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PostgreSQL vs NoSQL Why structure matters Cybertec, 2013 Hans-Jürgen Schönig
PostgreSQL vs NoSQL Why structure matters Cybertec, 2013 Hans-Jürgen Schönig

Oracle database concepts A database schema is a logical container
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... • Record -- one row of a relational database table • Field -- one column of a relational database table • Entity (i.e., record) -- a person, place or thing represented in a database table row • Attribute -- a category of information related to an entity • Linking attribute -- common attribute betwee ...
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... In this table, five faulty records are presented: an incorrect input of “DOB” in row 1 and 2, the wrong “Height” unit applied in row 3, and incorrect FirstName value in the last row. Some of the required values like Gender in row 3 and DOB in row 4 are left blank. The age column is a calculated fiel ...
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... than in each database that uses the template, which results in less disk space used by the database. For instance, using the single copy template with a mail template stores all the design information in one place, making users¡¦ mail databases smaller because the databases no longer have to store t ...
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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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