rdcat (1) --- concatenate two identical relations 08/03/81 _U_s_a_g_e rdcat _D_e_s_c_r_i_p_t_i_o_n 'Rdcat' is part of the toy relational data base system, 'rdb'. It creates a new relation by concatenating the two relations specified as standard inputs 1 and 2 and writes the new relation on standard output 1. Both relations must have identical descriptions -- the domains must be identical and in the same order. The input relations must be files containing relations that were created by 'rdmake'; relations cannot be read from the terminal. The output relation is displayed in a readable format if standard output is directed to a terminal (display in binary would be quite a mess); otherwise, the output relation is written in binary, internal format for proces- sing by other 'rdb' programs. Identical tuples are not removed from the resulting relations. These can be removed using 'rdsort' and 'rduniq'. _E_x_a_m_p_l_e_s p1.rel> p2.rel> rdcat >p.rel p.des> newp.data> rdmake | p.rel> rdcat >newp.rel _M_e_s_s_a_g_e_s "Sorry, a relation can't be read from the terminal" "Relation is corrupted!!" "Can't access input relation 1" "Can't access input relation 2" "Relations must have identical descriptions" _B_u_g_s It would be nice if the relations only had to have the same structure to be concatenated. If standard output is directed to "/dev/lps", the relation is written in binary. _S_e_e _A_l_s_o rdcat (1), rdextr (1), rdjoin (1), rdmake (1), rdprint (1), rdproj (1), rdsel (1), rdsort (1), rduniq (1) rdcat (1) - 1 - rdcat (1)