In this IOD 2009 talk I spoke together with Dan Galvin on using pureQuery: a new data access platform with some unique features. pureQuery is a practical technology that strikes the balance between high productivity of developers and providing a full control of the database access by not hiding the SQL. These features make it particularly useful for critical enterprise applications where high performance and large amounts of data dictate special attention to the data access layer and where we have witnessed many object-relational mapping technologies underperform. As a leading DB2 z/OS expert, Dan Galvin shines light on some important performance issues of data access technologies for large, mission critical systems using DB2 on System z. We particularly highlight the impact of static SQL and heterogeneous batch, which are missing in other data access solutions.