hormone-therapy
发表于 2025-3-21 16:55:53
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自负的人
发表于 2025-3-21 23:53:26
Textbook 2000nto classical database models and languages such as relational, hierarchical, and network models and languages, and also into object-oriented models. The book is of interest for all database theoreticians as well as practitioners who are provided with the relevant foundations of database modeling.
Proponent
发表于 2025-3-22 00:42:03
https://doi.org/10.1007/978-3-531-90283-8th the use of default assumptions in the case of missing specifications). This points directly to a principal advantage of ER modeling: Modeling a type as a complete item leads to a more complete specification. However for this reason, classical modeling methodologies cannot be applied in the same manner.
国家明智
发表于 2025-3-22 06:05:25
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Moderate
发表于 2025-3-22 10:48:33
ng of database and information systems applications.IncludesDatabase technology and entity-relationship (ER) modeling have meanwhile reached the level of an established technology. This book presents the achievements of research in this field in a comprehensive survey. It deals with the entity-relat
子女
发表于 2025-3-22 13:22:13
Digitales Nomadentum als Lebensstilodologies and database design strategies. We compare this theory with classical approaches developed mainly for relational database models. Furthermore, we discuss how information engineering can be supported by tool boxes.
子女
发表于 2025-3-22 17:05:04
https://doi.org/10.1007/978-3-531-92516-5the examples discussed above. The translation approach introduced below summarizes, generalizes and extends the approaches presented in and .
敬礼
发表于 2025-3-23 01:07:34
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Allure
发表于 2025-3-23 01:42:39
https://doi.org/10.1057/9781137272621 the limitation to 1-n-binary relationship types (functions), led to frightening modeling. Extensions of the model can be safe or unsafe. In Sect. 4 we show how to extend the original ER model to a safe, well-founded and practicable ER model. Due to the problems with pointer or reference semantics we only use set semantics.
aspect
发表于 2025-3-23 05:45:27
Ursula Mense-Petermann,Gabriele Wagnertroduced so far lack formal semantics. The languages based on data structures are similar to network languages and based on a calculus. use a formal definition for semantics of ER types. Different ER languages such as DESPATH, ERROL, ER-LANG (IBM), GDL, GOR-DAS, GQL/ER, LSL, NETUL, SQL/ER have been proposed.