check for errors with multiple multi-query batches

[jpuck]

When using the surrogate key generator and inserting batches, if a query fails in the batch, then errors are silently ignored.

[jpuck]

I think the best that can happen for this is implemented with 62062b6 because there seems to be an unresolved bug with PDO_ODBC that fails to get errors with subsequent multi-queries on the same connection.

Even trying to clear the connection by setting the PDO instance to NULL doesn't work probably because a cached connection is used.

If you're using the PDO ODBC driver and your ODBC libraries support ODBC Connection Pooling (unixODBC and Windows are two that do; there may be more), then it's recommended that you don't use persistent PDO connections, and instead leave the connection caching to the ODBC Connection Pooling layer. The ODBC Connection Pool is shared with other modules in the process; if PDO is told to cache the connection, then that connection would never be returned to the ODBC connection pool, resulting in additional connections being created to service those other modules.

However, it might be possible to override the default behavior in php.ini by setting pdo_odbc.connection_pooling to "off"

Whether to pool ODBC connections. Can be one of "strict", "relaxed" or "off" (equals to ""). The parameter describes how strict the connection manager should be when matching connection parameters to existing pooled connections. strict is the recommend default, and will result in the use of cached connections only when all the connection parameters match exactly. relaxed will result in the use of cached connections when similar connection parameters are used. This can result in increased use of the cache, at the risk of bleeding connection information between (for example) virtual hosts.

Further testing will be merited when time allows, but for now the exceptions are appropriately thrown for a batch executed in a single script.