Cursors to optionally return dict with column names

[darren-martz]

Optionally have one or all cursors return results as a dictionary with the column names as keys.

set every cursor to return dict by default

my_connection.as_dict = True

set one cursor to return dict by default

my_cursor.as_dict = True
for row in my_cursor:
    print(row["mycolumn"])

[codecov-io]

Codecov Report

Merging #235 into master will decrease coverage by 0.72%.
The diff coverage is 55.17%.

@@            Coverage Diff             @@
##           master     #235      +/-   ##
==========================================
- Coverage   99.04%   98.31%   -0.73%     
==========================================
  Files         145      145              
  Lines        3135     3385     +250     
==========================================
+ Hits         3105     3328     +223     
- Misses         30       57      +27

Impacted Files	Coverage Δ
python/turbodbc/cursor.py	94.22% <47.61%> (-4.8%)	⬇️
python/turbodbc/connection.py	95.83% <75%> (-4.17%)	⬇️
cpp/turbodbc_numpy/Library/src/unicode_column.cpp	86.66% <0%> (-13.34%)	⬇️
cpp/turbodbc/Library/src/cursor.cpp	97.05% <0%> (-2.95%)	⬇️
...pp/turbodbc_arrow/Library/src/arrow_result_set.cpp	96.74% <0%> (-1.78%)	⬇️
...bc_python/Library/src/determine_parameter_type.cpp	96.66% <0%> (-1.64%)	⬇️
.../turbodbc_python/Library/src/python_result_set.cpp	93.87% <0%> (-1.58%)	⬇️
...urbodbc_arrow/Library/src/set_arrow_parameters.cpp	94.8% <0%> (-1.46%)	⬇️
...urbodbc_numpy/Library/src/set_numpy_parameters.cpp	99.47% <0%> (-0.53%)	⬇️
...pp/turbodbc/Library/src/result_sets/result_set.cpp	100% <0%> (ø)	⬆️
... and 48 more

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[xhochy]

According to https://www.python.org/dev/peps/pep-0249/#frequently-asked-questions this API was omitted for a reason, we should thus also omit it here, too.

[darren-martz]

According to https://www.python.org/dev/peps/pep-0249/#frequently-asked-questions this API was omitted for a reason, we should thus also omit it here, too.

Unfortunate situation of lowest common denominator. Does it make a difference the default is off and this is optional?

[xhochy]

I would rather provide a separate API that returns the dicts. What about for row in my_cursor.iterrow_dicts() ? And fetchonedict?

[darren-martz]

That can work too, I’ll adjust to whatever is preferred.

One library I used called pymysql allowed the choice of output types over the same APIs. In turbodbc’s case, they would have something like an enum property such as as_type instead of as_dict, then allowed values such as None, Dict, Numpy, Arrow. Just another approach.

Which is preferred?

[xhochy]

I prefer APIs were the types don't depend on the internal state of an object, i.e. having different methods that for each return type. @fjetter @MathMagique feel free to weigh in here.

[fjetter]

I prefer APIs were the types don't depend on the internal state of an object, i.e. having different methods that for each return type.

I feel the same way. In particular we're exercising the principle already for arrow and numpy