Difference between revisions of "SQL"

From Organic Design
(rm old info and add intro to joins)
(See also: MySQL and utf8mb4)
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*[[Manually backup a wiki]]
 
*[[Manually backup a wiki]]
 
*[[Add a wiki database]]
 
*[[Add a wiki database]]
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== Character sets ==
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*[http://tlug.dnho.net/?q=node/276 Convert a MySQL DB from latin1 to UTF8]
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*[https://mathiasbynens.be/notes/mysql-utf8mb4 MySQL and utf8mb4]
  
 
== See also ==
 
== See also ==
 
*[[MariaDB]]
 
*[[MariaDB]]
 
*[https://stackoverflow.com/questions/5836623/getting-lock-wait-timeout-exceeded-try-restarting-transaction-even-though-im Good thread on table lock problems and solutions]
 
*[https://stackoverflow.com/questions/5836623/getting-lock-wait-timeout-exceeded-try-restarting-transaction-even-though-im Good thread on table lock problems and solutions]
*[http://tlug.dnho.net/?q=node/276 Convert a MySQL DB from latin1 to UTF8]
 
 
*[http://www.sql-tutorial.com/ SQL Tutorial] ''- A nice tutorial on SQL''
 
*[http://www.sql-tutorial.com/ SQL Tutorial] ''- A nice tutorial on SQL''
 
*[http://dev.mysql.com/doc/index.html Official MySQL Documentation]
 
*[http://dev.mysql.com/doc/index.html Official MySQL Documentation]

Revision as of 21:29, 11 November 2018

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SQL (Structured Query Language) is a computer language used to create, retrieve, update and delete data from relational database management systems. SQL has been standardised by both ANSI and ISO.

SQL is commonly spoken either as the names of the letters ess-cue-el, or like the word sequel. The official pronunciation of SQL according to ANSI is ess-cue-el. However, each of the major database products (or projects) containing the letters SQL has its own convention: MySQL is officially and commonly pronounced "My Ess Cue El"; PostgreSQL is expediently pronounced postgres (being the name of the predecessor to PostgreSQL); and Microsoft SQL Server is commonly spoken as Microsoft-sequel-server. See MediaWikiLite for information about SQLite support in MediaWiki, or MSSQL for information about Microsoft SQL Server support. We're now using MariaDB for our SQL server which is a drop-in replacement for MySQL but is fully open source and more efficient too.

Backup & restore

See backup for details about this as it's doesn't outside the SQL environment so doesn't belong in this article. But don't forget to set the default character set to the same as the dump used when you import the data!

To restore only a single database from a full dump use the following:

mysql -D DBNAME -o DBNAME < dump.sql

Fixing crashed tables

To fix a crashed table just use repair TABLENAME from the MySQL command line, or to automatically scan all tables and fix them run the following from the shell.

mysqlcheck --auto-repair DBNAME -u USER -p

Database procedures

Character sets

See also