Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW

Comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
If you're worried about unusual table names
Well, no - that's not my problem.
The problem is that I will not know the names of the tables until run-time.
Let me give another (once again, contrived) example, that might explain it a bit better.

Imagine that I have two sets of tables, one a set of transactional records (eg, sales records), and the other a set of consolidated tables for reporting. So I have a Sales table with attributes for Date/Time, ItemID & Price.

Then I have a set of tables that look like Sales201003, Sales201004, Sales201005, etc - a separate table for each year/month combination. (This is not the way I would design it - but this is how it is and so I need to deal with it).

The SalesYYYYMM tables have one row per day, per item, along with attributes for the total number sold, and total revenue.

So I have code that selects records from the Sales table, and then inserts summarised data into the appropriate SalesYYYYMM tables. The code I would _like_ to be able to write would look something like this:

# Some code here which selects data from Sales table # ... # ... # then... my @sales_inserts; my $insert_sql = 'INSERT INTO ? (ItemID, Day, Revenue, Count) VALUES ( +?, ?, ?, ?); my $sales_insert_dbq = $sales_dbh->prepare($insert_sql); while (my @data = $dbq->fetchrow_array) { my ($year, $month, $day, $itemid, $revenue, $count) = @data; my $sales_table = "Sales$year$month"; my @insert_values = ($sales_table, $day, $itemid, $revenue, $count +); push @sales_inserts, [@insert_values]; } eval { for my $i (0 .. $#sales_inserts) { $sales_insert_dbq->execute(@{$sales_inserts[$i]}); } $sales_dbh->commit; }; if ($@) { # Error handling, rollback, etc }
But the above won't work because I can't use a placeholder for a table name.
I can work around it easily enough by creating a separate statement handle for each YYYYMM combination.
I'm just not sure what the best approach to that would be.

Oh, and please ignore the fact that it's horrible data base design, and that calculated data is being written back into the data base. As I said, it's a contrived example that helps to describe my problem.

In reply to Re^2: DBI - Table names & placeholders by McDarren
in thread DBI - Table names & placeholders by McDarren

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

    What's my password?
    Create A New User
    and a log crumbles through the grate...

    How do I use this? | Other CB clients
    Other Users?
    Others romping around the Monastery: (3)
    As of 2018-01-24 04:51 GMT
    Find Nodes?
      Voting Booth?
      How did you see in the new year?

      Results (255 votes). Check out past polls.