#!/usr/local/bin/perl 

use UnixODBC qw(:all);
use Getopt::Long;

my $env;
my $cnh;
my $sth;
my $r;

## 
## Connection parameters from command line.
##
my $DSN;       # Data source name.
my $UserName;  # User login to DBMS
my $PassWord;  # Password login to DBMS
my $Table;     # Name of table.

my $usage=<<EOH;
Usage: 
apifuncs --help 
apifuncs --dsn=DSN --table=tablename --user=username --password=password [--brief] [--fieldsep]
  --help       Print this help and exit.
  --dsn        Data source name.
  --table      Table name.
  --user       DBMS login name.
  --password   DBMS login password.
  --brief      Print attributes without label headings.
  --fieldsep   Field separator.  Default is a tab character (0x09).
EOH

my $help;  # Print help and exit.
my $brief; # Do not print attribute labels.
my $fieldsep = "\t";  # Default field separator.

GetOptions ('help' => \$help,
	    'brief' => \$brief,
	    'fieldsep=s' => \$fieldsep,
	    'dsn=s' => \$DSN,
	    'user=s' => \$UserName,
            'table=s' => \$Table,
	    'password=s' => \$PassWord);

if ($help || (not length ($DSN)) || (not length ($UserName)) 
    || (not length ($Table)) || (not length ($UserName)) || 
    (not length ($PassWord)))
     {
	 print $usage;
	 exit 0;
}

my ($rbuf, $rbuflen, $numeric_attr, $ncols);

my @headings = qw(SQL_COLUMN_COUNT SQL_COLUMN_NAME SQL_COLUMN_TYPE
		  SQL_COLUMN_LENGTH SQL_COLUMN_PRECISION 
		  SQL_COLUMN_SCALE SQL_COLUMN_DISPLAY_SIZE
		  SQL_COLUMN_NULLABLE SQL_COLUMN_UNSIGNED
		  SQL_COLUMN_MONEY SQL_COLUMN_UPDATABLE
		  SQL_COLUMN_AUTO_INCREMENT SQL_COLUMN_CASE_SENSITIVE
		  SQL_COLUMN_SEARCHABLE SQL_COLUMN_TYPE_NAME
		  SQL_COLUMN_TABLE_NAME SQL_COLUMN_OWNER_NAME
		  SQL_COLUMN_QUALIFIER_NAME SQL_COLUMN_LABEL
		  SQL_COLUMN_DRIVER_START);

my @rowbuffer;  # Buffer attributes in correct order before printing.

my $query = "select \* from $Table\;";

my %numeric_attrs = ('SQL_COLUMN_COUNT', 0,
		     'SQL_COLUMN_TYPE', 2,
		     'SQL_COLUMN_LENGTH', 3,
		     'SQL_COLUMN_PRECISION', 4,
		     'SQL_COLUMN_SCALE', 5,
		     'SQL_COLUMN_DISPLAY_SIZE', 6,
		     'SQL_COLUMN_NULLABLE', 7,
		     'SQL_COLUMN_UNSIGNED', 8,
		     'SQL_COLUMN_MONEY', 9,
		     'SQL_COLUMN_UPDATABLE', 10,
		     'SQL_COLUMN_AUTO_INCREMENT', 11,
		     'SQL_COLUMN_CASE_SENSITIVE', 12,
		     'SQL_COLUMN_SEARCHABLE', 13,
		     'SQL_COLUMN_DRIVER_START', 1000,
		     );

my %char_attrs = ('SQL_COLUMN_NAME', 1,
		'SQL_COLUMN_TYPE_NAME', 14,
		'SQL_COLUMN_TABLE_NAME', 15,
		'SQL_COLUMN_OWNER_NAME', 16,
		'SQL_COLUMN_QUALIFIER_NAME', 17,
		'SQL_COLUMN_LABEL', 18,
		 );

$r = SQLAllocHandle ($SQL_HANDLE_ENV, $SQL_NULL_HANDLE, $evh);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    print "SQLAllocHandle evh: ";
   &getdiagrec ($SQL_HANDLE_ENV, $evh);
    exit 1;
}

$r = SQLSetEnvAttr($evh, $SQL_ATTR_ODBC_VERSION, $SQL_OV_ODBC2, 0);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_ENV, $evh);
    exit 1;
}

$r = SQLAllocHandle ($SQL_HANDLE_DBC, $evh, $cnh);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_ENV, $evh);
    exit 1;
}

$r = SQLConnect ($cnh, $DSN, $SQL_NTS,
			    $UserName, $SQL_NTS,
			    $PassWord, $SQL_NTS);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_DBC, $cnh);
    exit 1;
}

$r = SQLAllocHandle ($SQL_HANDLE_STMT, $cnh, $sth);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_DBC, $cnh);
    exit 1;
}

$r = &UnixODBC::SQLPrepare ($sth, $query, length ($query));
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_STMT, $sth);
    exit 1;
}

$r = &UnixODBC::SQLExecute ($sth);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_STMT, $sth);
    exit 1;
}


# Get the number of columns in the table
$r = &UnixODBC::SQLNumResultCols ($sth,$ncols);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_STMT, $sth);
    exit 1;
}

if (not $brief) { # Print column count and attribute headings.
    print "$ncols columns in $Table.\n";
    for (my $i = 0; $i <= $#headings; $i++) {
	print $headings[$i] . $fieldsep;
    }
    print "\n";
}

for (my $cn = 1; $cn <= $ncols; $cn++) {
    for (my $i = 0; $i <= $#headings; $i++) {
	foreach my $attr (keys %char_attrs) {
	    $r = SQLColAttribute ($sth, $cn, $char_attrs{$attr},
				  $rbuf, 255, $rbuflen, $numeric_attr);
	    for (my $j = 0; $j <= $#headings; $j++) {
		if ($attr =~ m"$headings[$j]") {
		    $rowbuffer[$j] = $rbuf;
		}
	    }
	}
	foreach  my $attr (keys %numeric_attrs) {
	    $r = SQLColAttribute ($sth, $cn, $numeric_attrs{$attr},
				  $rbuf, 255, $rbuflen, $numeric_attr);
	    for (my $j = 0; $j <= $#headings; $j++) {
		if ($attr =~ m"$headings[$j]") {
		    $rowbuffer[$j] = $numeric_attr;
		}
	    }
	}
    }
    foreach my $f (@rowbuffer) {
	print $f . $fieldsep;
    }
    print "\n";
}

if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_STMT, $sth);
    exit 1;
}

$r = SQLFreeHandle ($SQL_HANDLE_STMT, $sth);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_STMT, $sth);
    exit 1;
}

$r = SQLDisconnect ($cnh);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_DBC, $cnh);
    exit 1;
}

$r = SQLFreeConnect ($cnh);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_DBC, $cnh);
    exit 1;
}

$r = SQLFreeHandle ($SQL_HANDLE_ENV, $evh);
if (($r!=$SQL_SUCCESS)&&($r!=$SQL_NO_DATA)) {
    &getdiagrec ($SQL_HANDLE_ENV, $evh);
    exit 1;
}

sub getdiagrec {
    my ($handle_type, $handle) = @_;
    my ($sqlstate, $native, $message_text, $mlen);
    print 'SQLGetDiagRec: ';
    $r = &UnixODBC::SQLGetDiagRec ($handle_type, $handle, 1, $sqlstate,
				   $native, $message_text, 255,
				   $mlen);
    if ($r == $SQL_NO_DATA) { 
	print "result \= SQL_NO_DATA\n";
    } elsif (($r == 1) || ($r == 0)) { 
     print "$message_text\n";
    } else { 
     print "sqlresult = $r\n";
    }
    return $r;
}
