Extended usage scenario: Create, Validate, and Add to User Guide

[ckunki]

In the scope of ticket #26 we added a user guide to AAF.

The current ticket requests to enhance the user guide by describing an extended usage scenario (EUS).

Features

Section "Usage" of the user guide should explain that an algorithm is implemented as QueryHandler and what a QueryHandler is.

Demonstrate using

• a temporary file in BucketFS: write and read
• a temporary database table: write and read
• returning the result as database table with more than 1 column

Acceptance Criteria

1. The EUS is Created, Validated (manually), and Added to User Guide
2. The EUS Covers all the features described above
3. There is an integration test verifying that the example is working correctly
4. The existing sample usage image is updated, or another image is added explaining the EUS

[ckunki]

Method start():

1. write parameter+"bucketfs"+time to temp bucketfs file
2. create temp table: add to query_list two more statements:
   a. SelectQuery with CREATE b. SelectQuery with INSERT
3. insert parameter+"table-insert"+time to temp table
4. Return query select from temp table and concat "return"

from datetime import datetime
from exasol.bucketfs import as_string

    def start(self) -> Union[Continue, Finish[str]]:
        def sample_content(key: str) -> str:
            timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
            return f"{timestamp} {key} {self.parameter}"

        self.bfs_proxy = self.query_handler_context.get_temporary_bucketfs_location()
        self._bfs_file(self.bfs_proxy).write(sample_content("bucketfs"))

Method handle_query_result():

1. read result
2. read temp bucketfs file
3. create table from result
4. insert temp bucketfs file content into new table
5. return new table name

    def handle_query_result(self, query_result: QueryResult) -> Union[Continue, Finish[str]]:
        s = as_string(self._bfs_file(self.bfs_proxy).read())

See also

• https://exasol.github.io/bucketfs-python/user_guide/user_guide.html
• https://exasol.github.io/bucketfs-python/user_guide/basics.html#available-converters

[tkilias]

@ckunki Maybe we make actually a test case out of it

[ckunki]

Same thought here :slightly_smiling_face: I added an item to the acceptance criteria