add convenience method

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/sqlclient/trunk@28691 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,10 @@
+2009-09-16 Richard Frith-Macdonald  <rfm@gnu.org>
+
+	* SQLClient.h:
+	* SQLClient.m:
+	Add convenience method to convert array of rows into an array of
+	columns.
+
 2009-09-08 Richard Frith-Macdonald  <rfm@gnu.org>
 
 	* SQLClient.h:

SQLClient.h

@@ -1046,6 +1046,13 @@ extern unsigned	SQLClientTimeTick();
  */
 - (SQLTransaction*) batch: (BOOL)stopOnFailure;
 
+/**
+ * Convenience method to deal with the results of a query converting the
+ * normal array of records into an array of record columns.  Each column
+ * in the array is an array containing all the values from that column.
+ */
+- (NSMutableArray*) columns: (NSMutableArray*)records;
+
 /**
  * Executes a query (like the -query:,... method) and checks the result
  * (raising an exception if the query did not contain a single record)

SQLClient.m

@@ -2150,6 +2150,7 @@ static unsigned int	maxConnections = 8;
     }
   NS_HANDLER
     {
+      result = nil;
       [lock unlock];
       [localException raise];
     }
@@ -2460,6 +2461,43 @@ static unsigned int	maxConnections = 8;
   return AUTORELEASE((SQLTransaction*)transaction);
 }
 
+- (NSMutableArray*) columns: (NSMutableArray*)records
+{
+  SQLRecord		*r = [records lastObject];
+  unsigned		rowCount = [records count];
+  unsigned		colCount = [r count];
+  NSMutableArray	*m;
+
+  if (rowCount == 0 || colCount == 0)
+    {
+      m = [NSMutableArray array];
+    }
+  else
+    {
+      NSMutableArray	*cols[colCount];
+      unsigned		i;
+
+      m = [NSMutableArray arrayWithCapacity: colCount];
+      for (i = 0; i < colCount; i++)
+	{
+	  cols[i] = [[NSMutableArray alloc] initWithCapacity: rowCount];
+	  [m addObject: cols[i]];
+	  [cols[i] release];
+	}
+      for (i = 0; i < rowCount; i++)
+	{
+	  unsigned	j;
+
+	  r = [records objectAtIndex: i];
+	  for (j = 0; j < colCount; j++)
+	    {
+	      [cols[j] addObject: [r objectAtIndex: j]];
+	    }
+	}
+    }
+  return m;
+}
+
 - (SQLRecord*) queryRecord: (NSString*)stmt, ...
 {
   va_list	ap;