MySQL Learning (a) MySQL database

1. What is a database?

A database is organized by data structure. Warehouse where data is stored and managed

2. Relational database management system (relational DB Management system i.e. RDBMS)

The so-called relational database is a database based on the relational type. Processing data in a database with mathematical concepts and methods such as set algebra

Features of the RDBMS:

A. The data appears in tabular form.

B. Various record names for each behavior

C. data fields corresponding to record names for each column

D. A number of rows and columns form a single table

e. A number of single-table components databse

RBDMS terminology

database: The database is a collection of some associated tables

data table: a table is a matrix of data. A table in a database looks like a simple spreadsheet

columns: a column (a data element) that contains the same data, such as a postal code

row: a row (= tuple, or record) is a set of related data, such as a user's subscribed data

redundancy: stores twice times the data, redundancy reduces performance, but improves security

PRIMARY key: The primary key is unique. A table can contain only one primary key. You can use the primary key to query the data

foreign key: foreign key for associating two tables

Composite key: composite key (key combination) multiple columns as an index key, typically used for composite indexes

index: use an index to quickly access specific information in a database table. An index is a structure that sorts the values of one or more columns in a database table. A directory similar to a book

referential integrity: references to non-existent entities are not allowed in referential integrity requirements relationships. The integrity constraints that the relational model must meet in order to ensure the consistency of the data

3.Mysql Database

MySQL is a relational database management system.

MySQL Learning (a) MySQL database