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The following page has been changed by KevinWilliams:
http://wiki.apache.org/ws/Tuscany/TuscanyJava/DAS_Java_Overview/RDBDAS_Java_User_Guide/Write_Operation_Ordering

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  = Write Operation Ordering =
  
+ Relational databases often use 
[http://en.wikipedia.org/wiki/Referential_integrity Referential Integrity (RI)] 
constraints to maintain database consistency. When RI is enabled, database 
operations must be performed in a specific order that prevents invalid 
references. If this order is not adhered to then the database will throw an 
exception rather than let the write succeed.
  
- Relational databases often use 
[http://en.wikipedia.org/wiki/Referential_integrity Referential Integrity (RI)] 
constraints to maintain database consistency. When using RI, database 
operations must be performed in an order that prevents invalid references. The 
order in which deletes, updates, and inserts are performed in an object model 
may not match the order required by the database.
+ When an application makes modifications to a data graph and then asks the RDB 
DAS to "apply changes", the DAS will create a "batch" of database writes that 
must be sorted and the executed in the correct order to avoid RI Contraint 
exceptions.  A simple example will help here.  Assume a database with two 
tables CUSTOMER and ORDER.  Also assume that the ORDER table has a 
[http://en.wikipedia.org/wiki/Foreign_key foreign key] reference to
  

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