Data is saved on the server by initiating a transaction, which relies on several well-defined steps. The sequence of steps must be negotiated in a precise order, and their adequate completion is a must. In case one of these steps fails to complete, the entire transaction is rolled back to prevent data inconsistency issues. A transaction step may fail to complete by any of the following reasons:
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a logical error occurred in the database server (in a storage procedure)
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the memory allocated by the database server was exceeded
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the database server has run out of physical storage space
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the server-client connection was discontinued by network problems, power failures etc.
Data exchanges between clients and the server is low. The data queries that the Routes client sends to the server concern only that data displayed at a specific moment. Data downloaded from the server is stored in a cached memory segment in the client. This is why, when a Routes client requests a set of data to be displayed, it first queries the cache for this data and, if the data is not available, it downloads it from the server.
