Append data from one Hash Array to Another Hash Array...

[rkumar28]

Hi,

I have three functions as below. The two functions get_monthly_data() and get_daily_data() gets Monthly and Daily related data into their respective
Hash array(see the function below). Both the functions has same fields.
All I am trying to do is to merge(append the data from one hash to another hash). Put data from the two hash array of the two functions above into a third hash array.


#!/usr/bin/perl
$monthly_data = get_monthly_data();
$daily_data = get_daily_data();
$merge_data = get_merge_data( $monthly_data , $daily_data )

The $merge_data needs to have data from both $monthly_data , $daily_data

sub get_merge_data
{
How to append data from get_monthly_data() hash array and get_daily_data() hash array into a third Hashand return it from this function.
}



sub get_monthly_data
{
$dbh = DBI->connect("dbi:Oracle:$dbname", .....Database Connectivity......)
$cmd =
q { SELECT DISTINCT
ID, NAME, STATUS, SRC FROM TABLE A };

std = $dbh->prepare("$cmd");
$std->execute;
$hash_return = {};
$node_index=0;

while ( $hash_ref = $std->fetchrow_hashref )
{
push @{$hash_return->{$hash_ref->{'ID'}}}, $hash_ref;
$node_index++;
}
$std->finish;
$dbh->disconnect;
return($hash_return);
}

sub get_daily_data
{
$dbh = DBI->connect("dbi:Oracle:$dbname", .....Database Connectivity......)
$cmd =
q { SELECT DISTINCT
ID, NAME, STATUS, SRC FROM TABLE B };
std = $dbh->prepare("$cmd");
$std->execute;
$hash_return = {};
$node_index=0;
while ( $hash_ref = $std->fetchrow_hashref )
{
push @{$hash_return->{$hash_ref->{'ID'}}}, $hash_ref;
$node_index++;
}
$std->finish;
$dbh->disconnect;
return($hash_return);
}

 

[MillerH]

For those wishing to help rkumar28 out, I've run his code through perltidy:

#!/usr/bin/perl
$monthly_data = get_monthly_data();
$daily_data   = get_daily_data();
$merge_data   = get_merge_data( $monthly_data, $daily_data );

[b]# The $merge_data needs to have data from both $monthly_data , $daily_data [/b]

sub get_merge_data {

[b]# How to append data from get_monthly_data() hash array and get_daily_data() hash array into a third Hashand return it from this function.  [/b]
}

sub get_monthly_data {
    $dbh = DBI->connect( "dbi:Oracle:$dbname", .....Database Connectivity...... );
    $cmd = q{SELECT DISTINCT ID, NAME, STATUS, SRC FROM TABLE A};

    std = $dbh->prepare("$cmd");
    $std->execute;
    $hash_return = {};

    while ( $hash_ref = $std->fetchrow_hashref ) {
        push @{ $hash_return->{ $hash_ref->{'ID'} } }, $hash_ref;
    }
    $std->finish;
    $dbh->disconnect;
    return ($hash_return);
}

sub get_daily_data {
    $dbh = DBI->connect( "dbi:Oracle:$dbname", .....Database Connectivity...... );
    $cmd = q{SELECT DISTINCT ID, NAME, STATUS, SRC FROM TABLE B};
    
    std = $dbh->prepare("$cmd");
    $std->execute;
    $hash_return = {};
    
    while ( $hash_ref = $std->fetchrow_hashref ) {
        push @{ $hash_return->{ $hash_ref->{'ID'} } }, $hash_ref;
    }
    $std->finish;
    $dbh->disconnect;
    return ($hash_return);
}

 

[svar]

Ok, let's separate the tasks you have: You are running
a query and getting a datastructure
%{$hash_return}={key1=>[{reference to hash1},{%reference to hash2},....,{reference to hashN1}];

my guess is what you are trying to do with the second sql is
append to $hash_return->{$key1}, so that at the end of the day you want
%{$hash_return}={key1=>[{reference to hash1},{%reference to hash2},....,{reference to hashN1},{reference to secondhash1},{%reference to secondhash2},....,{reference to secondhashN2];


This would mean coding like this for the second sql fetch
(I assume here that at the end of the day everything will be stored in a single hash; if you want to save them separately, you can do that on the fly.
So I really do not see the need for two separate reads
and definitely not for a merge function; you can do everything on the fly)
...reading the second sql fetch
while ( $hash_ref = $std->fetchrow_hashref ) {
push @{ $hash_return->{ $hash_ref->{'ID'} } }, $hash_ref;
}

should do it. Just use the same hash_return reference for both monthly and daily
Of course I may have misunderstood the question....

 

[rkumar28]

Thanks Miller and Svar for replying. Thanks for the suggestion. Yes...I am trying to store eveything in single hash. I think what you are suggesting make sense and is more efficient. I will remove the merge statement.

Please correct me if I understood it correctly.I have to write both queries in a single function. Something like below (please see get_monthly_daily_data() function) .

I am not sure if I should post this separately as a new topic. My two sql queries are very long. Each are about two and half pages. I am planning to write these queries in two separate files test1.sql and test2.sql and call these files in my $cmd1 and $cmd2 below.... If possible...can you please suggest how to pass the sql from the two files into $cmd1 and $cmd2.



sub get_monthly_daily_data {
$dbh = DBI->connect( "dbi:Oracle:$dbname", .....Database Connectivity...... );

$hash_return = {};


$cmd1 = q{SELECT DISTINCT ID, NAME, STATUS, SRC FROM TABLE A};
std1 = $dbh->prepare("$cmd1");
$std1->execute;
while ( $hash_ref = $std1->fetchrow_hashref ) {
push @{ $hash_return->{ $hash_ref->{'ID'} } }, $hash_ref;
}
$std1->finish;
#### Query One finishes here ####



#### Query Two Starts here ####
$cmd2 = q{SELECT DISTINCT ID, NAME, STATUS, SRC FROM TABLE B};
std2 = $dbh->prepare("$cmd2");
$std2->execute;
while ( $hash_ref = $std2->fetchrow_hashref ) {
push @{ $hash_return->{ $hash_ref->{'ID'} } }, $hash_ref;
}
$std2->finish;


$dbh->disconnect;
return ($hash_return);
}