Database

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Revision as of 08:17, 21 October 2013 by Milk (talk | contribs) (→‎MongoDB)
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General

  • https://en.wikipedia.org/wiki/Database - an organized collection of data. The data are typically organized to model relevant aspects of reality in a way that supports processes requiring this information. For example, modeling the availability of rooms in hotels in a way that supports finding a hotel with vacancies.

Database management systems (DBMSs) are specially designed applications that interact with the user, other applications, and the database itself to capture and analyze data. A general-purpose database management system (DBMS) is a software system designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, PostgreSQL, SQLite, Microsoft SQL Server, Microsoft Access, Oracle, SAP, dBASE, FoxPro, IBM DB2, LibreOffice Base and FileMaker Pro. A database is not generally portable across different DBMS, but different DBMSs can inter-operate by using standards such as SQL and ODBC or JDBC to allow a single application to work with more than one database.

Relational

SQL

MySQL

Connecting

mysql -u username -ppassword -h hostname databasename
  basic connection

Account management

CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass';
CREATE DATABASE [userdatabase];

GRANT all on [userdatabase].* TO '[username]'; [2]
SHOW GRANTS
SHOW GRANTS FOR 'user'@'localhost';
create database wikidb;
grant index, create, select, insert, update, delete, alter, lock tables on wikidb.* to 'wikiuser'@'localhost' identified by 'password';


Create command list for showing user grants [3]

SELECT CONCAT("SHOW GRANTS FOR '",user,"'@'",host,"';") FROM mysql.user WHERE host!='localhost';
FLUSH privileges;
SET PASSWORD FOR 'user'@'localhost' = PASSWORD('mypass');
mysqladmin -u user_name -h host_name password "newpwd"
Password=PASSWORD('NewPassword') WHERE User='root'; FLUSH PRIVILEGES;
mysqld_safe --init-file=rootreset &

DB management

SHOW databases;
USE [db name];

SHOW tables;

SELECT table_schema "Data Base Name", sum( data_length + index_length ) / 1024 / 1024 "Data Base Size in MB" FROM information_schema.TABLES GROUP BY table_schema ;
13.8.1. DESCRIBE provides information about the columns in a table.

Security

Troubleshooting

Admin

mysqladmin create db_name

Backup

Replication

mysqldump

Tools

  • dBug - "PHP version of ColdFusion’s cfdump. Outputs colored and structured tabular variable information. Variable types supported are: Arrays, Classes/Objects, Database and XML Resources."
  • anywhereindb - Sometime we need to find out a small piece of string in big Database. Like where is the configuration is saved, or where is Jon's Date of birth is saved. This code is search all the tables and all the rows and columns in a MYSQL Database. The code is written in PHP. For faster result, we are only searching in the varchar field.

Scripts

./searchreplacedb2cli.php --host localhost --user root --database test --pass "pass"
     --charset utf\-8 --search "findMe" --replace "replaceMe"
--dry-run

Performance

Clients

phpMyAdmin
Other web
wget http://www.adminer.org/latest-mysql-en.php -O adminer.php
wget http://www.adminer.org/latest-en.php -O adminer.php

MariaDB

Fork of MySQL, drop in replacement.

SQLite

PostgreSQL

NoSQL

Redis

See also Server#Redis

Used in the BOA stack for caching.

CouchDB

Couchbase

MongoDB

JavaScript

Other

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NewSQL

Distributed

Social

Other