Rushad Nabiullin <email@example.com>
CLIP provides simple but powerful tools for access to the various SQL servers. The underlying principles of this tools are considered in this chapter. Some features and possibilities and related classes and functions are described below.
Some of the features and possibilities are listed below.
CLIP unifies use of the various SQL servers thus hiding individual peculiarities of their APIs from developers as many as possible. Nevertheless you should know SQL dialect of desired RDBMS.
Transactions are supported. By default each SQL statement works in it's own transaction (each statement is enclosed in pair of START/COMMIT implicitly). Nevertheless it is possible to accomplish a sequence of the statements in one transaction by calling explicitly START and COMMIT or ROLLBACK functions in appropriate points.
Local ordering allow change the order of rows locally, no more need to charge the server by almost the same query with different ORDER BY clause. Also, local orders allow fast seek for desired row in huge the result set.
Automation of mirroring updates in database. You may provide appropriate UPDATE, DELETE, INSERT statements which will be executed automaticly after update of the local set of the selected rows.
Two fetch modes - full fetch and fetch on demand. In first mode all result rows are fetched after execution of SELECT statement. The fetching process can be observed and cancelled by user defined function. In second mode the fetching is accomplished as far as particular row has been addressed. Such kind of execution is helpful when amount of result rows can't be estimated.