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  • QSqlQuery绑定查询

    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.

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  • 原文地址:https://www.cnblogs.com/wiessharling/p/2874270.html
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