sqlFetch                package:RODBC                R Documentation

_R_e_a_d_i_n_g _T_a_b_l_e_s _f_r_o_m _O_D_B_C _D_a_t_a_b_a_s_e_s

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

     Read a table of an ODBC database into a data frame.

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

     sqlFetch(channel, sqtable, ..., colnames = FALSE, rownames = TRUE)

     sqlFetchMore(channel, ..., colnames = FALSE, rownames = TRUE)

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

 channel: connection handle returned by 'odbcConnect'.

 sqtable: a database table name accessible from the connected dsn. This
          should be either a character string or a character vector of
          length 1.

     ...: additional arguments to be passed to 'sqlGetResults'.

colnames: logical: retrieve column names from first row of table?

rownames: either logical or character. If logical, retrieve row names
          from the first column ('rownames') in the table?  If
          character, the column name to retrieve them.

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

     'sqlFetch' retrieves the the entire contents of the table
     'sqtable'.  Rownames and column names are restored as indicated.
     'sqlFetchMore' will retrieve further results from the query
     (provided there has been no other ODBC query on that channel in
     the meantime).

     It tries to cope with the peculiar way the Excel ODBC driver
     handles table names, and to quote Access table names which contain
     spaces.

     Useful additional parameters to pass to 'sqlGetResults' include

     '_m_a_x': limit on the number of rows to fetch, with 0 (the default)
          indicating no limit.

     '_n_u_l_l_s_t_r_i_n_g': character string to be used when reading
          'SQL_NULL_DATA' character items from the database.

     '_n_a._s_t_r_i_n_g_s': character string(s) to be mapped to 'NA' when
          reading character data.

     '_a_s._i_s': as in 'sqlGetResults'.

     '_d_e_c': The character for the decimal place to be assumed when
          converting character columns to numeric.

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

     A data frame on success, or a character or numeric error code (see
     'sqlQuery').

_N_o_t_e:

     If the table name desired is not a valid SQL name (alphanumeric
     plus '_'), use 'sqlQuery' with whatever quoting mechanism your
     DBMS vendor provides (e.g. '[ ]' on Microsoft products and
     backticks on recent versions of MySQL).

_A_u_t_h_o_r(_s):

     Michael Lapsley and Brian Ripley

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

     'sqlSave', 'sqlQuery', 'odbcConnect', 'odbcGetInfo'

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

     ## Not run: 
     data(USArrests) # R < 2.0.0 only
     channel <- odbcConnect("test")
     sqlSave(channel, USArrests, verbose = TRUE)
     sqlFetch(channel, "USArrests") # get the lot
     sqlFetch(channel, "USArrests", max=20)
     sqlFetchMore(channel, max=20)
     sqlFetchMore(channel) # get the rest
     sqlDrop(channel, "USArrests") 
     close(channel)
     ## End(Not run)

