The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
With the substantial change of declarative query languages from plain SQL to the so-called “object SQLs”, in particular OQL, there has surprisingly been not much change in the way problems of query representation and optimization for such languages are tackled. We identify some of the difficulties pure algebraic approaches experience when facing object models and the operations defined for them. Calculus-style...
The conceptual development of the rule-based component of the CROQUE query rewrite and optimization system led to the derivation of an ordering of the rules present in the rule base according to their “optimization potential” in order to increase the efficiency of the logical term rewriting [5]. This heuristic may indeed be used for any other rule-based optimizer, too. The major contribution...
This paper describes some concepts for the evaluation and optimization of ODMG-OQL queries. We present a logical object algebra for the internal representation of OQL queries. Different optimization techniques are sketched: factorization of common subexpressions, dependency-based optimization, and query rewriting. Afterwards, our physical algebra is presented and a complex example of the optimization...