qt sqlite select example

#open3. When programming, be careful to fill in qsqlite, not SQLiteQsqldatabase database = Qsqldatabase::adddatabase ("Qsqlite");4. When using the Qsqldatabase::adddatabase function, if it is a temporary object, then name it, for example (the key is the second parameter):Qsqldatabase LocalDB = qsqldatabase::adddatabase ("Qsqlite", "old_db");If you do not write this second argument, then the new connection will be treated as a default connection, so th

results are exactly the same as those in the previous example (normal data insertion), but they are much better than the former in terms of execution efficiency. 4. Data Query: Data Query is the most basic function provided by each relational database. The following code example shows how to obtain data through the SQLite API.1). Create a test data table.2) Inse

record, so we call it a result set.while (Query.next ()) QString name = Query.value (0). toString (); Returns the index value of the "Name" field "Justin", Value (i) returns the values of the I field, 0 means that name,1 represents ageint id = query.value (1). ToInt (); seek (int n): query points to the nth record of the result set. Specify the current location first (): query points to a record in the result set. Last (): Query points to the final record of the result set. Next (): query point

qsqlrelationaltablemodel->inheritsqsqltablemodel-> Inheritsqsqlquerymodel->inheritsqabstracttablemodel->inheritsqabstractitemmodel-> InheritsV: qsqlrelationaltablemodel--This class provides an editable data model for a single-sheet database table that supports foreign keys, except that they are not different from Qsqltablemodel.Model->setrelation (2,qsqlrelation ("course", "id", "name")); Set the foreign key//student The third property of the table to the foreign key of the ID property of the c

SQLite tutorial (13): C language programming example code (1), sqlite programming example 1. Get the table Schema information: 1) dynamically create a table. 2) obtain the table field information, such as the number of fields and the type of each field, based on the API provided by sqlite3. 3). Delete the table. See th

("Nanchong"); Sql_query.addbindvalue (Groupids); Sql_query.addbindvalue (Groupnames); Sql_query.addbindvalue (groupaddress); if(!Sql_query.execbatch ()) {Qdebug ()Sql_query.lasterror (); } Else{qdebug ()"Insert Record succeeded"; } //querying all Records Sql_query.prepare (Select_all_sql); if(!sql_query.exec ()) {Qdebug ()Sql_query.lasterror (); } Else { while(Sql_query.nex

QT and sqlite3 have been used in recent work. Here we record some of the knowledge points used: specifically, tableview is used in the QT widget to display the content in the SQLite database table. Suppose there are database files test. DB, tables (ID integer, name nvarchar (20), age integer), and there are several pieces of data ...... (Randomly created tables)

. After installing the arm version of Sqlite3, go to the installation directory Sqlite3_arm The Lib directory, the contents are as follows libsqlite3.a libsqlite3.so libsqlite3.so.0.8.6Libsqlite3.la libsqlite3.so.0 Pkgconfig 2. Copy the libsqlite3.a to your own application directory (for example, my Qtcreator application test_sqlite_static)At the same time copy the Sqlite3_arm's include directory under Sqlite3.h to Test_sqlite_static 3. Under the Test

. prepare ("select count (*) from goldVip"); _query.exe c (); _ query. next (); _ a = _ query. value (0 ). toInt (); _ query. prepare ("select count (*) from Vip"); _query.exe c (); _ query. next (); _ B = _ query. value (0 ). toInt (); _ query. prepare ("select count (*) from Coustomer"); _ q Uery.exe c (); _ query. next (); _ c = _ query. value (0 ). toInt ();

::database(dbName); }else//否则打开这个数据库，注意带上数据库名 = QSqlDatabase::addDatabase("QSQLITE",dbName);Three. class invocation of the related databaseBecause of the introduction of multiple databases, the corresponding class calls are introduced into the database connection object.3.1 QsqlquerySQL query class, you can execute various SQL directives. The default method of use is QSqlQueryquery(); query.exec("select * from table1");But this situation, in

SQLite, as long as you have used a database, you should not be afraid of it. It is enough to think of it as a simple database, but it only supports limited data. Next, let me talk about how to use it. My environment is vs2008 + QT. Like most people, I first need to Google the Code. The Code is as follows: # Include Run the command to view the result: Qsqldatabase: qsqlite driver not loadedQsqldatabase: av

Sqlite3 compilation and Installation ------------------------ Arm version ---------------------- 1.download sqlite-autoconf-3070602.tar.gz from the official website 2. decompress the package and enter the current directory. 3. Start the configuration and execute the following command (the cross-compilation environment must be configured ):./Configure -- prefix =/usr/local/sqlite_arm -- Host = arm-Linux 4. Start compilation and run the follow

example, the main function), and the declared qsqldatabase object is in the same scope; If the execution result of qsqlquery can be obtained in the debug debugging status when other functions or scopes of non-qsqldatabase objects are involved, however, the desired results will not be obtained in the non-Debug debugging status (for example, the SELECT statement i

SQL insert statementCsdatabase. executenonquery ("Insert into customer (name, city) values (@ name, @ City)",New{Name ="Microsoft", City ="Redmond"}); // Execute a select SQL statement and map the result to a class Class Queryresult { Public String Name; Public Int Numsales; Public Decimal Totalsales;} queryresult [] Results = Csdatabase. runquery ( @" Select name, count (*), sum (S. To

#include #include#include#includeintMainintargcChar*argv[]) {Qcoreapplication A (argc, argv); Qsqldatabase DB= Qsqldatabase::adddatabase ("Qsqlite"); Db.setdatabasename ("student.db"); if(!Db.open ()) {Qdebug ()"Open Err"; } Else{qdebug ()"database is OK"; } qsqlquery query (db); BOOLisOK = Query.exec ("CREATE TABLE stud (ID int primary key,name varchar )"); Query.exec ("INSERT INTO stud values (111, ' liming ')"); Query.exec ("INSERT INTO stud values (102, ' Li ')"); Query.exec ("INSER

Just likeAndroid SQLiteStatement compilation and execution AnalysisAll SQL statements in SQLite must be compiled to stmt and then executed.The above article introduces SQLiteStatement compilation and execution at the android level. However, SQLiteStatement can only be used to execute SQL statements without return values or with only one row and one column (1X1), such as INSERT ALERT, the returned results such as S