[Python-Dev] Re: [DB-SIG] API suggestion: expose 'quote' method

Stuart Bishop zen@shangri-la.dropbear.id.au
Tue, 10 Jun 2003 18:46:18 +1000


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On Thursday, June 5, 2003, at 07:40  PM, M.-A. Lemburg wrote:=0D
=0D
> Magnus Lyck=E5 wrote:=0D
>> At 17:18 2003-06-04 -0700, Chris Cogdon wrote:=0D
>>> So, perhaps what I really should be asking for is to include a =0D
>>> specification for an interface, such as what I've suggested before, =0D=

>>> but make that a OPTIONAL part of the specification. Ie, if it's easy =
=0D
>>> enough to expose, then the driver writers should expose it in the =0D=

>>> standard form.=0D
>>>=0D
>>> Does THAT sound reasonable ?=0D
>> Certainly. Many drivers implement things beyond the mandatory=0D
>> standard, and if it's possible to get the extras compatible=0D
>> across drivers, that's a big bonus in my opinion.=0D
>=0D
> No objection to adding a note to the spec about this. I still=0D
> think that you have to flesh out a reasonable API for this,=0D
> though, e.g. quoting should implemented on a per data type=0D
> basis rather than on a per SQL statement basis.=0D
=0D
Here is a starting point, stolen from Perl's DBI spec (which has=0D
had a fully functional quote method for almost a decade...)=0D
=0D
Translated into Python to avoid abuse ;)=0D
=0D
quote(value)=0D
=0D
     Quote a value for use as a literal value in an SQL statement,=0D
     by escaping any special characters (such as quotation marks) =0D
contained=0D
     within the string and adding the required type of outer quotation =0D=

marks=0D
=0D
     ::=0D
=0D
         >>> 'SELECT foo FROM bar WHERE baz =3D %s' % =
(con.quote("Don't"))=0D
         "SELECT foo FROM bar WHERE baz =3D 'Don''t'"=0D
=0D
     For most database types, quote would return ``'Dont''t'``=0D
     (including the outer quotation marks).=0D
=0D
     A value of ``None`` will be returned as the string ``NULL`` to=0D
     match how NULLs are represented in SQL.=0D
=0D
     Quote will probably *not* be able to deal with all possible input=0D=

     (such as binary data or data containing newlines), and is not =0D
related in=0D
     any way with escaping shell meta-characters. There is no need to =0D=

quote=0D
     values being passed as bound parameters to the ``execute`` or=0D
     ``executemany`` methods.=0D
=0D
quoteidentifier(name)=0D
quoteidentifier(schema, table)=0D
quoteidentifier(catalog, schema, table)=0D
=0D
     Quote an idenntifier (table name etc.) for use in an SQL statement,=0D=

     by escaping any special characters (such as double quotation marks)=0D=

     it contains and adding the required type of outer quotation marks.=0D=

=0D
     Undefined names are ignored and the remainder are quoted and then=0D=

     joined together, typically with a dot (``.``) character. For =0D
example::=0D
=0D
         con.quoteidentifier(None, 'Her schema', 'My table')=0D
=0D
     would, for most database types, return ``"Her schema"."My table"``=0D=

     (including all the double quotation marks).=0D
=0D
     If three names are supplied then the first is assumed to be a =0D
catalog=0D
     name. For example, for Oracle::=0D
=0D
         >>> con.quoteidentifier('link', 'schema', 'table')=0D
         "schema"."table"@"link"=0D
=0D
- -- =0D
Stuart Bishop <zen@shangri-la.dropbear.id.au>=0D
http://shangri-la.dropbear.id.au/=0D
=0D
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