves as if
    SOFTSEEK is OFF.  If a match is not found in the child work area, the
    child record pointer is positioned to LASTREC() + 1.