Implement filtering options for Text types.

[kgodey]

Problem

We need to ensure that records that include columns of all Text types support the following filters via API:

• contains {x}
• is {x}
• is not {x}
• starts with {x}
• ends with {x}
• does not contain {x}
• does not start with {x}
• does not end with {x}
• is empty
• is not empty

This involves:

• Implementing the filters in the backend
• Updating the /api/v0/databases/<id>/types/ endpoint to store available filters on this type
  • Filter information should include the number of parameters needing to be passed in (e.g. contains needs 1 parameter, is empty needs 0)

Additional context

• We're using our fork of sqlalchemy-filters to provide filtering. See: https://github.com/centerofci/sqlalchemy-filters.
• This issue is blocked by implementation of Text types:
  • Handle VARCHAR data type in the backend. #404
  • Handle TEXT data type in the backend. #405
  • Handle CHAR data type in the backend. #407
• Update filtering issues to cover storing filter/group information in the backend. #557 provides some context on storing filters.

[dmos62]

@kgodey Should we have a way to filter in a case-insensitive manner?

[kgodey]

@dmos62 Yes, we should.