MoodleDocs - User contributions [en]

Database

2012-04-19T17:11:03Z

Jk3us: /* Database structures */

==Database structures==

To help you create tables that meet these guidelines, we recommend you use the built in [[XMLDB_defining_an_XML_structure#The_XMLDB_editor|database definition (XMLDB) editor]].

# Every table must have an auto-incrementing id field (INT10) as primary key. (see [[IdColumnReasons]])
# The main table containing instances of each module must have the same name as the module (eg widget) and contain the following minimum fields:
#* id - as described above
#* course - the id of the course that each instance belongs to
#* name - the full name of each instance of the module
# Other tables associated with a module that contain information about 'things' should be named widget_things (note the plural).
# Core tables in general should have single word names non-pluralised, and double word names pluralised only for the last letter e.g. 'course', 'course_categories'. The only exceptions should be for reserved words e.g. 'files'. Some tables don't fit this pattern right now for historical reasons, but this will eventually be changed.
# Table and column names should avoid using [[Database reserved words|reserved words in any database]]. Please check them before creation. Table names may be up to 28 characters long, and Column names up to 30 characters.
# Column names should be always lowercase, simple and short, following the same rules as for variable names.
# Where possible, columns that contain a reference to the id field of another table (eg widget) should be called widgetid. (Note that this convention is newish and not followed in some older tables)
# Boolean fields should be implemented as small integer fields (eg INT4) containing 0 or 1, to allow for later expansion of values if necessary.
# Most tables should have a timemodified field (INT10) which is updated with a current timestamp obtained with the PHP time() function.
# Always define a default value for each field (and make it sensible)
# Each table name should start with the database prefix ($CFG->prefix). In a lot of cases, this is taken care of for you automatically. Also, under Postgres, the name of every index must start with the prefix too.
# In order to guarantee [[XMLDB problems#Table and column aliases - the AS keyword|cross-db compatibility]] follow these simple rules about the use of the '''AS''' keyword (only if you need table/column aliases, of course):
#* '''Don't use''' the '''AS''' keyword for '''table aliases'''.
#* '''Do use''' the '''AS''' keyword for '''column aliases'''.
# '''Never''' create UNIQUE KEYs (constraints) at all. Instead use UNIQUE INDEXes. In the future, if we decide to add referential integrity to Moodle and we need UNIQUE KEYs they will be used, but not now. Please note that the XMLDB editor allows you to specify both XMLDB-only UNIQUE and FOREIGN constraints (and that's good, in order to have the XML well defined) but only underlying INDEXes will be generated.
# Those XMLDB-only UNIQUE KEYs (read previous point) only must be defined if such field/fields '''are going to be the target''' for some (XMLDB-only too) FOREIGN KEY. Else, create them as simple UNIQUE INDEXes.
# Tables associated '''with one block''' must follow this convention with their names: '''$CFG->prefix + "block_" + name_of_the_block + anything_else'''. For example, assuming that $CFG->prefix is 'mdl_', all the tables for the block "rss_client" must start by 'mdl_block_rss_client' (being possible to add more words at the end, i.e. 'mdl_block_rss_client_anothertable'...). This rule will be 100% enforced with Moodle 2.0, giving time to developers until then. See [http://tracker.moodle.org/browse/MDL-6786 Task 6786] for more info about this.
# '''Never''' make database changes in the STABLE branches. If we did, then users upgrading from one stable version to the next would have duplicate changes occurring, which may cause serious errors.
# When refering to integer variable in SQL queries, do not surround the value in quotes. For example, get_records_select('question', "category=$catid") is right. get_records_select('question', "category='$catid'") is wrong. It hides bugs where $catid is undefined. ([http://moodle.org/mod/forum/discuss.php?d=80629 This thread explains].)
# Never use double quotes for variable values in SQL queries (e.g. <strike>'SELECT * FROM {user} WHERE username = "someuser"'</strike>). While this is OK for MySQL, which does not respect ANSI standard for databases, Postgresql is treating double quoted variable this as system identifier (e.g. field name).
# Moodle does not support database "views", don't use them. See Petr's comment on [http://tracker.moodle.org/browse/MDL-25407 Task 25407] for more info about this.

[[Category:Coding guidelines|Database]]
[[Category:DB|Database]]
[[Category:XMLDB|Database]]

Database

2012-04-19T17:10:27Z

Jk3us: /* Database structures */

==Database structures==

To help you create tables that meet these guidelines, we recommend you use the built in [[XMLDB_defining_an_XML_structure#The_XMLDB_editor|database definition (XMLDB) editor]].

# Every table must have an auto-incrementing id field (INT10) as primary key. (see [[IdColumnReasons]])
# The main table containing instances of each module must have the same name as the module (eg widget) and contain the following minimum fields:
#* id - as described above
#* course - the id of the course that each instance belongs to
#* name - the full name of each instance of the module
# Other tables associated with a module that contain information about 'things' should be named widget_things (note the plural).
# Core tables in general should have single word names non-pluralised, and double word names pluralised only for the last letter e.g. 'course', 'course_categories'. The only exceptions should be for reserved words e.g. 'files'. Some tables don't fit this pattern right now for historical reasons, but this will eventually be changed.
# Table and column names should avoid using [[Database reserved words|reserved words in any database]]. Please check them before creation. Table names may be up to 28 characters long, and Column names up to 30 characters.
# Column names should be always lowercase, simple and short, following the same rules as for variable names.
# Where possible, columns that contain a reference to the id field of another table (eg widget) should be called widgetid. (Note that this convention is newish and not followed in some older tables)
# Boolean fields should be implemented as small integer fields (eg INT4) containing 0 or 1, to allow for later expansion of values if necessary.
# Most tables should have a timemodified field (INT10) which is updated with a current timestamp obtained with the PHP time() function.
# Always define a default value for each field (and make it sensible)
# Each table name should start with the database prefix ($CFG->prefix). In a lot of cases, this is taken care of for you automatically. Also, under Postgres, the name of every index must start with the prefix too.
# In order to guarantee [[XMLDB problems#Table and column aliases - the AS keyword|cross-db compatibility]] follow these simple rules about the use of the '''AS''' keyword (only if you need table/column aliases, of course):
#* '''Don't use''' the '''AS''' keyword for '''table aliases'''.
#* '''Do use''' the '''AS''' keyword for '''column aliases'''.
# '''Never''' create UNIQUE KEYs (constraints) at all. Instead use UNIQUE INDEXes. In the future, if we decide to add referential integrity to Moodle and we need UNIQUE KEYs they will be used, but not now. Please note that the XMLDB editor allows you to specify both XMLDB-only UNIQUE and FOREIGN constraints (and that's good, in order to have the XML well defined) but only underlying INDEXes will be generated.
# Those XMLDB-only UNIQUE KEYs (read previous point) only must be defined if such field/fields '''are going to be the target''' for some (XMLDB-only too) FOREIGN KEY. Else, create them as simple UNIQUE INDEXes.
# Tables associated '''with one block''' must follow this convention with their names: '''$CFG->prefix + "block_" + name_of_the_block + anything_else'''. For example, assuming that $CFG->prefix is 'mdl_', all the tables for the block "rss_client" must start by 'mdl_block_rss_client' (being possible to add more words at the end, i.e. 'mdl_block_rss_client_anothertable'...). This rule will be 100% enforced with Moodle 2.0, giving time to developers until then. See [http://tracker.moodle.org/browse/MDL-6786 Task 6786] for more info about this.
# '''Never''' make database changes in the STABLE branches. If we did, then users upgrading from one stable version to the next would have duplicate changes occurring, which may cause serious errors.
# When refering to integer variable in SQL queries, do not surround the value in quotes. For example, get_records_select('question', "category=$catid") is right. get_records_select('question', "category='$catid'") is wrong. It hides bugs where $catid is undefined. ([http://moodle.org/mod/forum/discuss.php?d=80629 This thread explains].)
# Never use double quotes for variable values in SQL queries (e.g. <strike>'SELECT * FROM {user} WHERE username = "someuser"'</strike>). While this is OK for MySQL, which does not respect ANSI standard for databases, Postgresql is treating double quoted variable this as system identifier (e.g. field name).
# Moodle does not support database "views", don't use them. See [http://tracker.moodle.org/browse/MDL-25407 Task 25407] for more info about this.

[[Category:Coding guidelines|Database]]
[[Category:DB|Database]]
[[Category:XMLDB|Database]]

UTF-8 migration

2011-03-09T20:50:36Z

Jk3us:

The goal for this pages is to have a real roadmap for the migration of Moodle to UTF-8. This includes both language packages and DB contents. Every step in the roadmap must be documented to explain all the alternatives and potential problems we find and their solutions.

==Moodle migration to UTF-8 - General roadmap and detailed implementation plan==

* [[UTF-8 justification|Justification and preliminary work]] - Why we must start the migration to an UTF-8 environment and how we are going to organise the whole thing.

* [[UTF-8 info gathering|Gathering detailed information]] - How we can obtain detailed information from moodlers around the world and how to use it.

* [[UTF-8 lang files|Moving language files]] - How to do the work with current lang files, new structures and strings, downloads...

* [[UTF-8 DB|Converting the DB]] - The long process of converting all the structures and contents inside Moodle DB to UTF-8.

* [[UTF-8 PostgreSQL|PostgreSQL notes]] - Special notes and howtos for PostgreSQL users.

* [[UTF-8 scripts|Recoding PHP scripts]] - Functionalities and scripts to modify in order to work under UTF-8.

* [[UTF-8 problems|Problems]] - Outline big problems during db migration, and possible solutions.

* [[UTF-8 contrib|contrib]] - A simple outline of what needs to be done to make a module work with the migration.

==See Also==

* [[Converting your MySQL database to UTF8]]

[[Category:UTF-8]]

Talk:Blocks

2011-03-07T22:12:25Z

Jk3us: /* Element names */

This page is for reporting errors, suggesting improvements, etc. Feel free to contribute!

== "Notifications" ==

At this part: "At this point our block should be capable of being automatically installed in Moodle and added to courses; visit your administration page to install it and after seeing it in action come back to continue our tutorial."

This is not clear since Moodle no longer has a single administration page.

More to the point would say to go to the /admin/index.php page for your Moodle install. On my latest version of Moodle 1.8 the link in the Administration block is labeled "Notifications".

== Splitting up ==

I split the page up into sub pages because I got an error message that the page was over 32 KB. The three appendixes are now separate pages. --[[User:Frank Ralf|Frank Ralf]] 12:16, 26 January 2009 (CST)

== Increasing readability ==
* Colored the code
* Inserted some line breaks
* Amended the appendixes --[[User:Frank Ralf|Frank Ralf]] 16:24, 6 February 2009 (CST)
* Started correcting the old links (Blocks_howto) --[[User:Frank Ralf|Frank Ralf]] 16:24, 6 February 2009 (CST)

== New new settings.php method ==
There is a new settings.php method to do this, I don't know that much about it, so could someone who does change this page please?--[[User:Mike Worth|Mike Worth]] 05:01, 28 January 2009 (CST)

: When was this feature added? I'm having issues with my block with seemingly multiple Moodle 1.9 installs not being able to display the settings page. Could we have '''any''' documentation on this?--[[User:Jonathan Doane|Jonathan Doane]] 13:26, 30 August 2010 (EST)

:: See [[User_talk:Frank_Ralf/Experience_of_converting_a_module_to_Moodle_2]] for an example. --[[User:Frank Ralf|Frank Ralf]] 19:40, 16 November 2010 (UTC)

== block_simplehtml ==

* I had to title my first file block_simplehtml.php to get it to install. Is this always true?
* For answer see [[User talk:Colin Matheson]]. --[[User:Frank Ralf|Frank Ralf]] 08:54, 1 March 2009 (CST)

== get_config() ?? ==

No mention of get_config() anywhere? {{Unsigned|Jeffrey Silverman}}
: Thanks for the hint, Jeffrey! Will be added to the TODO list. For the time being I added some direct links to http://xref.moodle.org on [[Guidelines_for_contributed_code#Does_the_code_use_the_config_plugins_table.3F]] (Please sign your comments.) --[[User:Frank Ralf|Frank Ralf]] 10:03, 29 March 2009 (UTC)

== How to set Strings (Language) ==

Maybe nice to have: A link or description how to set Language-Strings for the block_simplehtml.
{{Unsigned|Jan Roth}}
: Hi Jan, please have a look at [http://dev.moodle.org/mod/resource/view.php?id=48 Moodle Programming > Unit 7 - Part A - Block Basics] which is sort of a follow-up to this docs. And you will find additional information at [[Places to search for lang strings]]. And please sign your comments - second button from the right ;-) --[[User:Frank Ralf|Frank Ralf]] 14:43, 19 January 2010 (UTC)

== Element names ==

Apparently, element names inside a specific_definition form have to start with "config_", I was lucky that I figure this out, it isn't documented anywhere.
--[[User:Jay Knight|Jay Knight]] 22:12, 7 March 2011 (UTC)

Talk:Blocks

2011-03-07T22:12:07Z

Jk3us: /* Element names */ new section