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50 #include <QSqlDatabase>
51 #include <QSqlQuery>
52 #include <QSqlDriver>
53 #include <QDebug>
54
openDatabase()55 void openDatabase()
56 {
57 //! [0]
58 // WRONG
59 QSqlDatabase db = QSqlDatabase::database("sales");
60 QSqlQuery query("SELECT NAME, DOB FROM EMPLOYEES", db);
61 QSqlDatabase::removeDatabase("sales"); // will output a warning
62 // "db" is now a dangling invalid database connection,
63 // "query" contains an invalid result set
64 //! [0]
65 }
66
removeDatabase()67 void removeDatabase()
68 {
69 //! [1]
70 {
71 QSqlDatabase db = QSqlDatabase::database("sales");
72 QSqlQuery query("SELECT NAME, DOB FROM EMPLOYEES", db);
73 }
74 // Both "db" and "query" are destroyed because they are out of scope
75 QSqlDatabase::removeDatabase("sales"); // correct
76 //! [1]
77 }
78
setmyDatabase()79 void setmyDatabase()
80 {
81 //! [3]
82 // ...
83 QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
84 db.setDatabaseName("DRIVER={Microsoft Access Driver (*.mdb, *.accdb)};FIL={MS Access};DBQ=myaccessfile.mdb");
85 if (db.open()) {
86 // success!
87 }
88 // ...
89 //! [3]
90 }
91
92 // ...
93 // MySQL connection
dbConnect()94 void dbConnect()
95 {
96 QSqlDatabase db;
97 //! [4]
98 db.setConnectOptions("SSL_KEY=client-key.pem;SSL_CERT=client-cert.pem;SSL_CA=ca-cert.pem;CLIENT_IGNORE_SPACE=1"); // use an SSL connection to the server
99 if (!db.open()) {
100 db.setConnectOptions(); // clears the connect option string
101 // ...
102 }
103 // ...
104 // PostgreSQL connection
105 db.setConnectOptions("requiressl=1"); // enable PostgreSQL SSL connections
106 if (!db.open()) {
107 db.setConnectOptions(); // clear options
108 // ...
109 }
110 // ...
111 // ODBC connection
112 db.setConnectOptions("SQL_ATTR_ACCESS_MODE=SQL_MODE_READ_ONLY;SQL_ATTR_TRACE=SQL_OPT_TRACE_ON"); // set ODBC options
113 if (!db.open()) {
114 db.setConnectOptions(); // don't try to set this option
115 // ...
116 }
117 }
118 //! [4]
119
dbQdebug()120 void dbQdebug()
121 {
122 //! [8]
123 QSqlDatabase db;
124 qDebug() << db.isValid(); // Returns false
125
126 db = QSqlDatabase::database("sales");
127 qDebug() << db.isValid(); // Returns \c true if "sales" connection exists
128
129 QSqlDatabase::removeDatabase("sales");
130 qDebug() << db.isValid(); // Returns false
131 //! [8]
132 }
133