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  • Re: Awk and RDBMS

    From Janis Papanagnou@21:1/5 to Mr. Man-wai Chang on Fri Mar 1 18:25:26 2024
    On 01.03.2024 17:29, Mr. Man-wai Chang wrote:

    Can Awk directly interact with some RDBMS engine (that is, within
    'BEGIN{}')?

    It depends on the interface the RDBMS provides.

    What you can do with GNU awk is, for example, to create a co-process
    and send requests to that co-process and intercept its replies to
    process them.

    Janis

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  • From Janis Papanagnou@21:1/5 to Mr. Man-wai Chang on Sun Mar 3 16:28:09 2024
    On 03.03.2024 11:16, Mr. Man-wai Chang wrote:
    On 2/3/2024 1:25 am, Janis Papanagnou wrote:

    It depends on the interface the RDBMS provides.

    What you can do with GNU awk is, for example, to create a co-process
    and send requests to that co-process and intercept its replies to
    process them.
    I suppose it's the only solution, unless you extend Awk's syntax to SQLconnect some RDBMS. :)

    Well, in the past there was xgawk that supported database handling.
    This feature is now available in GNU Awk as part of its extension
    library. You can handle PostgreSQL with it. But since I have never
    used it myself you have to look up the details yourself. (Or maybe
    there's someone around here who has experiences with the extension
    or can answer any specific questions.)

    Janis

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  • From Arti F. Idiot@21:1/5 to Mr. Man-wai Chang on Sun Mar 3 15:20:41 2024
    On 3/1/24 9:29 AM, Mr. Man-wai Chang wrote:

    Can Awk directly interact with some RDBMS engine (that is, within
    'BEGIN{}')?

    I haven't done a Google Search yet. Is looking for a direct answer. :)

    I *think* most SQL type DBs have CLI interaction capabilities.

    A SQLite3 example; 'csv' used for DB output mode since it's easy to run
    split() on and several awks now have native CSV support:

    --
    $ sqlite3 -header -column site.db 'select * from site'
    Station SSID CHAN
    ---------- ---------- ----------
    1 CIA 9
    2 FBI 11
    3 NSA 1
    4 DOD 10

    $ cat site.awk
    BEGIN {
    DBfile = "./site.db"
    CMD = "sqlite3 -csv " DBfile " \"" ARGV[1] "\""
    while (CMD | getline == 1) arr[++cnt] = $0
    close(CMD)
    for (i=1; i<=cnt; i++) printf "arr[%d] = %s\n", i, arr[i]
    print ""
    }

    $ nawk -f site.awk 'select * from site'
    arr[1] = 1,CIA,9
    arr[2] = 2,FBI,11
    arr[3] = 3,NSA,1
    arr[4] = 4,DOD,10

    $ nawk -f site.awk 'select SSID from site'
    arr[1] = CIA
    arr[2] = FBI
    arr[3] = NSA
    arr[4] = DOD

    --

    This is just read-only of course; would need to use gawk for fancier things.

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  • From Grant Taylor@21:1/5 to Arti F. Idiot on Mon Mar 4 10:49:00 2024
    On 3/3/24 16:20, Arti F. Idiot wrote:
    BEGIN {
      DBfile = "./site.db"
      CMD = "sqlite3 -csv " DBfile " \"" ARGV[1] "\""
      while (CMD | getline == 1) arr[++cnt] = $0
      close(CMD)
      for (i=1; i<=cnt; i++) printf "arr[%d] = %s\n", i, arr[i]
      print ""
    }

    Would someone please help me understand why you'd want to have the
    sqlite3 (et al.) inside of awk (in the BEGIN{...}) verses having sqlite3 outside of awk and piping the output from sqlite3's STDOUT into awk's STDIN?

    sqlite3 ... | awk ...



    --
    Grant. . . .

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  • From Kaz Kylheku@21:1/5 to Grant Taylor on Mon Mar 4 17:10:26 2024
    On 2024-03-04, Grant Taylor <gtaylor@tnetconsulting.net> wrote:
    On 3/3/24 16:20, Arti F. Idiot wrote:
    BEGIN {
      DBfile = "./site.db"
      CMD = "sqlite3 -csv " DBfile " \"" ARGV[1] "\""
      while (CMD | getline == 1) arr[++cnt] = $0
      close(CMD)
      for (i=1; i<=cnt; i++) printf "arr[%d] = %s\n", i, arr[i]
      print ""
    }

    Would someone please help me understand why you'd want to have the
    sqlite3 (et al.) inside of awk (in the BEGIN{...}) verses having sqlite3 outside of awk and piping the output from sqlite3's STDOUT into awk's STDIN?

    1. You could just have a #!/usr/bin/awk -f script instead of
    a #!/bin/sh script that calls awk.

    2. That script's standard input is available for other use. For
    it could process the sqlite file to populate the array in the
    above way, and then process standard input with the help of that
    array.

    --
    TXR Programming Language: http://nongnu.org/txr
    Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
    Mastodon: @Kazinator@mstdn.ca

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