Re: Escaping in C-language functions

Hello,

i have a C-language function and need to escape some strings returned
from SPI_getvalue to insert into another query string.
Is there a proper way to do the escaping or should i use
my own functions for that?
Or i'm totally wrong and there's a better way to get the values
from a row and insert it into another table?

Best regards

--
Andreas 'ads' Scherbaum

Andreas Scherbaum wrote:
> Hello,
>
> i have a C-language function and need to escape some strings returned
> from SPI_getvalue to insert into another query string.
> Is there a proper way to do the escaping or should i use
> my own functions for that?
> Or i'm totally wrong and there's a better way to get the values
> from a row and insert it into another table?
>
>
> Best regards
>

If you are using 7.2, see section 1.3.2. (Escaping strings for inclusion
in SQL queries) at:
http://www.us.postgresql.org/users-lounge/docs/7.2/postgres/libpq-exec.html

If you are using < 7.2, you'll have to create your own function. See
fe-exec.c in current sources for the 7.2 function.

Hope this helps,

Joe

Joe Conway wrote:
>
> Andreas Scherbaum wrote:
> > Hello,
> >
> > i have a C-language function and need to escape some strings returned
> > from SPI_getvalue to insert into another query string.
> > Is there a proper way to do the escaping or should i use
> > my own functions for that?
> > Or i'm totally wrong and there's a better way to get the values
> > from a row and insert it into another table?

> If you are using 7.2, see section 1.3.2. (Escaping strings for inclusion
> in SQL queries) at:
> http://www.us.postgresql.org/users-lounge/docs/7.2/postgres/libpq-exec.html
>
> If you are using < 7.2, you'll have to create your own function. See
> fe-exec.c in current sources for the 7.2 function.

I'm inside a C-language function (on the server side), not inside a
application written in C.

Best regards

--
Andreas 'ads' Scherbaum

Andreas Scherbaum wrote:
> Joe Conway wrote:
>
>>Andreas Scherbaum wrote:
>>
>>>Hello,
>>>
>>>i have a C-language function and need to escape some strings returned
>>>from SPI_getvalue to insert into another query string.
>>>Is there a proper way to do the escaping or should i use
>>>my own functions for that?
>>>Or i'm totally wrong and there's a better way to get the values
>>>from a row and insert it into another table?
>>
>
>>If you are using 7.2, see section 1.3.2. (Escaping strings for inclusion
>>in SQL queries) at:
>>http://www.us.postgresql.org/users-lounge/docs/7.2/postgres/libpq-exec.html
>>
>>If you are using < 7.2, you'll have to create your own function. See
>>fe-exec.c in current sources for the 7.2 function.
>
>
> I'm inside a C-language function (on the server side), not inside a
> application written in C.
>

Oops, sorry. I guess I should have inferred that from SPI_getvalue. I
don't know of anything in the backend to help you, but I suppose you
could cut-and-paste from fe-exec.c

Joe

Joe Conway wrote:
> Andreas Scherbaum wrote:
> > Joe Conway wrote:
> >
> >>Andreas Scherbaum wrote:
> >>
> >>>Hello,
> >>>
> >>>i have a C-language function and need to escape some strings returned
> >>>from SPI_getvalue to insert into another query string.
> >>>Is there a proper way to do the escaping or should i use
> >>>my own functions for that?
> >>>Or i'm totally wrong and there's a better way to get the values
> >>>from a row and insert it into another table?
> >>
> >
> >>If you are using 7.2, see section 1.3.2. (Escaping strings for inclusion
> >>in SQL queries) at:
> >>http://www.us.postgresql.org/users-lounge/docs/7.2/postgres/libpq-exec.html
> >>
> >>If you are using < 7.2, you'll have to create your own function. See
> >>fe-exec.c in current sources for the 7.2 function.
> >
> >
> > I'm inside a C-language function (on the server side), not inside a
> > application written in C.
> >
>
> Oops, sorry. I guess I should have inferred that from SPI_getvalue. I
> don't know of anything in the backend to help you, but I suppose you
> could cut-and-paste from fe-exec.c

There is a builtin function

quote_literal(text) returns text

That'll do.

Jan

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Jan Wieck wrote:

> > >>>i have a C-language function and need to escape some strings returned
> > >>>from SPI_getvalue to insert into another query string.
> > >>>Is there a proper way to do the escaping or should i use
> > >>>my own functions for that?
> > >>>Or i'm totally wrong and there's a better way to get the values
> > >>>from a row and insert it into another table?
> > >>
> > >
> > >>If you are using 7.2, see section 1.3.2. (Escaping strings for inclusion
> > >>in SQL queries) at:
> > >>http://www.us.postgresql.org/users-lounge/docs/7.2/postgres/libpq-exec.html
> > >>
> > >>If you are using < 7.2, you'll have to create your own function. See
> > >>fe-exec.c in current sources for the 7.2 function.
> > >
> > >
> > > I'm inside a C-language function (on the server side), not inside a
> > > application written in C.

[...]

> There is a builtin function
>
> quote_literal(text) returns text

Any idea (or a short example code) how to use this function inside
a trigger function written in C?

The value is returned from SPI_getbinval (Datum) or SPI_getvalue (char i
think).
But in the last method i have a problem with \0.

Best regards

--
Andreas 'ads' Scherbaum