CP102 Lecture Notes - Sql, Query Language, Data Cube
Document Summary
Databases: collection of information organized in a manner that allows for convenient retrieval, examples that are non-computer databases: Paper files, phone book, dictionary, day planner, sign-up sheet: terminology, everything is stored in a "table" (or files) Group of related records: a "record" is everything about the person (horizontal) A "field" is a fact about the person (ex. the address field for "mark" contains the word london) Store each category of info in a column: all records have the same fields, just different data stored in those fields. Fields are picky about what can be store in them (data types) Database building blocks: ebay keeps track of millions of items, netflix stores subscriber information. Field size: defines max number of characters that field can hold, if you define field size of 50, space is reserved for 50 characters, tailor field size to length of data it contains to avoid decreased performance.
