This
article introduced a simple C++ database library,
SOCI. According to the author, users only need to know two classes,
Session and
Statement, to complete most of interactions between client programs and database servers.
The following sample, excerpted from the article, demonstrated the simplicity of the library.
- Session and Statement classes hide OCI calls from the users.
- Free function use() binds variables to placeholders in the SQL statements.
- Free function into() populates the variables with the values returned by select statements.
- Shift operator in the Session enables storing a query and starts creating a temporary object that handles the rest of the expression.
- Comma operator stores parameter information returned by use and into functions into the temporary object for later use.
- The temporary object executes the sql statements in its destructor.
#include "soci.h"
#include <iostream>
using namespace std;
using namespace SOCI;
int main()
{
try
{
Session sql("DBNAME", "user", "password");
// example 1. - basic query with one variable used
int count;
sql << "select count(*) from some_table", into(count);
// example 2. - basic query with parameter
int id = 7;
string name;
sql << "select name from person where id = " << id, into(name);
// example 3. - the same, but with input variable
sql << "select name from person where id = :id", into(name), use(id);
// example 4. - statement with no output
id = 8;
name = "John";
sql << "insert into person(id, name) values(:id, :name)", use(id), use(name);
// example 5. - statement used multiple (three) times
Statement st1 = (sql.prepare <<
"insert into country(id, name) values(:id, :name)",
use(id), use(name));
id = 1; name = "France"; st1.execute(1);
id = 2; name = "Germany"; st1.execute(1);
id = 3; name = "Poland"; st1.execute(1);
// example 6. - statement used for fetching many rows
Statement st2 = (sql.prepare << "select name from country", into(name));
st2.execute();
while (st2.fetch())
{
cout << name << '\n';
}
}
catch (exception const &e)
{
cerr << "Error: " << e.what() << '\n';
}
}
