s a developer, how often have you been asked to refactor a SQL statement to increase performance, accommodate changes to database design, support a new database, or for a whole host of other reasons? Often you need to do the refactoring without affecting the results. When you refactor a query
Oracle supports the pushing of predicates into a given view. Suppose you have a set of layered views: –View OneCREATE VIEW vw_layer_oneAS SELECT * FROM emp;– View TwoCREATE VIEW vw_layer_two_dept_100AS SELECT * FROM vw_layer_oneWHERE deptno=100; Then assume you issued this query: SELECT * FROM vw_layer_two_dept_100WHERE empid=100; The predicate in this
Although the CComBSTR = operator is overloaded to make a copy of the string, this is not the case when assigning a CComVariant’s bstrVal member to a CComBSTR. In this case, you need to make an explicit copy: CComVariant bstrTarget;CComBSTR strSource(“test”);// Use CComBSTR::Copy to make a copy// of the source