Oracle Unleashed- P17: When I first started using Oracle many years ago, it was possible to know the database and the tools available. With the rash of recent releases of different options for the database and the spate of new tools, only people who wear their underpants over their trousers will be able to know everything there is to know about the Oracle products. | The objects of Oracle Objects for OLE have their basis in the Data Access Objects DAO of the Microsoft JET SQL engine. JET parses queries and contains its own SQL syntax. JET performs query joins locally using ODBC JET might not be able to make full use of features available in a particular database. JET implements a number of objects used to represent and manipulate the objects of a database. The DAO concepts are good but their implementation is poor and they suffer from having to represent data in the form of flat files up to relational database. Oracle Objects implements some but not all of the DAO but does so from a client server point of view and does so realizing the potential size and organization of Oracle7. Oracle Objects for OLE does not contain its own SQL engine and relies on Oracle7 to parse all queries using its syntax. If an application only needs to communicate with Oracle7 why introduce an intermediate SQL engine with its own syntax Oracle Objects for OLE does not perform local query joins and can access practically all SQL and PL SQL Oracle Procedural Language SQL features. Because Oracle7 can potentially contain millions of rows and because a server is generally more powerful than a client how could you and why would you perform joins locally Finally why not make use of Oracle-specific features and functionality such as PL SQL A larger comparison of the Oracle objects and DAO is done in the following chapter but a brief summary is appropriate here. Discussion of three objects shows the most overlap. These objects are the database the dynaset and the field. Within DAO a database object is used to represent an open database file and a connection to a database as well as to control database-wide permissions and functionality. A dynaset object is used to represent the return set from a SQL select statement. A snapshot object also exists which is basically a read-only dynaset. A field object is used to represent a single column of a query that has .
