isIdCurrent              package:RMySQL              R Documentation

_C_h_e_c_k _w_h_e_t_h_e_r _a _d_a_t_a_b_a_s_e _h_a_n_d_l_e _o_b_j_e_c_t _i_s _v_a_l_i_d _o_r _n_o_t

_D_e_s_c_r_i_p_t_i_o_n:

     Support function that verifies that an object holding a reference
     to a foreign object is still valid for communicating with the
     RDBMS

_U_s_a_g_e:

     isIdCurrent(obj)

_A_r_g_u_m_e_n_t_s:

     obj: any 'dbObject' (e.g., 'dbDriver', 'dbConnection',
          'dbResult'). 

_D_e_t_a_i_l_s:

     'dbObjects' are R/S-Plus remote references to foreign objects.
     This introduces differences to the object's semantics such as
     persistence (e.g., connections may be closed unexpectedly), thus
     this function provides a minimal verification to ensure  that the
     foreign object being referenced can be contacted.

_V_a_l_u_e:

     a logical scalar.

_S_e_e _A_l_s_o:

     'dbDriver' 'dbConnect' 'dbSendQuery' 'fetch'

_E_x_a_m_p_l_e_s:

     ## Not run: 
     cursor <- dbSendQuery(con, sql.statement)
     isIdCurrent(cursor)
     ## End(Not run)

