FreeTDS Development Group

[Зверев Виталий Борисович <VZverev AT genesis.spb.ru>]

Hello James,
I could try to do parser generator such as 'bind param[i] is attribute of 
object..' with yacc style grammar in flex notation. What do you think about 
'embedded SQL parser' (scn2.l) from 
http://examples.oreilly.com/lex/progs.zip, is it fair enough for starting 
point?

Sincerely yours. 
-------------------------------------------------------
Vitaly Zverev, OCP DBA 8&8i
Oracle E-Business Suite &
Infiniband Linux Cluster Administrator
Genesis Ltd., St.Petersburg, Russia

 

> -----Original Message-----
> From: freetds-bounces AT lists.ibiblio.org 
> [mailto:freetds-bounces AT lists.ibiblio.org] On Behalf Of 
> Lowden, James K
> Sent: Saturday, November 12, 2005 2:08 AM
> To: FreeTDS Development Group
> Subject: Re: [freetds] segfault in Perl's Email::Store when 
> using freetds
> 
> > From: Thompson, Bill D (London)
> > Sent: Friday, November 11, 2005 11:20 AM
> > 
> > From the thread it looks very much like DBD:Sybase is using the
> > ct_dynamic() method in ct-library, which supports 
> placeholders as you 
> > say.  It seems to be segmenting on ct_send(CS_DESCRIBE_INPUT).
> > 
> > ct_dynamic() and friends are now implemented in the latest 
> snapshot, 
> > with one significant exception.  Unfortunately, this is the 
> > CS_DESCRIBE_INPUT parameter to ct_send(), when using SQL server.
> > 
> > Sybase supports this functionality by a bespoke TDS message which 
> > describes the number, type etc of your placeholders.  SQL 
> Server has 
> > no means that I could discover of providing this information to a 
> > client.
> 
> Hi Bill, 
> 
> I had a vague feeling I was understating your progress with 
> ct-lib placeholders.  Sorry about that.  Thanks for 
> straightening me out.  
> 
> It looks like the ODBC analog to CS_DESCRIBE_INPUT is 
> SQLDescribeParam().  This link provides sample source code.  
> 
> http://msdn.microsoft.com/library/default.asp?url=/library/en-
> us/odbcsql
> /od_odbc_d_1not.asp
> 
> I see that we don't implement SQLDescribeParam() in our ODBC 
> driver either. :-(
> 
> And I see why. :-(
> 
> I compiled their source against their library made this call:
> 
>       "select * from systypes where name = ? "
> 
> I then called SQLDescribeParam() and used windump to get this answer:
> 
> [log in reply]
> ...      0001 0000 e317 0002 0a75 0073 005f 0065        
> .........u.s._.e
> 0x00d0   006e 0067 006c 0069 0073 0068 0000 ab70        
> .n.g.l.i.s.h...p
> 0x00e0   0047 1600 0001 0027 0043 0068 0061 006e        
> .G.....'.C.h.a.n
> 0x00f0   0067 0065 0064 0020 006c 0061 006e 0067        
> .g.e.d...l.a.n.g
> 0x0100   0075 0061 0067 0065 0020 0073 0065 0074        
> .u.a.g.e...s.e.t
> 0x0110   0074 0069 006e 0067 0020 0074 006f 0020        
> .t.i.n.g...t.o..
> 0x0120   0075 0073 005f 0065 006e 0067 006c 0069        
> .u.s._.e.n.g.l.i
> 0x0130   0073 0068 002e 000b 4100 4300 3200 4b00        
> .s.h....A.C.2.K.
> 0x0140   4100 4d00 4100 3000 3800 3400 3800 0000        
> A.M.A.0.8.4.8...
> 0x0150   00ad 3600 0171 0000 0116 4d00 6900 6300        
> ..6..q....M.i.c.
> 0x0160   7200 6f00 7300 6f00 6600 7400 2000 5300        
> r.o.s.o.f.t...S.
> 0x0170   5100 4c00 2000 5300 6500 7200 7600 6500        
> Q.L...S.e.r.v.e.
> 0x0180   7200 0000 0000 0800 0332 e313 0004 0434        
> r........2.....4
> 0x0190   0030 0039 0036 0004 3400 3000 3900 3600        
> .0.9.6..4.0.9.6.
> 0x01a0   fd00 0000 0000 0000 00                         .........
> 
> [to server]
> 0x0000   4500 00a2 2eb1 4000 8006 0000 0a51 24a0        
> E.....@......Q$.
> 0x0010   0a50 3adc 1252 09c4 39ce de32 cad3 4948        
> .P:..R..9..2..IH
> 0x0020   5018 4205 74b1 0000 0101 007a 0000 0100        
> P.B.t......z....
> 0x0030   5300 4500 5400 2000 4600 4d00 5400 4f00        
> S.E.T...F.M.T.O.
> 0x0040   4e00 4c00 5900 2000 4f00 4e00 2000 7300        
> N.L.Y...O.N...s.
> 0x0050   6500 6c00 6500 6300 7400 2000 2000 6e00        
> e.l.e.c.t.....n.
> 0x0060   6100 6d00 6500 2000 6600 7200 6f00 6d00        
> a.m.e...f.r.o.m.
> 0x0070   2000 7300 7900 7300 7400 7900 7000 6500        
> ..s.y.s.t.y.p.e.
> 0x0080   7300 2000 5300 4500 5400 2000 4600 4d00        
> s...S.E.T...F.M.
> 0x0090   5400 4f00 4e00 4c00 5900 2000 4f00 4600        
> T.O.N.L.Y...O.F.
> 0x00a0   4600                                           F.
> 
> [to client]
> 0x0000   4500 0063 fbfb 4000 7d06 8d7c 0a50 3adc        
> E..c..@.}..|.P:.
> 0x0010   0a51 24a0 09c4 1252 cad3 4948 39ce deac        
> .Q$....R..IH9...
> 0x0020   5018 4274 ee3b 0000 0401 003b 003b 0100        
> P.Bt.;.....;.;..
> 0x0030   fd01 00b9 0000 0000 0081 0100 0001 0a00        
> ................
> 0x0040   e700 0109 0400 0100 046e 0061 006d 0065        
> .........n.a.m.e
> 0x0050   00fd 0100 c100 0000 0000 fd00 00ba 0000        
> ................
> 0x0060   0000 00                                        ...
> 
> [to server]
> 0x0000   4500 0165 2ebf 4000 8006 0000 0a51 24a0        
> E..e..@......Q$.
> 0x0010   0a50 3adc 1252 09c4 39ce deac cad3 4983        
> .P:..R..9.....I.
> 0x0020   5018 41ca 7574 0000 0301 013d 0000 0100        
> P.A.ut.....=....
> 0x0030   ffff 0d00 0000 0001 2604 04ff ffff ff00        
> ........&.......
> 0x0040   0063 2200 0000 0904 0001 0022 0000 0040        
> .c"........"...@
> 0x0050   0050 0031 0020 006e 0076 0061 0072 0063        
> .P.1...n.v.a.r.c
> 0x0060   0068 0061 0072 0028 0031 0032 0038 0029        
> .h.a.r.(.1.2.8.)
> 0x0070   0000 0063 5000 0000 0904 0001 0050 0000        
> ...cP........P..
> 0x0080   0073 0065 006c 0065 0063 0074 0020 002a        
> .s.e.l.e.c.t...*
> 0x0090   0020 0066 0072 006f 006d 0020 0073 0079        
> ...f.r.o.m...s.y
> 0x00a0   0073 0074 0079 0070 0065 0073 0020 0077        
> .s.t.y.p.e.s...w
> 0x00b0   0068 0065 0072 0065 0020 006e 0061 006d        
> .h.e.r.e...n.a.m
> 0x00c0   0065 0020 003d 0020 0040 0050 0031 0020        
> .e...=...@.P.1..
> 0x00d0   0000 00e7 0001 0904 0001 0088 00cd 00cd        
> ................
> 0x00e0   00cd 00cd 00cd 00cd 00cd 00cd 00cd 00cd        
> ................
> 0x00f0   00cd 00cd 00cd 00cd 00cd 00cd 00cd 00cd        
> ................
> 
> As you can see, the Microsoft ODBC driver implements 
> SQLDescribeParam() by  parsing the SQL locally and asking the 
> server for the datatypes of the placeholders.  
> 
> Anybody want to break out lex & yacc and build us a parser?  
> 
> If not, I think we should document that this is basically 
> never going to work.
> 
> --jkl
> 
> 
> 
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