Initialization and Update of the hybris Commerce Suite

There are two representations of the Type System of the hybris Commerce Suite.

•    There is a file-based representation that is spread across in the various items.xml files of the hybris Commerce Suite extensions. This representation is not actively used by the hybris Commerce Suite at runtime. You can modify this representation at any time by modifying the items.xml file of an extension. However, modifications of the items.xml files only take effect after an initialization or an update of the hybris Commerce Suite.
•    The database of the hybris Commerce Suite also contains a representation of the type system. This representation is actually in use by the hybris Commerce Suite at runtime. The representation in use reflects the state the type system was in when the hybris Commerce Suite was last updated or initialized

Locking the hybris Suite

Hybris Administration Console also allows you to lock the system against initialization or update. While this lock is in effect, the hybris Commerce Suite can neither be updated nor initialized. This lock therefore prevents loss of data. Lock can be activated and deactivated both from theInitialization and the Update page of the hybris Administration Console

Initialization

Initialization drops existing type definitions from the database prior to rebuilding, so the entire type system is created from scratch. So during an initialization, type system definitions are created to match the type system definition in the items.xml files

Initializing the hybris Commerce Suite

Access the Initialization Page

 1.)Open the hybris Administration Console.

2.) Go to the Platform tab and select Initialization option. The Initialization page now displays.

Click the Initialize button. This:

1.) Aborts all running cron jobs

2.) Removes all tables from the database schema. The DROP TABLE statement is used. This removes not only hybris Commerce Suite data, but all data stored in the database schema. Since hybris Commerce Suite version 5.1, during the initialization process the system no longer removes all tables. Now it only removes those tables that are declared in its current items.xml files. Old tables - orphaned data - stay intact

The init process prior to hybris Commerce Suite version 5.1 creates the type system by iterating through all extension managers and calling their methods in this order:

initializeRemoveObjects

initializeCreateTypes

initializeModifyTypes

initializeCreateObjects

3.) The init process in hybris Commerce Suite 5.1 or later prepares the ddl and dml scripts and executes them (unless dryrun is enabled, in which case the scripts are not executed). This way - the schema is prepared and persisted into db. Ddl scripts also remove tables.

4.) Clears cache and Creates a number of media folders

5.) Sets licenses

At this point the type system has been initialized. The Initialization continues with creating essential data and project data (This is optional, but enabled for all extensions by defautl). Furthermore, during the init process the hmc configuration is cleared and types are localized.

You can also initialize the system from the command line by running the command ant initialize.

Update

During an update, type system definitions are modified to match the new type system definition in the items.xml files.  

First and foremost, the update mechanism makes sure that all data that existed in the system before the update is still accessible after the update.

Therefore:

1.)Update preserves the table name, to which a type was mapped, even if it was changed in items.xml

2.)Update preserves the column name, to which an attribute was mapped, even if it was changed in items.xml

3.)Update preserves the column type for an attribute, even if it was changed in items.xml

4.)Update does not drop any tables and columns

5.)Update does not delete any item data, including type instances and type system data (composed types etc.)

6.)Update drops and recreate indices, if they are added or changed in items.xml

7.)Update does NOT change the attribute from optional to mandatory, even if it was changed in items.xml

This is what the process looks like:

• The type system definitions from all extensions items.xml files are read in.
• The hybris Commerce Suite type system in the database is modified according to the type definitions of all extensions items.xml files.

1. Adding newly defined types to the type system definition in the database.Type definitions and attribute definitions that are not part of the type system definition in the database are added.
2. Modifying existing types to match the type system definition in the database.Type definitions and attribute definitions that are changed compared to the type system definition in the database are modified.
3. Again, like in the init process, the old update logic (prior to hybris Commerce Suite 5.1) iterates through extensions and uses extension manager methods to create and modify types. Whereas, in the new update (since hybris Commerce Suite 5.1), ddl and dml scripts are also generated here.
4. Update then continues with creating essential and project data, optionally, if selected.