IDS 200 Lecture Notes - Lecture 3: Sql, Nosql, Cloud Database
12 Feb 2020
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Document Summary
A database management system provides for storing and retrieving data such as: The set of users who have "liked" a particular photo. The set of all photos posted by a particular user over the previous two weeks. There are two main approaches to databases" Conceptually, data is stored as a hierarchy of tables, rows, and columns. Tables: the set of records of a particular. Queries are especially important because typical databases read more often more than they write. Ex: "retrieve the complete set of photos viewed yesterday by users from chicago" Sql is the standard language for coding relational database operations. Most often pronounced "sequel"; some prefer s-q-l. It is probably unwise to correct either group. Managing data structure (creating or modifying tables & columns) In order to make each record uniquely identifable within a table, we use key fields. Atomicity means that each database field holds only one element: Ex: suppose a phone number field permits holding mulitple numbers.
