Data Tier
The data tier encompasses a large number of data sources. These sources can be relational databases, directory services, messaging systems, legacy systems, or user-defined data providers. The data tier is actually the COM interfaces to these data stores. The components in this tier ensure data integrity and provide a consistent interface .
Transactions
When we talk about transactions we are referring to several individual tasks grouped together as a single unit of work where all tasks successfully complete or all fail. The classic example is when you transfer money from one account to another. This includes two tasks, taking money out of one account and putting it into another. If the first task worked and the second did not this ...
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