Migration type is only applicable to project using Version Control Workflow.
After project has enabled version control workflow and then starts to onboard its managed database to use this workflow, Bytebase needs to know the current schema state of that live database. This is achieved by using a baseline migration script which includes the entire schema of that live database. This also suggests the first migration to a database should alway be a baseline migration.
For MySQL, the baseline script can be generated by
mysqldump --no-data <<dbname>>
See further details in
Normal migration is just the usual migration scripts containing DDL statements. Please also follow the naming convention so that Bytebase can recognize and figure out which database the migration script applies to.
A branch migration history is recorded when a database is restored from a backup. See Restore from Backup for details.