Approaches to Binding Values
Below we present the same example using each of the four different binding approaches, as well as one example of binding values to a stored procedure.
Named binding using named placeholders:
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (:id, :forename, :surname)");
query.bindValue(":id", 1001);
query.bindValue(":forename", "Bart");
query.bindValue(":surname", "Simpson");
query.exec();
Positional binding using named placeholders:
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (:id, :forename, :surname)");
query.bindValue(0, 1001);
query.bindValue(1, "Bart");
query.bindValue(2, "Simpson");
query.exec();
Binding values using positional placeholders (version 1):
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (?, ?, ?)");
query.bindValue(0, 1001);
query.bindValue(1, "Bart");
query.bindValue(2, "Simpson");
query.exec();
Binding values using positional placeholders (version 2):
QSqlQuery query;
query.prepare("INSERT INTO person (id, forename, surname) "
"VALUES (?, ?, ?)");
query.addBindValue(1001);
query.addBindValue("Bart");
query.addBindValue("Simpson");
query.exec();
Binding values to a stored procedure:
This code calls a stored procedure called AsciiToInt(), passing it a character through its in parameter, and taking its result in the out parameter.
QSqlQuery query;
query.prepare("CALL AsciiToInt(?, ?)");
query.bindValue(0, "A");
query.bindValue(1, 0, QSql::Out);
query.exec();
int i = query.boundValue(1).toInt(); // i is 65
Note that unbound parameters will retain their values.
More information to see QT Help.
本文來(lái)自ChinaUnix博客，如果查看原文請(qǐng)點(diǎn)：http://blog.chinaunix.net/u2/86708/showart_1945836.html |