Connector/ODBC 5 commit: r545 - trunk/SDK/MYSQLPlus/Library

[pharvey]

Modified:
   trunk/SDK/MYSQLPlus/Library/MResult.h
   trunk/SDK/MYSQLPlus/Library/MResultRes.cpp
Log:
- changes/additions for block-cursor support


Modified: trunk/SDK/MYSQLPlus/Library/MResult.h
===================================================================
--- trunk/SDK/MYSQLPlus/Library/MResult.h	2006-09-14 19:33:25 UTC (rev 544)
+++ trunk/SDK/MYSQLPlus/Library/MResult.h	2006-09-15 18:25:55 UTC (rev 545)
@@ -188,20 +188,21 @@
                 (1st choice)
                 -------------------
 
-                    We do not buffer ResultSet.  This is our preferred use case because
it is most efficient. 
+                    We do not buffer ResultSet.  This is our preferred use-case because
it is most efficient. 
 
                     Pros;
                         - does not have to pull all data to client during doExecute()
                         - uses less storage on client
 
                     Cons;
-                        - cursor can only move forward (sequentially)
-                        - we do not know ResultSetRows
+                        - cursor can only move forward (sequentially - as in doNext)
+                        - we do not know ResultSetRows (so ResultSetRows is always
approx. and <= real ResultSetRows)
                      
                     Used if; 
                         - CURSOR_TYPE_FORWARD_ONLY
 
-                    We can still update a fully unbuffered ResultSet because we always
buffer a RowSet.
+                    We can still update a fully unbuffered ResultSet because we always
buffer a RowSet. This does, however,
+                    limit our options for cursor sensitivity.
 
                 BUFFERED_MYSQL_CLIENT 
                 (2nd choice)
@@ -216,7 +217,7 @@
                     Cons;
                         - pulls all data to client during doExecute()
                         - can cause considerable storage to be used on client
-                        - the ResultSet is read-only
+                        - the ResultSet is read-only (as we do not want to sync our
changes server<->client)
 
                     Used if;
                         - CONCURRENCY_READ_ONLY
@@ -226,22 +227,22 @@
                 -------------------
 
                     We buffer ResultSet in MResult. Buffer is built up, as used, from a
forward-only cursor in mysql client or is 
-                    otherwise created in MResult. 
+                    otherwise created in MResult (\sa MResultPlus). 
 
                     Pros;
                         - the cursor can be moved randomly about the ResultSet
-                        - we know ResultSetRows
-                        - ResultSetRows is deferred which deferrs pulling all data to
client
+                        - ResultSetRows is deferred which defers pulling all data to
client - possibly add option to get ResultSetRows 
+                          at doExecute enable this by switching 'use' result with 'store'
result - but this means even more double buffering
 
                     Cons;
                         - can cause considerable storage to be used on client
                         - more shuffling of data may be involved                
 
                     Used if;
-                        - not CURSOR_TYPE_FORWARD_ONLY and not CONCURRENCY_READ_ONLY
+                        - not CURSOR_TYPE_FORWARD_ONLY and not CONCURRENCY_READ_ONLY 
 
-                    MYSQLPlus will buffer keys when CURSOR_TYPE_KEYSET_DRIVEN or
CURSOR_TYPE_DYNAMIC. We do not really
-                    support CURSOR_TYPE_DYNAMIC - we just do same thing as
CURSOR_TYPE_KEYSET_DRIVEN.
+                    MYSQLPlus implements CURSOR_TYPE_KEYSET_DRIVEN with the use of
additional buffers which operate in parallel with data 
+                    buffers. We do not really support CURSOR_TYPE_DYNAMIC - we just do
same thing as CURSOR_TYPE_KEYSET_DRIVEN.
     */
     enum BUFFERED
     {

Modified: trunk/SDK/MYSQLPlus/Library/MResultRes.cpp
===================================================================
--- trunk/SDK/MYSQLPlus/Library/MResultRes.cpp	2006-09-14 19:33:25 UTC (rev 544)
+++ trunk/SDK/MYSQLPlus/Library/MResultRes.cpp	2006-09-15 18:25:55 UTC (rev 545)
@@ -432,11 +432,9 @@
 
         case BUFFERED_MYSQL_PLUS:
             // have we buffered everything yet?
-            if ( !isResultSetRowsKnown() )
+            while ( !isResultSetRowsKnown() && nRow + getRowSetSize() >
getResultSetRows() )
             {
-                // do we need to load more data into our buffered ResultSet?
-                if ( getResultSetRows() < getRowSetSize() )
-                    nReturn1 = getRowSetData();
+                nReturn1 = getRowSetData();
             }
             break;