I'd like to propose the attached changes to the DB-API spec. My main
motivation is to make DB-API modules less cumbersome to use when used
directly.
If you want to try it out live, everything except .fetchscalar() is
already implemented in pysqlite. The __enter__/__exit__ thing is in
pysqlite and cx_Oracle.
==> .execute(), .executemany() returning self.
Ability to write shorter code. No more:
cur.execute("select ...")
for row in cur:
...
instead:
for row in cur.exeucte("..."):
...
==> .execute(), .executemany() in connection object.
They should have been placed here anyway. *cough* Users shouldn't have
to mess with cursor objects normally. Ability to write shorter code:
con = module.connect(...)
for row in con.execute("..."):
...
==> __enter__ and __exit__ in the connection object.
Ability to automatically wrap database code in transactions, when using
Python 2.5 or higher:
with con:
con.execute(DML1)
con.execute(DML2)
no more:
try:
cur = con.cursor()
cur.execute(DML1)
cur.execute(DML2)
con.commit()
except:
con.rollback()
==> fetchscalar method in cursor object
This one is low-prio for me, but it's a common use case to only query a
scalar value.
-- Gerhard
*** pep-0249.txt.orig 2008-03-19 13:11:02.000000000 +0100
--- pep-0249.txt 2008-03-19 13:10:57.000000000 +0100
***************
*** 344,354 ****
The parameters may also be specified as list of tuples to
e.g. insert multiple rows in a single operation, but this
kind of usage is deprecated: .executemany() should be used
instead.
! Return values are not defined.
.executemany(operation,seq_of_parameters)
Prepare a database operation (query or command) and then
execute it against all parameter sequences or mappings
--- 344,354 ----
The parameters may also be specified as list of tuples to
e.g. insert multiple rows in a single operation, but this
kind of usage is deprecated: .executemany() should be used
instead.
! This method returns the cursor object.
.executemany(operation,seq_of_parameters)
Prepare a database operation (query or command) and then
execute it against all parameter sequences or mappings
***************
*** 366,376 ****
created by an invocation of the operation.
The same comments as for .execute() also apply accordingly
to this method.
! Return values are not defined.
.fetchone()
Fetch the next row of a query result set, returning a
single sequence, or None when no more data is
--- 366,376 ----
created by an invocation of the operation.
The same comments as for .execute() also apply accordingly
to this method.
! This method returns the cursor object.
.fetchone()
Fetch the next row of a query result set, returning a
single sequence, or None when no more data is
***************
*** 378,387 ****
--- 378,390 ----
An Error (or subclass) exception is raised if the previous
call to .execute*() did not produce any result set or no
call was issued yet.
+ .fetchscalar()
+ This is a wrapper for .fetchone()[0].
+
.fetchmany([size=cursor.arraysize])
Fetch the next set of rows of a query result, returning a
sequence of sequences (e.g. a list of tuples). An empty
sequence is returned when no more rows are available.
***************
*** 804,813 ****
--- 807,836 ----
executed statement modified more than one row, e.g. when
using INSERT with .executemany().
Warning Message: "DB-API extension cursor.lastrowid used"
+ Connection Method .execute
+ This is a shorthand for creating a cursor object by calling .cursor(),
+ then executing the new cursor object's .execute() method with the
+ parameters specified.
+
+ This method returns the newly created cursor object.
+
+ Connection Method .executemany
+ This is a shorthand for creating a cursor object by calling .cursor(),
+ then executing the new cursor object's .executemany() method with the
+ parameters specified.
+
+ This method returns the newly created cursor object.
+
+ Connection Method .__enter__
+ This method returns self.
+
+ Connect Method .__exit__
+ This method is implemented such that it calls .rollback() if any
+ exception has been raised, and .commit() otherwise.
Optional Error Handling Extensions
The core DB API specification only introduces a set of exceptions
which can be raised to report errors to the user. In some cases,
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