COMPSCI 1MD3 Lecture Notes - Lecture 19: Macos, Nosql, Postgresql
9 Apr 2018
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Document Summary
Data is stored in files and loaded as needed, however the data can be larger than the available memory. There is no need to explicitly open files and read data. Data can be accessed simultaneously either locally or remotely. The data never becomes corrupt, even in the case of failure. Data must be structured in specific ways (e. g tables in relational databases) Complex queries can be written in a dedicated query language. Data items and their relationship is stored in tables. A table is a collection of records/rows/objects/entities with fields/values/columns/attributes. Specifies the names and types of the fields of each table. Valid types include integer, real, text, boolean, date. It was first proposed in 1974 for codd"s relational data model from 1970. This language can be used to interact with a database to. Sql also supports transactions, authorization, stored functions. recently, nosql databases for storing differently structured data and cloud storage are becoming popular.
