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Chapter 1
Chapter 1

... Cursory attempt at conceptual data modeling Define database during development of initial prototype Repeat implementation and maintenance activities with ...
Document
Document

... – A join in which rows that do not have matching values in common columns are nonetheless included in the result table • as opposed to inner join, in which rows must have matching values in order to appear in the result table • Customer record created but the customer has yet to place an order ...
Chapter 9 Relational Database Design by ER- and EER
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Introduction to LINQ
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Continuous Queries and Publish/Subscribe
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... Several kinds of integrity constraints can be expresses in the ER model: key constraints, participation constraints, overlap/covering constraints for ISA hierarchy. Some foreign key constraints are also implicit in the definition of the relationship set ...
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... information without having to know complex structured query languages (e.g., SQL) or prior knowledge about the structures of the underlying data. Keyword search over relational databases finds the answers of the tuples in the databases which are connected through primary/foreign keys and contain que ...
Key-Value Data Model - Victoria University of Wellington
Key-Value Data Model - Victoria University of Wellington

... – Represents a logical progression of the key – value data model where the value part has a recognizable structure – Tables are used for the logical (visual) data representation – Table rows contain sparsely populated columns of data, – Each set of logically related columns forms a column family tha ...
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Relational model



The relational model for database management is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in 1969 by Edgar F. Codd. In the relational model of a database, all data is represented in terms of tuples, grouped into relations. A database organized in terms of the relational model is a relational database.The purpose of the relational model is to provide a declarative method for specifying data and queries: users directly state what information the database contains and what information they want from it, and let the database management system software take care of describing data structures for storing the data and retrieval procedures for answering queries.Most relational databases use the SQL data definition and query language; these systems implement what can be regarded as an engineering approximation to the relational model. A table in an SQL database schema corresponds to a predicate variable; the contents of a table to a relation; key constraints, other constraints, and SQL queries correspond to predicates. However, SQL databases deviate from the relational model in many details, and Codd fiercely argued against deviations that compromise the original principles.
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