[LON-CAPA-cvs] cvs: loncom /metadata_database/LONCAPA lonmetadata.pm

[matthew]

matthew		Mon Jan 12 16:32:20 2004 EDT

  Modified files:              
    /loncom/metadata_database/LONCAPA	lonmetadata.pm 
  Log:
  Implement store_metadata.  lookup_metadata is not tested in the least.
  
  
Index: loncom/metadata_database/LONCAPA/lonmetadata.pm
diff -u loncom/metadata_database/LONCAPA/lonmetadata.pm:1.1 loncom/metadata_database/LONCAPA/lonmetadata.pm:1.2
--- loncom/metadata_database/LONCAPA/lonmetadata.pm:1.1	Mon Jan 12 10:07:08 2004
+++ loncom/metadata_database/LONCAPA/lonmetadata.pm	Mon Jan 12 16:32:20 2004
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonmetadata.pm,v 1.1 2004/01/12 15:07:08 matthew Exp $
+# $Id: lonmetadata.pm,v 1.2 2004/01/12 21:32:20 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -165,8 +165,8 @@
 
 Input: None
 
-Returns: An array of hash references describing the columns and rows
-of the metadata table.
+Returns: An array of hash references describing the columns and indicies
+of the metadata table(s).
 
 =cut
 
@@ -250,7 +250,63 @@
 
 ######################################################################
 ######################################################################
+{
+    ##
+    ##  WARNING: The following cleverness may cause trouble in cases where
+    ##  the dbi connection is dropped and recreated - a stale statement
+    ##  handler may linger around and cause trouble.
+    ##
+    ##  In most scripts, this will work fine.  If the dbi is going to be
+    ##  dropped and (possibly) later recreated, call &clear_sth.  Yes it
+    ##  is annoying but $sth appearantly does not have a link back to the 
+    ##  $dbh, so we can't check our validity.
+    ##
+    my $sth = undef;
+
+sub create_statement_handler {
+    my $dbh = shift();
+    my $request = 'INSERT INTO metadata VALUES(';
+    foreach (@Metadata_Table_Description) {
+        $request .= '?,';
+    }
+    chop $request;
+    $request.= ')';
+    $sth = $dbh->prepare($request);
+    return;
+}
+
+sub clear_sth { $sth=undef; }
+
 sub store_metadata {
+    my $dbh = shift();
+    my $errors = '';
+    if (! defined($sth)) {
+        &create_statement_handler($dbh);
+    }
+    my $successcount = 0;
+    while (my $mdata = shift()) {
+        next if (ref($mdata) ne "HASH");
+        my @MData;
+        foreach my $field (@Metadata_Table_Description) {
+            if (exists($mdata->{$field->{'name'}})) {
+                push(@MData,$mdata->{$field->{'name'}});
+            } else {
+                push(@MData,undef);
+            }
+        }
+        $sth->execute(@MData);
+        if (! $sth->err) {
+            $successcount++;
+        } else {
+            $errors = join(',',$errors,$sth->errstr);
+        }
+    }
+    if (wantarray()) {
+        return ($successcount,$errors);
+    } else {
+        return $successcount;
+    }
+}
 
 }
 
@@ -264,13 +320,38 @@
 Inputs: database handle ($dbh) and a hash or hash reference containing 
 metadata which will be used for a search.
 
-Returns: 
+Returns: scalar with error string on failure, array reference on success.
+The array reference is the same one returned by $sth->fetchall_arrayref().
 
 =cut
 
 ######################################################################
 ######################################################################
-sub lookup_metadata {}
+sub lookup_metadata {
+    my ($dbh,$condition,$fetchparameter) = @_;
+    my $error;
+    my $returnvalue=[];
+    my $request = 'SELECT * FROM metadata';
+    if (defined($condition)) {
+        $request .= ' WHERE '.$condition;
+    }
+    my $sth = $dbh->prepare($request);
+    if ($sth->err) {
+        $error = $sth->errstr;
+    }
+    if (! $error) {
+        $sth->execute();
+        if ($sth->err) {
+            $error = $sth->errstr;
+        } else {
+            $returnvalue = $sth->fetchall_arrayref($fetchparameter);
+            if ($sth->err) {
+                $error = $sth->errstr;
+            }
+        }
+    }
+    return ($error,$returnvalue);
+}
 
 ######################################################################
 ######################################################################