cust_bill_pay and cust_credit_refund.

payments can apply to multiple invoices and refunds can apply to multiple
credits.

7 files changed, 505 insertions, 39 deletions

diff --git a/FS/FS/cust_bill_pay.pm b/FS/FS/cust_bill_pay.pm
new file mode 100644
index 000000000..045a9490b
--- /dev/null
+++ b/FS/FS/cust_bill_pay.pm
@@ -0,0 +1,190 @@
+package cust_bill_pay;
+
+use strict;
+use vars qw( @ISA );
+use FS::Record qw( qsearch qsearchs dbh );
+#use FS::cust_bill
+
+@ISA = qw( FS::Record );
+
+=head1 NAME
+
+FS::cust_bill_pay - Object methods for cust_bill_pay records
+
+=head1 SYNOPSIS 
+
+  use FS::cust_bill_pay;
+
+  $record = new FS::cust_bill_pay \%hash;
+  $record = new FS::cust_bill_pay { 'column' => 'value' };
+
+  $error = $record->insert;
+
+  $error = $new_record->replace($old_record);
+
+  $error = $record->delete;
+
+  $error = $record->check;
+
+=head1 DESCRIPTION
+
+An FS::cust_bill_pay object represents the application of a payment to a
+specific invoice.  FS::cust_bill_pay inherits from FS::Record.  The following
+fields are currently supported:
+
+=over 4
+
+=item billpaynum - primary key (assigned automatically)
+
+=item invnum - Invoice (see L<FS::cust_bill>)
+
+=item paynum - Payment (see L<FS::cust_pay>)
+
+=item amount - Amount of the payment to apply to the specific invoice.
+
+=item _date - specified as a UNIX timestamp; see L<perlfunc/"time">.  Also see
+L<Time::Local> and L<Date::Parse> for conversion functions.
+
+=back
+
+=head1 METHODS
+
+=over 4 
+
+=item new HASHREF
+
+Creates a new record.  To add the record to the database, see L<"insert">.
+
+=cut
+
+sub table { 'cust_bill_pay'; }
+
+=item insert
+
+Adds this record to the database.  If there is an error, returns the error,
+otherwise returns false.
+
+=cut
+
+sub insert {
+  my $self = shift;
+
+  local $SIG{HUP} = 'IGNORE';
+  local $SIG{INT} = 'IGNORE';
+  local $SIG{QUIT} = 'IGNORE';
+  local $SIG{TERM} = 'IGNORE';
+  local $SIG{TSTP} = 'IGNORE';
+  local $SIG{PIPE} = 'IGNORE';
+
+  my $oldAutoCommit = $FS::UID::AutoCommit;
+  local $FS::UID::AutoCommit = 0;
+  my $dbh = dbh;
+
+  my $error = $self->check;
+  return $error if $error;
+
+  $error = $self->SUPER::insert;
+
+  my $cust_pay = qsearchs('cust_pay', { 'paynum' => $self->paynum } ) or do {
+    $dbh->rollback if $oldAutoCommit;
+    return "unknown cust_pay.paynum: ". $self->paynum;
+  };
+
+  my $pay_total = 0;
+  $pay_total += $_ foreach map { $_->amount }
+    qsearch('cust_bill_pay', { 'paynum' => $self->paynum } );
+
+  if ( $pay_total > $cust_pay->paid ) {
+    $dbh->rollback if $oldAutoCommit;
+    return "total cust_bill_pay.amount $pay_total for paynum ". $self->paynum.
+           " greater than cust_pay.paid ". $cust_pay->paid;
+  }
+
+  my $cust_bill = qsearchs('cust_bill', { 'invnum' => $self->invnum } ) or do {
+    $dbh->rollback if $oldAutoCommit;
+    return "unknown cust_bill.invnum: ". $self->invnum;
+  };
+
+  my $bill_total = 0;
+  $bill_total += foreach map { $_->amount }
+    qsearch('cust_bill_pay', { 'invnum' => $self->invnum } );
+#  $bill_total += foreach map { $_->amount } 
+#    qsearch('cust_credit_bill', { 'invnum' => $self->invnum } );
+  if ( $bill_total > $cust_bill->charged ) {
+    $dbh->rollback if $oldAutoCommit;
+    return "total cust_bill_pay.amount and cust_credit_bill.amount $bill_total".
+           "for invnum ". $self->invnum.
+           " greater than cust_bill.charged ". $cust_bill->charged;
+  }
+
+  $dbh->commit or die $dbh->errstr if $oldAutoCommit;
+
+  '';
+}
+
+=item delete
+
+Currently unimplemented (accounting reasons).
+
+=cut
+
+sub delete {
+  return "Can't (yet?) delete cust_bill_pay records!";
+}
+
+=item replace OLD_RECORD
+
+Currently unimplemented (accounting reasons).
+
+=cut
+
+sub replace {
+   return "Can't (yet?) modify cust_bill_pay records!";
+}
+
+=item check
+
+Checks all fields to make sure this is a valid payment.  If there is an error,
+returns the error, otherwise returns false.  Called by the insert method.
+
+=cut
+
+sub check {
+  my $self = shift;
+
+  my $error = 
+    $self->ut_numbern('billpaynum')
+    || $self->ut_number('invnum')
+    || $self->ut_numner('paynum')
+    || $self->ut_money('amount')
+    || $self->ut_numbern('_date')
+  ;
+  return $error if $error;
+
+  $self->_date(time) unless $self->_date;
+
+
+  ''; #no error
+}
+
+=back
+
+=head1 VERSION
+
+$Id: cust_bill_pay.pm,v 1.1 2001-09-01 20:11:07 ivan Exp $
+
+=head1 BUGS
+
+Delete and replace methods.
+
+cust_credit_bill isn't checked yet (uncomment around line 111)
+
+=head1 SEE ALSO
+
+L<FS::cust_pay>, L<FS::cust_bill>, L<FS::Record>, schema.html from the
+base documentation.
+
+=cut
+
+1;
+
diff --git a/FS/FS/cust_credit_refund.pm b/FS/FS/cust_credit_refund.pm
new file mode 100644
index 000000000..f366eb147
--- /dev/null
+++ b/FS/FS/cust_credit_refund.pm
@@ -0,0 +1,175 @@
+package cust_credit_refund;
+
+use strict;
+use vars qw( @ISA );
+use FS::Record qw( qsearch qsearchs dbh );
+#use FS::UID qw(getotaker);
+#use FS::cust_credit
+
+@ISA = qw( FS::Record );
+
+=head1 NAME
+
+FS::cust_credit_refund - Object methods for cust_bill_pay records
+
+=head1 SYNOPSIS 
+
+  use FS::cust_credit_refund;
+
+  $record = new FS::cust_credit_refund \%hash;
+  $record = new FS::cust_credit_refund { 'column' => 'value' };
+
+  $error = $record->insert;
+
+  $error = $new_record->replace($old_record);
+
+  $error = $record->delete;
+
+  $error = $record->check;
+
+=head1 DESCRIPTION
+
+An FS::cust_credit_refund represents the application of a refund to a specific
+credit.  FS::cust_credit_refund inherits from FS::Record.  The following fields
+are currently supported:
+
+=over 4
+
+=item creditrefundnum - primary key (assigned automatically)
+
+=item crednum - Credit (see L<FS::cust_credit>)
+
+=item refundnum - Refund (see L<FS::cust_refund>)
+
+=item amount - Amount of the refund to apply to the specific credit.
+
+=item _date - specified as a UNIX timestamp; see L<perlfunc/"time">.  Also see
+L<Time::Local> and L<Date::Parse> for conversion functions.
+
+=back
+
+=head1 METHODS
+
+=over 4 
+
+=item new HASHREF
+
+Creates a new record.  To add the record to the database, see L<"insert">.
+
+sub table { 'cust_credit_refund'; }
+
+=item insert
+
+Adds this record to the database.  If there is an error, returns the error,
+otherwise returns false.
+
+=cut
+
+sub insert {
+  my $self = shift;
+
+  local $SIG{HUP} = 'IGNORE';
+  local $SIG{INT} = 'IGNORE';
+  local $SIG{QUIT} = 'IGNORE';
+  local $SIG{TERM} = 'IGNORE';
+  local $SIG{TSTP} = 'IGNORE';
+  local $SIG{PIPE} = 'IGNORE';
+
+  my $oldAutoCommit = $FS::UID::AutoCommit;
+  local $FS::UID::AutoCommit = 0;
+  my $dbh = dbh;
+
+  my $error = $self->check;
+  return $error if $error;
+
+  $error = $self->SUPER::insert;
+
+  my $cust_refund =
+    qsearchs('cust_refund', { 'refundnum' => $self->refundnum } )
+  or do {
+    $dbh->rollback if $oldAutoCommit;
+    return "unknown cust_refund.refundnum: ". $self->refundnum
+  };
+
+  my $refund_total = 0;
+  $refund_total += $_ foreach map { $_->amount }
+    qsearch('cust_credit_refund', { 'refundnum' => $self->refundnum } );
+
+  if ( $refund_total > $cust_refund->refund ) {
+    $dbh->rollback if $oldAutoCommit;
+    return "total cust_credit_refund.amount $refund_total for refundnum ".
+           $self->refundnum.
+           " greater than cust_refund.refund ". $cust_refund->refund;
+  }
+
+  $dbh->commit or die $dbh->errstr if $oldAutoCommit;
+
+  '';
+}
+
+=item delete
+
+Currently unimplemented (accounting reasons).
+
+=cut
+
+sub delete {
+  return "Can't (yet?) delete cust_credit_refund records!";
+}
+
+=item replace OLD_RECORD
+
+Currently unimplemented (accounting reasons).
+
+=cut
+
+sub replace {
+   return "Can't (yet?) modify cust_credit_refund records!";
+}
+
+=item check
+
+Checks all fields to make sure this is a valid payment.  If there is an error,
+returns the error, otherwise returns false.  Called by the insert method.
+
+=cut
+
+sub check {
+  my $self = shift;
+
+  my $error = 
+    $self->ut_numbern('creditrefundnum')
+    || $self->ut_number('crednum')
+    || $self->ut_numner('refundnum')
+    || $self->ut_money('amount')
+    || $self->ut_numbern('_date')
+  ;
+  return $error if $error;
+
+  $self->_date(time) unless $self->_date;
+
+  return "unknown cust_credit.crednum: ". $self->crednum
+    unless qsearchs( 'cust_credit', { 'crednum' => $self->crednum } );
+
+  ''; #no error
+}
+
+=back
+
+=head1 VERSION
+
+$Id: cust_credit_refund.pm,v 1.1 2001-09-01 20:11:07 ivan Exp $
+
+=head1 BUGS
+
+Delete and replace methods.
+
+=head1 SEE ALSO
+
+L<FS::cust_credit>, L<FS::cust_refund>, L<FS::Record>, schema.html from the
+base documentation.
+
+=cut
+
+1;
+
diff --git a/FS/FS/cust_main.pm b/FS/FS/cust_main.pm
index 682b43d95..31f6d5e3e 100644
--- a/FS/FS/cust_main.pm
+++ b/FS/FS/cust_main.pm
@@ -1398,7 +1398,7 @@ sub rebuild_fuzzyfiles {
 
 =head1 VERSION
 
-$Id: cust_main.pm,v 1.22 2001-08-28 14:34:14 ivan Exp $
+$Id: cust_main.pm,v 1.23 2001-09-01 20:11:07 ivan Exp $
 
 =head1 BUGS
 
@@ -1415,8 +1415,6 @@ CyberCash v2 forces us to define some variables in package main.
 There should probably be a configuration file with a list of allowed credit
 card types.
 
-CyberCash is the only processor.
-
 No multiple currency support (probably a larger project than just this module).
 
 =head1 SEE ALSO
diff --git a/FS/FS/cust_pay.pm b/FS/FS/cust_pay.pm
index f0d945060..b1c35d76f 100644
--- a/FS/FS/cust_pay.pm
+++ b/FS/FS/cust_pay.pm
@@ -3,8 +3,9 @@ package FS::cust_pay;
 use strict;
 use vars qw( @ISA );
 use Business::CreditCard;
-use FS::Record qw( qsearchs );
+use FS::Record qw( dbh );
 use FS::cust_bill;
+use FS::cust_bill_pay;
 
 @ISA = qw( FS::Record );
 
@@ -37,8 +38,6 @@ currently supported:
 
 =item paynum - primary key (assigned automatically for new payments)
 
-=item invnum - Invoice (see L<FS::cust_bill>)
-
 =item paid - Amount of this payment
 
 =item _date - specified as a UNIX timestamp; see L<perlfunc/"time">.  Also see
@@ -66,21 +65,55 @@ sub table { 'cust_pay'; }
 
 =item insert
 
-Adds this payment to the databse, and updates the invoice (see
-L<FS::cust_bill>).
+Adds this payment to the database.
+
+For backwards-compatibility and convenience, if the additional field invnum
+is defined, an FS::cust_bill_pay record for the full amount of the payment
+will be created.
 
 =cut
 
 sub insert {
   my $self = shift;
 
+  local $SIG{HUP} = 'IGNORE';
+  local $SIG{INT} = 'IGNORE';
+  local $SIG{QUIT} = 'IGNORE';
+  local $SIG{TERM} = 'IGNORE';
+  local $SIG{TSTP} = 'IGNORE';
+  local $SIG{PIPE} = 'IGNORE';
+
+  my $oldAutoCommit = $FS::UID::AutoCommit;
+  local $FS::UID::AutoCommit = 0;
+  my $dbh = dbh;
+
   my $error = $self->check;
   return $error if $error;
 
-  my $old_cust_bill = qsearchs( 'cust_bill', { 'invnum' => $self->invnum } );
-  return "Unknown invnum" unless $old_cust_bill;
+  $error = $self->SUPER::insert;
+  if ( $error ) {
+    $dbh->rollback if $oldAutoCommit;
+    return $error;
+  }
+
+  if ( $self->invnum ) {
+    my $cust_bill_pay = new FS::cust_bill_pay {
+      'invnum' => $self->invnum,
+      'paynum' => $self->paynum,
+      'amount' => $self->paid,
+      '_date'  => $self->_date,
+    };
+    $error = $cust_bill_pay->insert;
+    if ( $error ) {
+      $dbh->rollback if $oldAutoCommit;
+      return $error;
+    }
+  }
+
+  $dbh->commit or die $dbh->errstr if $oldAutoCommit;
+
+  '';
 
-  $self->SUPER::insert;
 }
 
 =item delete
@@ -113,13 +146,11 @@ returns the error, otherwise returns false.  Called by the insert method.
 sub check {
   my $self = shift;
 
-  my $error;
-
-  $error =
+  my $error =
     $self->ut_numbern('paynum')
-    || $self->ut_number('invnum')
     || $self->ut_money('paid')
     || $self->ut_numbern('_date')
+    || $self->ut_textn('paybatch')
   ;
   return $error if $error;
 
@@ -147,9 +178,6 @@ sub check {
     return $error if $error;
   }
 
-  $error = $self->ut_textn('paybatch');
-  return $error if $error;
-
   ''; #no error
 
 }
@@ -158,7 +186,7 @@ sub check {
 
 =head1 VERSION
 
-$Id: cust_pay.pm,v 1.3 2001-04-09 23:05:15 ivan Exp $
+$Id: cust_pay.pm,v 1.4 2001-09-01 20:11:07 ivan Exp $
 
 =head1 BUGS
 
@@ -166,7 +194,8 @@ Delete and replace methods.
 
 =head1 SEE ALSO
 
-L<FS::Record>, L<FS::cust_bill>, schema.html from the base documentation.
+L<FS::cust_bill_pay>, L<FS::cust_bill>, L<FS::Record>, schema.html from the
+base documentation.
 
 =cut
 
diff --git a/FS/FS/cust_refund.pm b/FS/FS/cust_refund.pm
index 729dc02b0..8e4ef0d4e 100644
--- a/FS/FS/cust_refund.pm
+++ b/FS/FS/cust_refund.pm
@@ -3,9 +3,10 @@ package FS::cust_refund;
 use strict;
 use vars qw( @ISA );
 use Business::CreditCard;
-use FS::Record qw( qsearchs );
+use FS::Record qw( qsearchs dbh );
 use FS::UID qw(getotaker);
 use FS::cust_credit;
+use FS::cust_credit_refund;
 
 @ISA = qw( FS::Record );
 
@@ -38,8 +39,6 @@ inherits from FS::Record.  The following fields are currently supported:
 
 =item refundnum - primary key (assigned automatically for new refunds)
 
-=item crednum - Credit (see L<FS::cust_credit>)
-
 =item refund - Amount of the refund
 
 =item _date - specified as a UNIX timestamp; see L<perlfunc/"time">.  Also see
@@ -49,6 +48,8 @@ L<Time::Local> and L<Date::Parse> for conversion functions.
 
 =item payinfo - card number, P.O.#, or comp issuer (4-8 lowercase alphanumerics; think username)
 
+=item paybatch - text field for tracking card processing
+
 =item otaker - order taker (assigned automatically, see L<FS::UID>)
 
 =back
@@ -67,22 +68,55 @@ sub table { 'cust_refund'; }
 
 =item insert
 
-Adds this refund to the database, and updates the credit (see
-L<FS::cust_credit>).
+Adds this refund to the database.
+
+For backwards-compatibility and convenience, if the additional field crednum is
+defined, an FS::cust_credit_refund record for the full amount of the refund
+will be created.
 
 =cut
 
 sub insert {
   my $self = shift;
 
+  local $SIG{HUP} = 'IGNORE';
+  local $SIG{INT} = 'IGNORE';
+  local $SIG{QUIT} = 'IGNORE';
+  local $SIG{TERM} = 'IGNORE';
+  local $SIG{TSTP} = 'IGNORE';
+  local $SIG{PIPE} = 'IGNORE';
+
+  my $oldAutoCommit = $FS::UID::AutoCommit;
+  local $FS::UID::AutoCommit = 0;
+  my $dbh = dbh;
+
   my $error = $self->check;
   return $error if $error;
 
-  my $old_cust_credit =
-    qsearchs( 'cust_credit', { 'crednum' => $self->crednum } );
-  return "Unknown crednum" unless $old_cust_credit;
+  $error = $self->SUPER::insert;
+  if ( $error ) {
+    $dbh->rollback if $oldAutoCommit;
+    return $error;
+  }
+
+  if ( $self->crednum ) {
+    my $cust_credit_refund = new FS::cust_credit_refund {
+      'cred' => $self->cred,
+      'refundnum' => $self->refundnum,
+      'amount' => $self->refund,
+      '_date' => $self->_date,
+    };
+    $error = $cust_bill_pay->insert;
+    if ( $error ) {
+      $dbh->rollback if $oldAutoCommit;
+      return $error;
+    }
+  }
+
+  $dbh->commit or die $dbh->errstr if $oldAutoCommit;
+
+  '';
 
-  $self->SUPER::insert;
 }
 
 =item delete
@@ -115,13 +149,11 @@ returns the error, otherwise returns false.  Called by the insert method.
 sub check {
   my $self = shift;
 
-  my $error;
-
-  $error =
+  my $error =
     $self->ut_number('refundnum')
-    || $self->ut_number('crednum')
     || $self->ut_money('amount')
     || $self->ut_numbern('_date')
+    || $self->ut_textn('paybatch')
   ;
   return $error if $error;
 
@@ -157,7 +189,7 @@ sub check {
 
 =head1 VERSION
 
-$Id: cust_refund.pm,v 1.3 2001-04-09 23:05:15 ivan Exp $
+$Id: cust_refund.pm,v 1.4 2001-09-01 20:11:07 ivan Exp $
 
 =head1 BUGS
 
diff --git a/bin/fs-setup b/bin/fs-setup
index faa0e07f1..2cba840ef 100755
--- a/bin/fs-setup
+++ b/bin/fs-setup
@@ -1,6 +1,6 @@
 #!/usr/bin/perl -Tw
 #
-# $Id: fs-setup,v 1.44 2001-08-29 08:45:04 ivan Exp $
+# $Id: fs-setup,v 1.45 2001-09-01 20:11:07 ivan Exp $
 
 #to delay loading dbdef until we're ready
 BEGIN { $FS::Record::setup_hack = 1; }
@@ -398,7 +398,7 @@ sub tables_hash_hack {
     'cust_pay' => {
       'columns' => [
         'paynum',   'int',    '',   '',
-        'invnum',   'int',    '',   '',
+        #now cust_bill_pay #'invnum',   'int',    '',   '',
         'paid',     @money_type,
         '_date',    @date_type,
         'payby',    'char',   '',     4, # CARD/BILL/COMP, should be index into
@@ -411,6 +411,19 @@ sub tables_hash_hack {
       'index' => [ ['invnum'] ],
     },
 
+    'cust_bill_pay' => {
+      'column' => [
+        'billpaynum', 'int',     '',   '',
+        'invnum',  'int',     '',   '',
+        'paynum',  'int',     '',   '',
+        'amount',  @money_type,
+        '_date',   @date_type
+      ],
+      'primary_key' => 'billpaynum'
+      'unique' => [ [] ],
+      'index' => [ [ 'paynum', 'invnum' ] ],
+    },
+
     'cust_pay_batch' => { #what's this used for again?  list of customers
                           #in current CARD batch? (necessarily CARD?)
       'columns' => [
@@ -456,7 +469,7 @@ sub tables_hash_hack {
     'cust_refund' => {
       'columns' => [
         'refundnum',    'int',    '',   '',
-        'crednum',      'int',    '',   '',
+        #now cust_credit_refund #'crednum',      'int',    '',   '',
         '_date',        @date_type,
         'refund',       @money_type,
         'otaker',       'varchar',   '',   8,
@@ -464,12 +477,27 @@ sub tables_hash_hack {
         'payby',        'char',   '',     4, # CARD/BILL/COMP, should be index
                                              # into payment type table.
         'payinfo',      'varchar',   'NULL', 16,  #see cust_main above
+        'paybatch',     'varchar',   'NULL', $char_d,
       ],
       'primary_key' => 'refundnum',
       'unique' => [ [] ],
       'index' => [ ['crednum'] ],
     },
 
+    'cust_credit_refund' => {
+      'column' => [
+        'creditrefundnum', 'int',     '',   '',
+        'crednum',  'int',     '',   '',
+        'refundnum',  'int',     '',   '',
+        'amount',  @money_type,
+        '_date',   @date_type
+      ],
+      'primary_key' => 'creditrefundnum'
+      'unique' => [ [] ],
+      'index' => [ [ 'crednum', 'refundnum' ] ],
+    },
+
+
     'cust_svc' => {
       'columns' => [
         'svcnum',    'int',    '',   '',
diff --git a/httemplate/docs/schema.html b/httemplate/docs/schema.html
index 0da33a5c2..818547e1c 100644
--- a/httemplate/docs/schema.html
+++ b/httemplate/docs/schema.html
@@ -100,13 +100,20 @@
     <li><a name="cust_pay" href="man/FS/cust_pay.html">cust_pay</a> - Payments.  Money being transferred from a customer.
       <ul>
         <li>paynum - primary key
-        <li>invnum - <a href="#cust_bill">invoice</a>
         <li>paid - amount
         <li>_date
         <li>payby - CARD, BILL, or COMP
         <li>payinfo - card number, P.O.#, or comp issuer
         <li>paybatch - text field for tracking card processor batches
       </ul>
+    <li><a name="cust_bill_pay" href="man/FS/cust_bill_pay.html">cust_bill_pay</a> - Applicaton of a payment to a specific invoice.
+      <ul>
+        <li>billpaynum
+        <li>invnum - <a href="#cust_bill">invoice</a>
+        <li>paynum - <a href="#cust_pay">payment</a>
+        <li>amount
+        <li>_date
+      </ul>
     <li><a name="cust_pay_batch" href="man/FS/cust_pay_batch.html">cust_pay_batch</a> - Pending batch
       <ul>
         <li>trancode - 77 for charges
@@ -140,13 +147,20 @@
     <li><a name="cust_refund" href="man/FS/cust_refund.html">cust_refund</a> - Refunds.  The transfer of money to a customer; equivalent to a negative <a href="#cust_pay">cust_pay</a> record.
       <ul>
         <li>refundnum - primary key
-        <li>crednum - <a href="#cust_credit">credit</a>
         <li>refund - amount
         <li>_date
         <li>payby - CARD, BILL or COMP
         <li>payinfo - card number, P.O.#, or comp issuer
         <li>otaker - order taker
       </ul>
+    <li><a name="cust_credit_refund" href="man/FS/cust_credit_refund.html">cust_credit_refund</a> - Applicaton of a refund to a specific credit.
+      <ul>
+        <li>creditrefundnum - primary key
+        <li>crednum - <a href="#cust_credit">credit</a>
+        <li>refundnum - <a href="#cust_refund">refund</a>
+        <li>amount
+        <li>_date
+      </ul>
     <li><a name="cust_svc" href="man/FS/cust_svc.html">cust_svc</a> - Customer services
       <ul>
         <li>svcnum - primary key