ResultSetDrivenDataObjectTypes

RDB DAS uses the database metadata retrieved by ODBC driver to create the set of SDO Types used to construct the data graph returned as a result of a query. ODBC returns the data resulting from a query as a set of rows of column values. The metadata associated with this result set provides information about these values. Table name, column name, column type, etc. are all provided for each returned value.

For example, consider a database with the following table:

TABLE CUSTOMER
      ID         INTEGER
      LASTNAME   VARCHAR(20)
      ADDRESS    VARCHAR(30)

The user might query the database like this:

DASImpl* das = (DASImpl*) DASImpl::getFactory().createDAS(getConnection());
CommandPtr readCustomers = das->createCommand("select * from CUSTOMER where LASTNAME = 'Williams'");
DataObjectPtr root = readCustomers0->executeQuery();

The DAS returns a graph of DataObjects each of Type CUSTOMER and each instance will have three properties: (ID, LASTNAME, ADDRESS). Since this example does not pass the DAS a set of SDO Types to use, the DAS creates the Types dynamically based on the metadata.