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The following page has been changed by KevinWilliams: http://wiki.apache.org/ws/WorkingWithRelationships ------------------------------------------------------------------------------ - As metnioned elswhere in this guide, the RDB DAS provides a simple, implicit mapping from SDO Types/Properties to Relational Tables/Columns. So, in the absence of configuration to the otherwise, reading a table named CUSTOMER with columns NAME and ADDRESS will result in a data graph containing SDO !DataObjects of Type CUSTOMER with properties NAME and ADDRESS. + As mentioned elsewhere in this guide, the RDB DAS provides a simple, implicit mapping from SDO Types/Properties to Relational Tables/Columns. So, in the absence of configuration to the otherwise, reading a table named CUSTOMER with columns NAME and ADDRESS will result in a data graph containing SDO !DataObjects of Type CUSTOMER with properties NAME and ADDRESS. This is great for reading entities from a single table but clients often need to read data from related tables for example Customers and their related Orders. The RDB DAS can work with related database tables and reads that span tables produce graphs of related data objects. Continuing with our Customer->Order example, a client can read a set of Customers and related Orders by using a SELECT statement that includes a join as in the following example: @@ -36, +36 @@ </Config> }}} - This config file specifies the primary keys of the related tables and then the relationship between them. It also provides a convienient name for the relationhip. In short, this config specifies that the CUSTOMER table and ANORDER table are related via ANORDERs column named "CUSTOMER_ID" which references CUSTOMERS column named "ID". The name of the relationship is "orders" + This config file specifies the primary keys of the related tables and then the relationship between them. It also provides a convenient name for the relationship. In short, this config specifies that the CUSTOMER table and ANORDER table are related via ANORDERs column named "CUSTOMER_ID" which references CUSTOMERS column named "ID". The name of the relationship is "orders" As a side note, the config in this example is not required since the table definitions follow a "convention" recognized by the DAS. See WorkingWithConventions. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
