在Perl中执行SQL文件

Question

We have a Perl script which runs a SQL and puts data in the table. Now instead of supplying a single SQL statement, we want to pass bunch of them putting them together in a .sql file. We know that our program will fail because it expects a single SQL statement, not s bunch of them (that too from a .sql file). How do we make it work with a .sql file (having multiple INSERT statements?). We are using the DBI package.

A small snippet of code:

$sth = $dbh->prepare("/home/user1/tools/mytest.sql");
$sth->execute || warn "Couldn't execute statement";
$sth->finish();

Answer 1

There is a sort of workaround for DDL. You need to slurp SQL file first and then enclose it's contents into BEGIN ... END; keywords. Like:

sub exec_sql_file {
    my ($dbh, $file) = @_;

    my $sql = do {
        open my $fh, '<', $file or die "Can't open $file: $!";
        local $/;
        <$fh>
    };

    $dbh->do("BEGIN $sql END;");
}

This subroutine allows to run DDL (SQL) scripts with multiple statements inside (eg database dumps).

Answer 2

You don't need perl for this at all. Just use the mysql command line client:

mysql -h [hostname] -u[username] -p[password] [database name] < /home/user1/tools/mytest.sql

replace the [variables] with your information.

Note no space after -u or -p. If your mysql server is running on the same machine you can omit -h[hostname] (it defaults to localhost)

Answer 3

Not exactly sure what you want...

Once you create a DBI object, you can use it over and over again. Here I'm reading SQL statement after SQL statement from a file and processing each and every one in order:

use DBI;

my $sqlFile = "/home/user1/tools/mytest.sql"

my $dbh = DBI::Connect->new($connect, $user, $password)
    or die("Can't access db");

# Open the file that contains the various SQL statements
# Assuming one SQL statement per line

open (SQL, "$sqlFile")
    or die("Can't open file $sqlFile for reading");

# Loop though the SQL file and execute each and every one.
while (my $sqlStatement = <SQL>) {
   $sth = dbi->prepare($sqlStatement)
      or die("Can't prepare $sqlStatement");

   $sth->execute()
      or die("Can't execute $sqlStatement");
}

Notice that I'm putting the SQL statement in the prepare and not the file name that contains the SQL statement. Could that be your problem?

Answer 4

Here is how I've done it. In my case I dont assume one SQL per line and I assume, my example is a bit better :)

sub get_sql_from_file {
    open my $fh, '<', shift or die "Can't open SQL File for reading: $!";
    local $/;
    return <$fh>;
};

my $SQL = get_sql_from_file("SQL/file_which_holds_sql_statements.sql");
my $sth1 = $dbh1->prepare($SQL);
$sth1->execute();