代码块含义大体解析:
1.
QSqlDatabase mCurDatabase;
QString driverName = mCurDatabase.driverName();
返回连接的驱动名。
如QSQLITE
2.sqlite数据库中查询是否存在表tableName
select * from sqlite_master where type = 'table' and name=tableName
3.
QSqlQuery query(db);query.exec(sql);res = query.first();
进行sql语句的查询,如果查询成功,返回true,未查询到结果,返回false
4.
QSqlDatabase mCurDatabase;if(!mCurDatabase.isValid())return ;
QSqlDatabase db;
qDebug() << db.isValid(); // Returns falsedb = QSqlDatabase::database("sales");
qDebug() << db.isValid(); // Returns \c true if "sales" connection existsQSqlDatabase::removeDatabase("sales");
qDebug() << db.isValid(); // Returns false
5.
QByteArray allMsg;
QList<QByteArray> sqls = allMsg.split(';');
以';'划分出多个QByteArray对象
6.
QByteArray ba(" lots\t of\nwhitespace\r\n ");
ba = ba.simplified();
// ba == "lots of whitespace";
去掉'\t', '\n', '\v', '\f', '\r', and ' '.
7.QSqlQuery查询后,得到QSqlRecord,可以得到record中的字段名称和相关值。
QSqlRecord records = query.record();for(int index = 0; index < records.count(); index++){QString fieldName = records.fieldName(index);QVariant value = records.value(index);}
8.fetch:拿来
9.uuid
通用唯一识别码(Universally Unique Identifier)