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2007-10-31 #2

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Operating on Postgresql databases in perl

See:

http://structbio.vanderbilt.edu/chazin/wisdom/dbi_howto.html

To execute a basic SQL statement:

There are three steps to executing a basic SQL statement:

Prepare the statement:

This example is a statement that will retrieve the rows in a table called reference.

$sth = $dbh->prepare( "
SELECT reference.ref_num, type, reference.title, pub_year, summary
FROM reference
");
if ( !defined $sth ) {
die "Cannot prepare statement: $DBI::errstrn";
}

Execute the statement:

This is done using the following line:

$sth->execute;

Fetch the rows into an array or variables:

This is an example that fetches the attributes from the rows into variables:

while ( ($ref_num, $type, $title, $pub_year, $summary ) = $sth->fetchrow()){
...intervening code…
}

This is an example that fetches the attributes into an array:

while ( @row = $sth->fetchrow()){
...intervening code…
}

After you are finished with the SQL statement, you should release the statement handle as follows:

$sth->finish;

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2007-10-31 #2

Operating on Postgresql databases in perl

To execute a basic SQL statement:

Virtual Dave Megaplex:

Useful: