Create mapping document from HMS tables to UC tables.

[FastLee]

Create a "databases" table as part of the assessment.
This table will be used to track database migrations and be used to configure database targets for migration.

Column Name	Type	Description	Default Value
database	string	Original schema of the table
upgrade_assessment	int	0-Manual 1-In Place 2-CTAS 3-Mixed
target_catalog	string	Name of the Target Catalog	ucx_<workspace_id>
target_datbase	string	Name of the Target Database	original database name
workspace_id	string	A workspace ID of the HMS (Optional)
views	int	0-No Views 1-Views present
upgrade_status	int	0-Not Upgraded 1-Failed Upgrade 2-Partial Upgrade 3-Full Upgrade	0
upgrade_messages	string	Json with a list of all the upgrade errors.	empty

[nfx]

@FastLee this configuration cannot be a table, because we don't have a way to edit/add/validate it from UI. But I see the important points on some of the logic. let's discuss them -

1. what creates upgrade_assessment?
2. what defines the target_catalog? what is the source? which process?
3. why do we need target_datbase? why can't it be the original database name?
4. why do we need upgrade_status and upgrade_messages?

[FastLee]

1. The assessment process
2. It defaults to a default catalog for the migration, manually overriden.
3. If we want to redirect
4. To report back from the database migration step. And rerun as needed.

[FastLee]

Let's consider a notebook with UI to allow admins to update this table.

[nfx]

Let's close this issue in favor of resolving the #307.

[FastLee]

I'm reopening this discussion. As we addressed the process in #307 we need to address this issue to make progress on table migrations.

[FastLee]

I would suggest a following.
We create a default mapping for the HMS.
By default all the databases and tables are mapped to a single catalog.
You can override the mapping at the HMS level/Database/Table.
We should annotate just the overrides.
The Structure Should be something like that:

Element	Target	Notes
<Root>	UCX_Dev	Default mapping
Sales	Sales_Dev.Sales	Mapping to a different catalog
Production_Yield	Production.Yield	Overriding the catalog and the database name
Production_Yield.YOY_Yield	Production.Yield.YOY	Overriding the catalog database and table name
Playground	<Skip>	Marking a resource to be skipped

The installer will create a configuration file with a single entry for the workspace. We will create a notebook that will provide a simple interface to override entries.