Difference between revisions of "SQL"

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== Common MediaWiki MySQL queries ==
 
== Common MediaWiki MySQL queries ==
 
=== Insert into interwiki ===
 
=== Insert into interwiki ===
−
INSERT INTO interwiki (iw_prefix,iw_url,iw_local) VALUES('example','http://www.example.org/$1',0);
+
{{Code|<PHP>
 +
INSERT INTO interwiki (iw_prefix,iw_url,iw_local)  
 +
VALUES('example','http://www.example.org/$1',0);
 +
</PHP>
 +
}}
 
To delete entry;
 
To delete entry;
−
DELETE FROM interwiki WHERE iw_prefix LIKE "example";
+
{{Code|<PHP>
−
 
+
DELETE FROM interwiki  
 +
WHERE iw_prefix LIKE "example";
 +
</PHP>
 +
}}
 
=== Backup and compress DB & FS ===
 
=== Backup and compress DB & FS ===
 
{{code|
 
{{code|

Revision as of 20:50, 18 November 2008

Template:Merge


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.

Common MediaWiki MySQL queries

Insert into interwiki

<PHP>

INSERT INTO interwiki (iw_prefix,iw_url,iw_local) VALUES('example','http://www.example.org/$1',0); </PHP>

To delete entry;

<PHP>

DELETE FROM interwiki WHERE iw_prefix LIKE "example"; </PHP>

Backup and compress DB & FS

7za a -si backupfile.sql.7z # Backup

tar cf - directory


{{{1}}}

Reset a password

first identify the username you want to reset;

{{{1}}}

Then update that users password. Note that the password is a nested concatenation of both the md5 of the user_id combined with the md5 password.


{{{1}}}

Reset or set a page hit counter

UPDATE page SET page_counter=0 WHERE page_title='Main_Page';

Adjust user groups

INSERT INTO user_groups (ug_user,ug_group) VALUES(999,'sysop');

Selecting current articles by category

See MediaWiki schema for a description of the tables. Essentially categorylinks store the category member relationships , page identifies the title and metadata information, revision identifies al revisions of an article, and text contains the actual wikitext of articles. there is a one to many relationship between pages and revisions, and a one to many relationship between text and revisions.

The database schema used by MediaWiki allows variable article content to be stored as key => value pairs where the atomic unit for the content varies depending on the content of the article. A way around this is to use categorization to group common atomic unit structure together. Basically this is a filtering problem, however queried atomic unit structure needs to be checked downstream by any downstream processing of content within categories.

Example

SELECT old_text FROM 1120_text, 1120_revision
WHERE old_id = rev_text_id and rev_id IN (
SELECT page_latest FROM 1120_page, 1120_categorylinks
WHERE cl_to = "Portal" and cl_from = page_id );

Some SQL queries executable by admin (need fixing to work in new MW1.9.3 environment)

Documentation

MySQL vs MSSQL

MySQL News & Information

Towards SQL for P2P environments

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