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Execute prepared statements on client side by default #310

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Execute prepared statements on client side by default #310

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1d101a5
Execute prepared statements on client side by default
damian3031 Jan 4, 2023
dab8de2
approach with ClientSession manipulation
damian3031 Jan 5, 2023
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25 changes: 23 additions & 2 deletions trino/dbapi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -336,6 +336,9 @@ def _prepare_statement(self, statement: str, name: str) -> None:
experimental_python_types=self._experimental_pyton_types)
query.execute()

# Approach with directly manipulating on ClientSession
# self._connection._client_session.prepared_statements[name] = statement

def _execute_prepared_statement(
self,
statement_name,
Expand Down Expand Up @@ -426,11 +429,14 @@ def _deallocate_prepared_statement(self, statement_name: str) -> None:
experimental_python_types=self._experimental_pyton_types)
query.execute()

# Approach with directly manipulating on ClientSession
# self._connection._client_session.prepared_statements.pop(statement_name, None)

def _generate_unique_statement_name(self):
return 'st_' + uuid.uuid4().hex.replace('-', '')

def execute(self, operation, params=None):
if params:
def execute(self, operation, params=None, prepared_statements_client_side=True):
if params and not prepared_statements_client_side:
assert isinstance(params, (list, tuple)), (
'params must be a list or tuple containing the query '
'parameter values'
Expand All @@ -454,6 +460,21 @@ def execute(self, operation, params=None):
self._deallocate_prepared_statement(statement_name)

else:
# Approach with parsing on client side
if params:
assert isinstance(params, (list, tuple)), (
'params must be a list or tuple containing the query '
'parameter values'
)

# substitue parameters in query in reversed order
question_mark_positions = [index for index, character in enumerate(operation) if character == '?']
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Alternative to the reverse trick is to use string slicing. maybe that would be slightly more readable?

question_mark_positions.reverse()
for index, value in enumerate(reversed(params)):
operation = "".join([operation[:question_mark_positions[index]],
"'", value, "'",
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The value should not be enclosed by single quotes but use the appropriate type string.

operation[question_mark_positions[index] + 1:]])

self._query = trino.client.TrinoQuery(self._request, sql=operation,
experimental_python_types=self._experimental_pyton_types)
result = self._query.execute()
Expand Down