For 2021 - online Python 3 training - see ((here)).
Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7. We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.
Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc. |
INSERT, DELETE, REPLACE and UPDATE - changing the content of SQL tables
Most enquires of an SQL database are SELECTs - most database are "Read Mostly" and writes are limited to a small proportion of accesses (though there are exceptions). And SELECTs are much more complex that things that insert or change data too.
However, I found myself writing en example on yesterday's MySQL course that shows most of the commands for amending data ...
INSERT to add new rows to a table
DELETE to remove rows from a table
REPLACE to replace complete rows, based on the primary key
UPDATE to alter data within existing rows
See examples of each of them [here].
also:
LOAD to insert a whole series of rows from data in a file
The commands above handle the data itself. If you want to handle the metadata (i.e. the information about the tables, such as their structure), you'll use CREATE TABLE to set up new tables and ALTER to amend the table structre. (written 2010-11-19)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles S152 - SQL Primer as Used in MySQL [158] MySQL - LEFT JOIN and RIGHT JOIN, INNER JOIN and OUTER JOIN - (2004-12-20) [270] NULL in MySQL - (2005-04-06) [494] MySQL - a score of things to remember - (2005-11-12) [502] SELECT in MySQL - choosing the rows you want - (2005-11-22) [515] MySQL - an FAQ - (2005-12-03) [591] Key facts - SQL and MySQL - (2006-02-04) [2240] How do I query a database (MySQL)? - (2009-06-15) [3061] Databases - why data is split into separate tables, and how to join them - (2010-11-20) [4007] Which database should I use? MySQL v SQLite - (2013-02-16)
Some other Articles
On the way to the course this weekComments in and on Perl - a case for extreme OO programmingMelksham Carnival - getting ready for 2011INSERT, DELETE, REPLACE and UPDATE - changing the content of SQL tablesObject Orientation in an hour and other Perl LecturesMacBook Air - hardware and system reviewLots of things to do with and within a C++ classC++ - a complete example with polymorphism, and how to split it into project filesZyliana Kyrei Cox
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