docs/source/python/recipe/driver_manager_prepare.py

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# RECIPE CATEGORY: driver manager
# RECIPE KEYWORDS: prepared statements
# RECIPE STARTS HERE
#: The DBAPI bindings prepare all statements before execution, because of this
#: part of the `DB-API specification`_:
#:
#:     A reference to the operation will be retained by the cursor. If the same
#:     operation object is passed in again, then the cursor can optimize its
#:     behavior.
#:
#: However, you may want to prepare the statement yourself, mostly because this
#: will give you the schema of the parameters (if supported by the server).
#: This can be done with :meth:`Cursor.adbc_prepare
#: <adbc_driver_manager.dbapi.Cursor.adbc_prepare>`.
#:
#: We'll demo this with the SQLite driver, though other drivers also support
#: this.
#:
#: .. _DB-API specification: https://peps.python.org/pep-0249/#id19

import pyarrow

from adbc_driver_manager import dbapi

conn = dbapi.connect("sqlite")

with conn.cursor() as cur:
    param_schema = cur.adbc_prepare("SELECT ? + 1")
    assert param_schema == pyarrow.schema([("0", "null")])

    #: Note that the type of the parameter here is NULL, because the driver
    #: does not know the exact type.

    #: If we now execute the same query with the parameter, the statement will
    #: not be prepared a second time.

    cur.execute("SELECT ? + 1", parameters=(1,))
    assert cur.fetchone() == (2,)

    cur.execute("SELECT ? + 1", parameters=(41,))
    assert cur.fetchone() == (42,)

conn.close()