--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/book/en/B0040-migration.en.txt Tue Dec 23 13:20:14 2008 -0800
@@ -0,0 +1,211 @@
+.. -*- coding: utf-8 -*-
+
+.. _migration:
+
+Migration
+=========
+
+One of the main concept in `CubicWeb` is to create incremental applications
+and for this purpose multiple actions are provided to facilitate the improvement
+of an application and in particular changes applied to the data model
+without loosing existing data.
+
+The current version of an application model is provided in the file
+`__pkginfo__.py` as a tuple of 3 integers.
+
+Migration scripts management
+----------------------------
+
+Migration scripts needs to be located in the directory `migration` of your
+application and nammed accordingly:
+
+::
+
+ <version n° X.Y.Z>[_<description>]_<mode>.py
+
+in which :
+
+* X.Y.Z is the model version number to which the script enable to migrate
+
+* *mode* (between the last "_" and the extension ".py") indicates which part
+ of the application (RQL server, web server) the script applies to in case
+ of distributed installation. Its value could be :
+
+ * `common`, applies to the RQL server as well as the web server and updates
+ files on the hard drive (configuration files migration for example).
+
+ * `web`, applies only to the web server and updates files on the hard drive
+
+ * `repository`, applies only to the RQL server and updates files on the
+ hard drive
+
+ * `Any`, applies only to the RQL server and updates data in the database
+ (schema and data migration for example)
+
+Again in the directory `migration`, the file `depends.map` allows to indicate
+that to migrate to a particular model version, you always have to first migrate
+to a particular `CubicWeb` version. This file can contains comments (lines
+starting by `#`) and a dependancy is listed as follows: ::
+
+ <model version n° X.Y.Z> : <cubicweb version n° X.Y.Z>
+
+For example: ::
+
+ 0.12.0: 2.26.0
+ 0.13.0: 2.27.0
+ # 0.14 works with 2.27 <= erudi <= 2.28 at least
+ 0.15.0: 2.28.0
+
+Base context
+------------
+
+The following identifiers are pre-defined in the migration scripts:
+
+* `config`, instance configuration
+
+* `interactive_mode`, boolean indicating that the script is executed in
+ an intercative mode or not
+
+* `appltemplversion`, application model version of the instance
+
+* `applerudiversion`, cubicweb instance version
+
+* `templversion`, installed application model version
+
+* `erudiversion`, installed cubicweb version
+
+* `confirm(question)`, function interrogating the user and returning true
+ if the user answers yes, false otherwise (always returns true when in a
+ non-interactive mode)
+
+* `_`, function fonction equivalent to `unicode` allowing to flag the strings
+ to internationalize in the migration scripts
+
+In the `repository` scripts, the following identifiers are also defined:
+
+* `checkpoint`, request confirming and executing a "commit" at checking point
+
+* `repo_schema`, instance persisting schema (e.g. instance schema of the
+ current migration)
+
+* `newschema`, installed schema on the file system (e.g. schema of
+ the updated model and erudi)
+
+* `sqlcursor`, SQL cursor for very rare cases where it is really
+ necessary or beneficial to go through the sql
+
+* `repo`, repository object
+
+
+Schema migration
+----------------
+The following functions for schema migration are available in the `repository`
+scripts:
+
+* `add_attribute(etype, attrname, attrtype=None, commit=True)`, adds a new
+ attribute to an existing entity type. If the attribute type is not specified,
+ then it is extracted from the updated schema.
+
+* `drop_attribute(etype, attrname, commit=True)`, removes an attribute from an
+ existing entity type.
+
+* `rename_attribute(etype, oldname, newname, commit=True)`, rename an attribute
+
+* `add_entity_type(etype, auto=True, commit=True)`, adds a new entity type.
+ If `auto` is True, all the relations using this entity type and having a known
+ entity type on the other hand will automatically be added.
+
+* `drop_entity_type(etype, commit=True)`, removes an entity type and all the
+ relations using it.
+
+* `rename_entity_type(oldname, newname, commit=True)`, renames an entity type
+
+* `add_relation_type(rtype, addrdef=True, commit=True)`, adds a new relation
+ type. If `addrdef` is True, all the relations definitions of this type will
+ be added.
+
+* `drop_relation_type(rtype, commit=True)`, removes a relation type and all the
+ definitions of this type.
+
+* `rename_relation(oldname, newname, commit=True)`, renames a relation.
+
+* `add_relation_definition(subjtype, rtype, objtype, commit=True)`, adds a new
+ relation definition.
+
+* `drop_relation_definition(subjtype, rtype, objtype, commit=True)`, removes
+ a relation definition.
+
+* `synchronize_permissions(ertype, commit=True)`, synchronizes permissions on
+ an entity type or relation type.
+
+* `synchronize_rschema(rtype, commit=True)`, synchronizes properties and permissions
+ on a relation type.
+
+* `synchronize_eschema(etype, commit=True)`, synchronizes properties and persmissions
+ on an entity type.
+
+* `synchronize_schema(commit=True)`, synchronizes the persisting schema with the
+ updated schema (but without adding or removing new entity types, relations types
+ or even relations definitions).
+
+* `change_relation_props(subjtype, rtype, objtype, commit=True, **kwargs)`, changes
+ properties of a relation definition by using the nammed parameters of the properties
+ to change.
+
+* `set_widget(etype, rtype, widget, commit=True)`, changes the widget used for the
+ relation <rtype> of entity type <etype>.
+
+* `set_size_constraint(etype, rtype, size, commit=True)`, changes the size constraints
+ for the relation <rtype> of entity type <etype>.
+
+Data migration
+--------------
+The following functions for data migration are available in the `repository` scripts:
+
+* `rql(rql, kwargs=None, cachekey=None, ask_confirm=True)`, executes an arbitrary RQL
+ query, either to interrogate or update. A result set object is returned.
+
+* `add_entity(etype, *args, **kwargs)`, adds a nes entity type of the given
+ type. The attributes and relations values are specified using the nammed and
+ positionned parameters.
+
+Workflow creation
+-----------------
+
+The following functions for workflow creation are available in the `repository`
+scripts:
+
+* `add_state(name, stateof, initial=False, commit=False, **kwargs)`, adds a new state
+ in the workflow.
+
+* `add_transition(name, transitionof, fromstates, tostate, requiredgroups=(), commit=False, **kwargs)`,
+ adds a new transition in the workflow.
+
+You can find more details about workflows in the chapter :ref:`Workflow` .
+
+Configuration migration
+-----------------------
+
+The following functions for configuration migration are available in all the
+scripts:
+
+* `option_renamed(oldname, newname)`, indicates that an option has been renammed
+
+* `option_group_change(option, oldgroup, newgroup)`, indicates that an option does not
+ belong anymore to the same group.
+
+* `option_added(oldname, newname)`, indicates that an option has been added.
+
+* `option_removed(oldname, newname)`, indicates that an option has been deleted.
+
+
+Others migration functions
+--------------------------
+Those functions are only used for low level operations that could not be
+accomplished otherwise or to repair damaged databases during interactive
+session. They are available in the `repository` scripts:
+
+* `sqlexec(sql, args=None, ask_confirm=True)`, executes an arbitrary SQL query
+* `add_entity_type_table(etype, commit=True)`
+* `add_relation_type_table(rtype, commit=True)`
+* `uninline_relation(rtype, commit=True)`