We currently pick the store type of a property based on its CLR type. While this works well enough for most cases, there are some cases where the same CLR type can be mapped to multiple store types:

• On SQL Server, string can be mapped to nvarchar(4000) (limited length) or to nvarchar(max) (cannot be indexed). See #10975.
• string can also be mapped to json, xml, and other text types in the various relational databases.
• On PostgreSQL, DateTime can be mapped to timestamp with time zone (UTC) or timestamp without time zone (unknown/unspecified/local timezone). On SQL Server, it can be mapped to datetime or datetime2.

We could make this a provider-specific annotation (#10359). Or, if basically all databases allow the store type to be specified via a simple string, we can simply add a StoreType string property directly to VectorStoreRecordProperty.

I don't see this as urgent for the Build release.