# Which Problems Are Solved
As part of going to a relation storage model, we need to implement the
repository for handling sessions and their events.
# How the Problems Are Solved
- Adds a migration step to create the necessary tables and types in the
database.
- Adds the repository implementation for sessions.
- Implements a projection handler for session events to handle the
events written by the old command handlers.
- Updates the `Session` type and `SessionRepository` interface:
- added `CreatorID`
- Adjusted `Delete` method to return amount of affected columns
- Removed sub-repository clumns from the main interface
- Added `CreatorIDCondition`, `ExpirationCondition`, `ExistsFactor` and
`ExistsMetadata`
- Removed `SetUserAgent`
- Methods of `SessionFactor` and `SessionChallenge` have been made
public
- fixed enumer on `SessionFactorType`
- Adds a `JSON` type to the repository package to easy can JSON columns,
resp. jsonb object inside a property of a `JSONArray` object.
- Adds a `NoChange` interface, which can be implemented to signal that a
`Change` interface implementation is not writing any changes to the
statement builder, e.g. `CTEChange`
# Additional Changes
- Fixes the operators enums. `TextOperations` had wrong comments and
`NumberOperations` additionally also had from comparisons.
- Fixes downgrade of migration step 008.
# Additional Context
- closes https://github.com/zitadel/zitadel/issues/10212
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