Hey guys,thanks for the information and your support.
Using the implementation of Java (postet byMark Rotteveel), the source code
from the Firebird server
(https://searchcode.com/codesearch/view/25432247/)andwith support of
mycolleagues at work, I could understand the process and can now also read
aliases from a statement.
It is important that before the "isc_dsql_sql_info"with
"isc_info_sql_relation_alias"is called, the statementmust be prepared oder
executed.
I solved my problem like this (tested with Firebird 2.1.5.18497 and Firebird
2.5.3.26778):
-- code start --
IBS status;
char result[4096];
char itemsReq[] =
{
// byte order little endian
//c = 1 byte
//h = 2 byte
//d = 4 byte
//s = n bytes string not terminated
isc_info_sql_select, // result = c type
isc_info_sql_describe_vars, // result = c type + h package length + d parameter
count
isc_info_sql_relation_alias, // result = c type + h package length + s alias +
c unknown
};
isc_dsql_sql_info(status.Self(), &mHandle, sizeof(itemsReq), itemsReq,
sizeof(result), result);
if (status.Errors()) throw SQLExceptionImpl(status,
"TableAliases", _("isc_dsql_sql_info failed."));
auto GetStrings = [] (char *buffer, char token, char subtoken) ->
std::vector<std::string>
{
char *p = buffer;
if (*p != token)
throw LogicExceptionImpl("GetStrings", _("Token not found."));
// the first byte is isc_info_sql_select that consists of one byte without
length
++p;
auto FindToken = [] (char token, char *aBuffer) -> char*
{
if (aBuffer == nullptr)
return nullptr;
char* p = aBuffer;
while (*p != isc_info_end)
{
int len;
if (*p == token)
return p;
len = (*gds.Call()->m_vax_integer)(p + 1, 2);
p += (len + 3);
}
return nullptr;
};
std::vector<std::string> results;
std::string strData;
while ((p = FindToken(subtoken, p)) != nullptr)
{
int len;
len = (*gds.Call()->m_vax_integer)(p+1, 2);
strData = std::string(p+3, len);
// skip the string
p += 3 + len;
if (*p == isc_info_sql_describe_end)
++p;
results.push_back(strData);
}
return results;
};
std::vector<std::string> aliases = GetStrings(result, isc_info_sql_select,
isc_info_sql_relation_alias);
-- code end -- This may not be the best implementation, but I wanted to share
my results with all the interested it.With best regards,
Rudolf
Am 16. Dezember 2014, hat Vlad Khorsun <hv...@users.sf.net> geschrieben:
> 16.12.2014 11:13, Mark Rotteveel wrote:
> > On Tue, 16 Dec 2014 11:03:39 +0200, Vlad Khorsun <<hv...@users.sf.net>>
> > wrote:
> > > 16.12.2014 10:27, Rudolf Grauberger wrote:
> > > > I would like to read the table aliases,
> > > >
> > > After call of isc_dsql_prepare() you'll have XSQLDA structure filled
> > > with all
> > > info, including known relation aliases. Read IB6 "API Guide", chapter
> > > "Working
> > > with Dynamic SQL". Guide is available here:
> > >
> > > http://www.firebirdsql.org/en/reference-manuals/
> > >
> > The XSQLDA doesn't include the relation alias, only the relation name (and
> > the column name and alias). So you need to to use sql_info to obtain the
> > relation_alias; isc_info_sql_relation_alias was also only added in Firebird
> > 2.
> >
> You right, i forget about it. Hope, your link helps Rudolf.
>
> Regards,
> Vlad
>
>
>
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