trulens.core.database.migrations¶
🕸✨ Database Migration¶
When upgrading TruLens, it may sometimes be required to migrate the database to incorporate changes in existing database created from the previously installed version. The changes to database schemas is handled by Alembic while some data changes are handled by converters in the data module.
Upgrading to the latest schema revision¶
from trulens.core.session import TruSession
session = TruSession(
database_url="<sqlalchemy_url>",
database_prefix="trulens_" # default, may be omitted
)
session.migrate_database()
Changing database prefix¶
Since 0.28.0, all tables used by TruLens are prefixed with "trulens_"
including the special alembic_version table used for tracking schema changes.
Upgrading to 0.28.0 for the first time will require a migration as specified
above. This migration assumes that the prefix in the existing database was
blank.
If you need to change this prefix after migration, you may need to specify the old prefix when invoking migrate_database:
session = TruSession(
database_url="<sqlalchemy_url>",
database_prefix="new_prefix"
)
session.migrate_database(prior_prefix="old_prefix")
Copying a database¶
Have a look at the help text for copy_database and take into account all the
items under the section Important considerations:
from trulens.core.database.utils import copy_database
help(copy_database)
Copy all data from the source database into an EMPTY target database:
from trulens.core.database.utils import copy_database
copy_database(
src_url="<source_db_url>",
tgt_url="<target_db_url>",
src_prefix="<source_db_prefix>",
tgt_prefix="<target_db_prefix>"
)