Hi,
In my first exemple, row is updated each time fetch is called and it
doesn't not contains all resulting rows. This is the same in the second
example: m_name and ystr are updated on each fetch call.
Developer has to take care of column type. When you are using soci::row,
if you do not give correct type, row.get or row.operator>> will raise an
exception.
If you don't know the type in advance you can use
row.get_properties(col_id).get_data_type() to retrieve it dynamically.
Arnaud
On 12/07/2015 13:48, Sonya Blade wrote:
Hi,
Thanks in advance, I noticed that statement section in soci web site
rowset seems what I need but your solution is
elegant also, running quick eye in your example: I didn't know that
resulting row can contain more than one row in
your code you actually iterate through all the rows contained in row
object. Does my code interpretation is correct ?
I'd like to know also that who is reponsible for type checking, for
example what about if the 3rd column in row is not double , does it
require
of developer to know that before hand ?
Regards,
------------------------------------------------------------------------
Date: Sun, 12 Jul 2015 13:36:33 +0200
From: [email protected]
To: [email protected]
Subject: Re: [soci-devel] How to iterate through rows of resulting
database.
Hi,
You can use statement to iterate over all rows (see
http://soci.sourceforge.net/doc/3.2/statements.html):
int main()
{
session sql(firebird, "service=D:/New_DB.FDB user=SYSDBA
password=masterkey");
row r;
std::string m_name;
double ystr;
soci::statement stmt = (sql.prepare << "select * from materials",
into(r));
stmt.execute(false); // false to not fetch any data until loop
while(stmt.fetch())
{
r >> m_name >> ystr >> ystr;
cout << "Hello world!" << endl;
}
return 0;
}
Or, without soci::row
int main()
{
session sql(firebird, "service=D:/New_DB.FDB user=SYSDBA
password=masterkey");
std::string m_name;
double ystr;
soci::statement stmt = (sql.prepare << "select * from materials",
into(m_name), into(ystr), into(ystr));
stmt.execute(false); // false to not fetch any data until loop
while(stmt.fetch())
{
std::cout << "m_name: " << m_name << "; ystr = " << ystr <<
std::endl;
}
return 0;
}
Arnaud
On 12/07/2015 09:08, Sonya Blade wrote:
Hi All,
I'd like to know how one is supposeed to iterate through rows of
resulting database. For example if I have
following code the resulting dataset is returned into r (row)
variable, but I don't know how iterate through it.
Any help will be appreicated,
Regards,
int main()
{
session sql(firebird, "service=D:/New_DB.FDB user=SYSDBA
password=masterkey");
row r;
sql << "select * from materials", into(r);
std::string m_name;
double ystr;
r >> m_name >> ystr >> ystr;
cout << "Hello world!" << endl;
return 0;
}
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