publicUserGetByUsername(stringusername){varuser =fromuinconn.Table<User>()whereu.Username == usernameselectu;returnuser.FirstOrDefault(); } Update and delete rows You update a row using theSQLiteConnectionobject'sUpdatemethod. You provide an object defining the row to be updated with its new ...
Use Python Variable in a query to Delete Row from SQLite table Most of the time, we need to delete a row from an SQLite table where the id passed at runtime. For example, when a user cancels his/her subscription, we need to delete the entry from a table as per the user id. In ...
数据库中TABLE(表)的概念,对应Excel中Sheet;数据库中row(行)、column(列)的概念,对应Excel的行(被标记为1234的那些)和列(被标记为ABCD的那些)的概念。 数据库常用的六个操作,建表、丢表(删除表)、增、删、改、查,其SQL语句如下所示。 建表 CREATETABLE数据表名称(字段1类型1(长度),字段2类型2(长度) …...
char sql = "SELECT * FROM Book;"; sqlite3_stmt* stmt = NULL; /* 数据集 */ /* -1代表系统会自动计算SQL语句的长度 */ sqlite3_prepare(br_sqlite3->db, sql, -1, &stmt, NULL) /* 每调一次sqlite3_step()函数,stmt就会指向下一条记录 */ while(sqlite3_step(stmt) == SQLITE_ROW) {...
);--文件删除历史表createtablefile_remove_history ( idintegerprimarykey, user_accountnvarchar(32)notnull,user_namenvarchar(32)notnull, file_pathnvarchar(256)notnull, upload_start_timetimestamp, upload_end_timetimestamp, upload_ipnvarchar(20), ...
cmd.CommandText="PRAGMA table_info('t1')";//方法一:用DataAdapter和DataTable类,调用方法为using System.DataSQLiteDataAdapter adapter =newSQLiteDataAdapter(cmd); DataTable table=newDataTable(); adapter.Fill(table);foreach(DataRow rintable.Rows) ...
storage.remove_all<User>(where(c(&User::id) < 100));Raw selectIf you need to extract only a single column (SELECT %column_name% FROM %table_name% WHERE %conditions%) you can use a non-CRUD select function:// SELECT id FROM users auto allIds = storage.select(&User::id); cout ...
void deleteRow(); void updateActions(); public slots: void exec(); void showTable(const QString &table); void showMetaData(const QString &table); void addConnection(); void currentChanged() { updateActions(); } void about(); void on_insertRowAction_triggered() ...
create table events ( id integer primary key, name text not null, startTime date not null, locationId integer references locations ); If you want to get one row with the basic API, you can use: const event = await db.events.get({ id: 100 }); If you want to get many rows, you...
(databaseName.isEmpty())returntrue;if(!QFile::exists(dbFilePath)){returnfalse;//数据库不存在}db=QSqlDatabase::database(databaseName);if(!db.isValid()){returntrue;}db.close();db=QSqlDatabase::database();QSqlDatabase::removeDatabase(databaseName);databaseName="";dbFilePath="";...