Author: Mike Nelson
Located at core/data_migration_scripts/EE_DMS_Core_4_5_0.dms.php
Returns whether or not this data migration script can operate on the given version of the database. Eg, if this migration script can migrate from 3.1.26 or higher (but not anything after 4.0.0), and it's passed a string like '3.1.38B', it should return true. If this DMS is to migrate data from an EE3 addon, you will probably want to use EEH_Activation::table_exists() to check for old EE3 tables, and EE_Data_Migration_Manager::get_migration_ran() to check that core was already migrated from EE3 to EE4 (ie, this DMS probably relies on some migration data generated during the Core 4.1.0 DMS. If core didn't run that DMS, you probably don't want to run this DMS). If this DMS migrates data from a previous version of this EE4 addon, just comparing $current_database_state_of[ $this->slug() ] will probably suffice. If this DMS should never migrate data, because it's only used to define the initial database state, just return FALSE (and core's activation process will take care of calling its schema_changes_before_migration() and schema_changes_after_migration() for you. )
Performs database schema changes that need to occur BEFORE the data is migrated. Eg, if we were going to change user passwords from plaintext to encoded versions during this migration, this would probably add a new column called something like "encoded_password".
Methods inherited from EE_Data_Migration_Script_Base
Methods inherited from EE_Data_Migration_Class_Base