QSqlQuery绑定查询

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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.

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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.