Re: Problem with DBI and placeholders

On 4/9/21 7:11 AM, mailing lists via beginners wrote:
> thanks Andrew
> 
> I need to insert millions of rows so I need to have a good performance 
> using placeholders
> 
> 

You can not use placeholders for the table name.

If you have millions of *tables*, there is something very, very, very 
wrong with your database design.

"Premature optimization is the root of all evil" -- do you have hard 
numeric evidence that the time to create the statement-handle is the 
bottleneck in your system, or are you leaping to the conclusion that you 
"need" to parameterize the table name?

If you have only a few dozen tables, and you need the same statement for 
all of them, then something like

my %sth_for_table;
for my $table qw / foo bar baz waldo pepper salt pork … chains/ {
   $sth_for_table{$table} = $dbh->prepare("whatever whatever into $table");

}

then use the appropriate $sth from the hash for your execute.

That said:  Needing to parameterize the *table name* is an absolute sure 
sign that "You're doing it wrong"


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